FLAC程序使用手册

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FLAC_3D快速入门(手册翻译版——一米)

FLAC_3D快速入门(手册翻译版——一米)FLAC3D3.0版本3.0中文手册一米固定y范围y -0.1 0.1固定y范围y 7.9 8.1固定z范围z -0.1 0.1应用szz -1e6范围z 7.9 8.1 hist unb hist总成xvel 3 4 4 hist总成zdisp 0 0 8 step 1500；求解(可使用步进命令或求解命令)模型开始时，最大不平衡力为1MN。

经过1500步计算，最大不平衡力下降到大约270牛顿。

通过绘制第一个历史变量图，我们可以看到最大不平衡力接近“0”。

输入以下命令，在FLAC3D中显示图2.15中的图像:图表hist 1输入:图表hist 2图表hist 3. 43。

FLAC3D3.0版本3.0中文手册一米图2.15最大不平衡力记录可以分别看到记录节点的速度记录图(见图 2.16)和位移记录图(见图2.16)。

. 44。

FLAC3D3.0版本3.0中文手册一米2.17).从图2.16中可以看出，速度值已经接近“0”；我们还可以在图2.17中看到位移值已经接近固定值。

上述条件都说明了一件事:模型已经达到初始平衡状态。

图2.16节点(3，4，4)x向速度记录图图2.17节点(0，0，8)z向位移记录图. 45。

FLAC3D3.0版本3.0中文手册一米如果用户希望FLAC3D在计算结束时自动控制(当最大不平衡力小于某个极限值时)，他可以使用求解而不是步进命令。

在上面的例子中，步骤1500可以由sovle代替。

这一次，计算将在1650停止。

如果也记录了上述变量的历史记录，则绘制的图表应与前三个图表大体相同。

如果我们使用求解命令，默认情况下，系统通过最大不平衡力的比值来控制计算过程。

当最大不平衡力与初始施加的节点力的平均值之比小于1×10-5时，计算将停止。

在输入求解命令之前，我们也可以通过输入以下命令来手动设置该比率:在这里设置机械比率= f，f是用户给出的比率限制。

FLAC程序使用手册

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为 ri 和 rj. GEn Circle xc,yc rad Arc xc,yc xb,yb theta Line x1,y1 x2,y2 该命令产生园、弧或直线。 ARC 弧的圆心为 (xc,yc), 起始点为 (xb,yb), 逆时针的角为 theta 度 CIRCLE 园的中心为 (xc,yc), 半径为 rad LINE 直线的两端为 (x1,y1) 和 (x2,y2). 用 ARC 等关键词所形成的边界系被标记 (参见命令 MARK 和 UNMARK)过, 标记结点所围住的区域在以后用命令 INITAL, MODEL 和 PROPERTY 时可以用关键词 REGION 来说明。 ADJust 用此命令来微调网格, 使之离散平滑。该命令可以连续使用以增进平滑效果的。 Grid icol jrow 此命令用以产生数目为 icol 列和 jrow 行的网格。对于 640k 内存的 FLAC 版本, 如用摩尔-库仑的本构模型约可分两千个单元。 Help 帮助命令, 可在屏幕上显示命令表。 His <Nstep=n> <关键词 . . . I=i1 J=j1> 每隔 NSTEP 时步, 记录一下关键词所示项目在 i1 和 ji 结点或单元的数值。 NSTEP 的缺省值为 10. 用户应记住所要求 His (历史)的顺序, 因以后在打印或绘图时要用。历史值在 FLAC 停止运行时删除, 因此如果要保留的话, 要用到命令 HIS WRITE N (见下面)。可以用的关键词有: Ang 单元 i,j 内的最小主应力和 X-轴所形成的夹角 PP 单元 i,j 内的孔隙压力 SIG1 单元 i,j 的最大主应力 SIG2 单元 i,j 的最小主应力 SXX 单元 i,j 的 xx-应力 SYY 单元 i,j 的 yy-应力 SXY 单元 i,j 的 xy-应力 X 结点 i,j 的 x-坐标 Y 结点 i,j 的 y-坐标 XDis 结点 i,j 的 x-位移 YDis 结点 i,j 的 y-位移 Unbal 最大不平衡力 XVel 结点 i,j 的 x-速度 YVel 结点 i,j 的 y-速度 XXA 单元 i,j 三角形 a 的 xx-应力 XYA 单元 i,j 三角形 a 的 xy-应力 YYA 单元 i,j 三角形 a 的 yy-应力 XXB 单元 i,j 三角形 b 的 xx-应力 XYB 单元 i,j 三角形 b 的 xy-应力 YYB 单元 i,j 三角形 b 的 yy-应力 XXC 单元 i,j 三角形 c 的 xx-应力 XYC 单元 i,j 三角形 c 的 xy-应力 YYC 单元 i,j 三角形 c 的 yy-应力 XXD 单元 i,j 三角形 d 的 xx-应力 XYD 单元 i,j 三角形 d 的 xy-应力 YYD 单元 i,j 三角形 d 的 yy-应力 His 关键词关键词可以是: Dump nhis 将第 nhis 的历史写屏;

Flac3D使用手册

3INTERFACES3.1General CommentsThere are several instances in geomechanics in which it is desirable to represent planes on which sliding or separation can occur—for example:1.joint,fault or bedding planes in a geologic medium;2.an interface between a foundation and the soil;3.a contact plane between a bin or chute and the material that it contains;4.a contact between two colliding objects;and5.a planar“barrier”in space,which represents aﬁxed,non-deformable boundaryat an arbitrary position and orientation.FLAC3D provides interfaces that are characterized by Coulomb sliding and/or tensile and shear bonding.Interfaces have the properties of friction,cohesion,dilation,normal and shear stiffnesses, tensile and shear bond strength.Although there is no restriction on the number of interfaces or the complexity of their intersections,it is generally not reasonable to model more than a few simple interfaces with FLAC3D because it is awkward to specify complicated interface geometry.The program3DEC(Itasca1998)is speciﬁcally designed to model many interacting bodies in three dimensions;it should be used instead of FLAC3D for the more complicated interface problems. Interfaces may also be used to join regions that have different zone sizes.In general,the ATTACH command should be used to join grids together.However,in some circumstances it may be more convenient to use an interface for this purpose.In this case,the interface is prevented from sliding or opening because it does not correspond to any physical entity.3.2FormulationFLAC 3D represents interfaces as collections of triangular elements (interface elements),each of which is deﬁned by three nodes (interface nodes).Interface elements can be created at any location in space.Generally,interface elements are attached to a zone surface face;two triangular interface elements are deﬁned for every quadrilateral zone face.Interface nodes are then created automatically at every interface element vertex.When another grid surface comes into contact with an interface element,the contact is detected at the interface node,and is characterized by normal and shear stiffnesses,and sliding properties.Each interface element distributes its area to its nodes in a weighted fashion.Each interface node has an associated representative area.The entire interface is thus divided into active interface nodes representing the total area of the interface.Figure 3.1illustrates the relation between interface elements and interface nodes and the representative area associated with an individual node.elementinterfaceFigure 3.1Distribution of representative areas to interface nodesIt is important to note that interfaces are one-sided in FLAC 3D .(This differs from the formulation of two-sided interfaces in two-dimensional FLAC (Itasca 2000).)It may be helpful to think of FLAC 3D interfaces as “shrink-wrap”that is stretched over the desired surface,causing the surface to become sensitive to interpenetration with any other face with which it may come into contact.The fundamental contact relation is deﬁned between the interface node and a zone surface face,also known as the target face .The normal direction of the interface force is determined by the orientation of the target face.During each timestep,the absolute normal penetration and the relative shear velocity are calculated for each interface node and its contacting target face.Both of these values are then used by the interface constitutive model to calculate a normal force and a shear-force vector.The constitutive model is deﬁned by a linear Coulomb shear-strength criterion that limits the shear force acting at an interface node,normal and shear stiffnesses,tensile and shear bond strengths,and a dilation angle that causes an increase in effective normal force on the target face after the shear-strength limit is reached.By default,pore pressure is used in the interface effective stress calculation.This option can be activated/deactivated using the command INTERFACE i effective=on/off.Figure3.2 illustrates the components of the constitutive model acting at interface node(P).Figure3.2Components of the bonded interface constitutive modelThe normal and shear forces that describe the elastic interface response are determined at calculation time(t+ t)using the following relations.F(t+ t)n=k n u n A+σn A(3.1)F(t+ t) si =F(t)si+k s u(t+(1/2) t)siA+σsi Awhere F(t+ t)n is the normal force at time(t+ t)[force];F(t+ t)si is the shear force vector at time(t+ t)[force];u n is the absolute normal penetration of the interface nodeinto the target face[displacement];u si is the incremental relative shear displacement vector[displacement];σn is the additional normal stress added due to interface stressinitialization[force/displacement];k n is the normal stiffness[stress/displacement];k s is the shear stiffness[stress/displacement];σsi is the additional shear stress vector due to interface stressinitialization;andA is the representative area associated with the interface node[length2].The inelastic interface logic works in the following way:(1)Bonded interface—The interface remains elastic if stresses remain below the bondstrengths:there is a shear bond strength as well as a tensile bond strength.The nor-mal bond strength is set using the tension interface property keyword.The commandINTERFACE n prop sbratio=sbr sets the shear bond strength to sbr times the normal bondstrength.The default value of sbratio(if not given)is100.0.The bond breaks if either theshear stress exceeds the shear strength,or the tensile effective normal stress exceeds thenormal strength.Note that giving sbratio alone does not cause a bond to be established;the tensile bond strength must also be set.(2)Slip while bonded—An intact bond,by default,prevents all yield behavior(slip andseparation).There is an optional property switch(bslip)that causes just separationto be prevented if the bond is intact(but allows shear yield,under the control of thefriction and cohesion parameters,using abs(F n)as the normal force).The command toallow/disallow slip for a bonded interface segment isINTER n PROP bslip=onbslip=offThe default state of bslip(if not given)is off.(3)Coulomb sliding—A bond is either intact or broken.If it is broken,then the behaviorof the interface segment is determined by the friction and cohesion(and of course thestiffnesses).This is the default behavior,if bond strengths are not set(zero).A brokenbond segment cannot take effective tension(which may occur under compressive normalforce,if the pore pressure is greater).The shear force is zero(for a non-bonded segment)if the effective normal force is tensile or zero.The Coulomb shear-strength criterion limits the shear force by the following relation.F smax=cA+tanφ(F n−pA)(3.2)where c is the cohesion[stress]along the interface;φis the friction angle[degrees]of the interface surface;andp is pore pressure(interpolated from the target face),provided the keywordeffective=off has not been issued for the interface.If the criterion is satisﬁed(i.e.,if|F s|≥F smax),then sliding is assumed to occur,and |F s|=F smax,with the direction of shear force preserved.During sliding,shear displacement may cause an increase in the effective normal stress on the joint,according to the relation:σn:=σn+|F s|o−F smaxAk s tanψk n(3.3)whereψis the dilation angle[degrees]of the interface surface;and|F s|o is the magnitude of shear force before the above correction is made.On printout(PRINT interface n prop tens),the value of tension denotes if a bond is intact or broken (or not set)—non-zero or zero,respectively.The normal and shear forces calculated at the interface nodes are distributed in equal and opposite directions to both the target face and the face to which the interface node is connected(the host face). Weighting functions are used to distribute the forces to the gridpoints on each face.The interface stiffnesses are added to the accumulated stiffnesses at gridpoints on both sides of the interface,in order to maintain numerical stability.Interface contacts are detected only at interface nodes,and contact forces are transferred only at interface nodes.The stress state associated with a node is assumed to be uniformly distributed over the entire representative area of the node.Interface properties are associated with each node; properties may vary from node to node.By default,the effect of pore pressure is included in the interface calculation by using effective stress as the basis for the slip condition.(The interface pore pressure is interpolated from the target face.)This applies either in CONFIGﬂuid mode,or if pore pressures are assigned with the WATER table or INITIAL pp command without specifying CONFIGﬂuid.The user can switch options for interface i by using the command INTERFACE i effective=on/off.By default,in the FLAC3D logic,ﬂuidﬂow—saturated or unsaturated—is carried across an interface,provided the interface keyword maxedge is not used for that particular interface.The permeable interface option can be deactivated/reactivated for interface i by using the command INTERFACE i perm=on/off.Note that if the keyword maxedge is used,and perm is on for a particular interface,a warning is issued to inform the user that this interface will be considered as impermeable toﬂuidﬂow.(Note that, forﬂuidﬂow calculation only,a mechanical model must be present.Also,the command CYCLE 0with SET mech on should be used to initialize the weighting factors used to transferﬂuidﬂow information across the interface.)No pressure drop normal to the joint and no inﬂuence of normal displacement on pore pressure are calculated.Also,ﬂow ofﬂuid along the interface is not modeled.3.3Creation of Interface GeometryInterfaces are created with the INTERFACE command.For cases in which an interface is required between two separate grids in the model,the command INTERFACE i face range...should be used to attach an interface to one of the grid surfaces.This command generates interface elements for interface i along all surface zone faces with a center point that fall within a speciﬁed range.Any surfaces on which an interface is to be created must be generated initially with some separation between the adjacent surfaces;it must be possible to specify an existing surface in order to create the interface elements.(Also,a gap must be speciﬁed between the two grids because the grid generator will automatically merge surface gridpoints if they are created at the same location in space.)By default,two interface elements are created for each zone face.The number of interface elements can be increased by using the command INTERFACE i maxedge v.*This causes all interface elements with edge lengths larger than v to subdivide into smaller elements until their lengths are smaller than v.This command can be used to increase the resolution and decrease arching of forces in portions of a model that have large contrasts in zone size across an interface.The following rules should be followed when using interface elements in FLAC3D.1.If a smaller surface area contacts a larger surface area(e.g.,a small block restingon a large block),the interface should be attached to the smaller region.2.If there is a difference in zone density between two adjacent grids,the interfaceshould be attached to the grid with the greater zone density(i.e.,the greaternumber of zones within the same area).3.The size of interface elements should always be equal to or smaller than thetarget faces with which they will come into contact.If this is not the case,theinterface elements should be subdivided into smaller elements.4.Interface elements should be limited to grid surfaces that will actually comeinto contact with another grid.A simple example illustrating the procedure for interface creation is provided in Example3.1.The example is a block specimen containing a single joint dipping at an angle of45◦.Example3.1Creating a model with a dipping joint;Create Basegen zone brick size333&p0(0,0,0)p1(3,0,0)p2(0,3,0)p3(0,0,1.5)&p4(3,3,0)p5(0,3,1.5)p6(3,0,4.5)p7(3,3,4.5)group Base*Note that if CONFIGﬂuid is invoked,and perm is on for a particular interface,specifying maxedge for that interface will automatically make it impermeable.Do not specify maxedge ifﬂow across the interface is desired.;Create Top-1unit high for initial spacinggen zone brick size333&p0(0,0,2.5)p1(3,0,5.5)p2(0,3,2.5)p3(0,0,7)&p4(3,3,5.5)p5(0,3,7)p6(3,0,7)p7(3,3,7)group Top range group Base not;;Create interface elements on the top surface of the baseinterface1face range plane norm(-1,0,1)origin(1.5,1.5,3)dist0.1;plot create view_intplot add surfaceplot add interface redplot showpause;;Lower top to complete geometryini z add-1.0range group Topsave int.savFigure3.3shows the grid before the interface is created.Two sub-grid groups are deﬁned:a Base grid,and a Top grid.Figure3.4shows the model with the interface elements attached to the Base grid.Figure3.5shows theﬁnal geometry with the sub-grids moved together.A uniaxial compression test with this model is described later in Section3.4.3.Figure3.3Initial geometry before creation of the interfaceFigure3.4Interface elements addedFigure3.5Final geometry3.4Choice of Material PropertiesAssignment of material properties(particularly stiffnesses)to an interface depends on the way in which the interface is used.Three possibilities are common.The interface may be:1.an artiﬁcial device to connect two sub-grids together;2.a real interface that is stiff compared to the surrounding material,but which canslip and perhaps open in response to the anticipated loading.(This case alsoencompasses the situation in which stiffnesses are unknown or unimportant,but where slip and/or separation will occur—e.g.,ﬂow of frictional materialin a bin);or3.a real interface that is soft enough to inﬂuence the behavior of the system(e.g.,a joint with soft clayﬁlling or a dyke containing heavily fractured material).These cases are examined in detail.3.4.1Interface Used to Join Two Sub-gridsIf possible,sub-grids should be joined with the ATTACH command.It is more computationally-efﬁcient to use ATTACH than INTERFACE to join sub-grids.See Section3.2.1.2in the User’s Guide, for a description of,and restrictions on,the ATTACH command.Under some circumstances it may be necessary to use an interface to join two sub-grids.This type of interface is assigned high strength properties with the INTERFACE command,thus preventing any slip or separation.(This is the equivalent of a“glued”interface in FLAC.)Shear and normal stiffnesses must also be provided;values of friction and cohesion are not needed.It is tempting (particularly for people familiar withﬁnite element methods)to give a very high value for these stiffnesses to prevent movement on the interface.However,FLAC3D does“mass scaling”(see Section1.1.2.6)based on stiffnesses—the response(and solution convergence)will be very slow if very high stiffnesses are speciﬁed.It is recommended that the lowest stiffness consistent with small interface deformation be used.A good rule-of-thumb is that k n and k s be set to ten times the equivalent stiffness of the stiffest neighboring zone.The apparent stiffness(expressed in stress-per-distance units)of a zone in the normal direction ismax K+43Gz min(3.4)where K&G are the bulk and shear moduli,respectively;andz min is the smallest width of an adjoining zone in the normal direction—seeFigure3.6.The max[]notation indicates that the maximum value over all zones adjacent to the interface is to be used(e.g.,there may be several materials adjoining the interface).InterfaceFigure3.6Zone dimension used in stiffness calculationTo illustrate the approach,consider Figure3.7,in which two sub-grids of unequal zoning are joined by the commands in Example3.2and are loaded by a pressure on the left-hand part of the upper surface:Example3.2Joining two sub-gridsgen zone brick size444p00,0,0p14,0,0p20,4,0p30,0,2gen zone brick size884p00,0,3p14,0,3p20,4,3p30,0,5inter1face range z 2.9,3.1inter1prop kn300e9ks300e9tens1e10SBRATIO=1ini z add-1.0range z 2.9,5.1model elasprop bulk8e9shear5e9fix z range z-.1.1fix x range x-.1.1fix x range x 3.9 4.1fix y range y-.1.1fix y range y 3.9 4.1apply szz-1e6range z 3.9 4.1x0,2y0,2hist unbalsolvesave join.savThe value of(K+4G/3)is15GPa,and the minimum zone size adjacent to the interface is 0.5m.Hence,we choose both shear stiffness and normal stiffness to be150×109/0.5—i.e., k n=k s=3×1011Pa/m.The resulting contours of z-displacement are shown in Figure3.8.Compare this result to that for a single grid,shown in Figure3.7in the User’s Guide.This plot is at the same scale and contour intervals as Figure3.8.The two plots are almost identical,which indicates that the interface does not affect the behavior to any great extent.The prescription given in Eq.(3.4)is reasonable if the materials on the two sides of the interface are similar,and variations of stiffness occur only in the lateral directions.However,if the material on one side of the interface is much stiffer than that on the other,then Eq.(3.4)should be applied to the softer side.In this case,the deformability of the whole system is dominated by the soft side;making the interface stiffness ten times the soft-side stiffness will ensure that the interface has minimal inﬂuence on system compliance.Figure3.7Two unequal sub-grids joined by an interfaceFigure3.8Vertical displacement contours—two joined grids3.4.2Real Interface—Slip and Separation OnlyIn this case,we simply need to provide a means for one sub-grid to slide and/or open relative to another sub-grid.The friction(and perhaps cohesion,dilation,and tensile strength)is important, but the elastic stiffness is not.The approach of Section3.4.1is used here to determine k n and k s. However,the other material properties are given real values(see Section3.4.3for advice on choice of properties).As an example,we can allow slip in a bin-ﬂow problem,as shown in Figure3.9,corresponding to the dataﬁle in Example3.3.The bond strengths are not set(i.e.,they default to zero);the interface stiffnesses are set to approximately ten times the equivalent stiffness of the neighboring zones.Figure3.9Flow of frictional material in a“bin”Example3.3Slip in a bin-ﬂow problem;Create Material Zonesgen zone brick size555&p0(0,0,0)p1(3,0,0)p2(0,3,0)p3(0,0,5)&p4(3,3,0)p5(0,5,5)p6(5,0,5)p7(5,5,5) gen zone brick size555p0(0,0,5)edge 5.0group Material;Create Bin Zonesgen zone brick size155&p0(4,1,0)p1add(3,0,0)p2add(0,3,0)&p3add(2,0,5)p4add(3,6,0)p5add(2,5,5)&p6add(3,0,5)p7add(3,6,5)gen zone brick size155&p0(6,1,5)p1add(1,0,0)p2add(0,5,0)&p3add(0,0,5)p4add(1,6,0)p5add(0,5,5)&p6add(1,0,5)p7add(1,6,5)gen zone brick size515&p0(1,4,0)p1add(3,0,0)p2add(0,3,0)&p3add(0,2,5)p4add(6,3,0)p5add(0,3,5)&p6add(5,2,5)p7add(6,3,5)gen zone brick size515&p0(1,6,5)p1add(5,0,0)p2add(0,1,0)&p3add(0,0,5)p4add(6,1,0)p5add(0,1,5)&p6add(5,0,5)p7add(6,1,5)group Bin range group Material not;Create named range synonymsrange name=Bin group Binrange name=Material group Material;Assign models to groupsmodel mohr range Materialmodel elas range Bin;Create interface elementsint1face ran plane ori(4,0,0)nor(-5,0,2)dist0.01z(0,5)y(1,6) int2face ran plane ori(0,4,0)nor(0,-5,2)dist0.01z(0,5)x(1,6) int1face ran x 5.9 6.1y16z510int2face ran x16y 5.9 6.1z510int1maxedge0.55int2maxedge0.55;Move bin toward materialini x add-1.0range Binini y add-1.0range Bin;Assign propertiesprop shear1e8bulk2e8fric30range Materialprop shear1e8bulk2e8range Binini den2000int1prop ks2e9kn2e9fric15int2prop ks2e9kn2e9fric15;Assign Boundary Conditionsfix x range x-0.10.1any x 5.9 6.1anyfix y range y-0.10.1any y 5.9 6.1anyfix z range z-0.10.1Bin;Monitor historieshist unbalhist gp zdisp(6,6,10)hist gp zdisp(0,0,10)hist gp zdisp(0,0,0);Settingsset largeset grav0,0,-10;Cyclingstep4000save bin.sav3.4.3All Properties Have Physical SigniﬁcanceIn this case,properties should be derived from tests on real joints*(suitably scaled to account for size effect),or from published data on materials similar to the material being modeled.However, the comments of Section3.4.1also apply here with respect to the maximum stiffnesses that are reasonable to use.If the physical normal and shear stiffnesses are less than ten times the equivalent stiffness of adjacent zones,then there is no problem in using physical values.If the ratio is much more than ten,the solution time will be signiﬁcantly longer than for the case in which the ratio is limited to ten,without much change in the behavior of the system.Serious consideration should be given to reducing supplied values of normal and shear stiffnesses to improve solution efﬁciency. There may also be problems with interpenetration if the normal stiffness,k n,is very low.A rough estimate should be made of the joint normal displacement that would result from the application of typical stresses in the system(u=σ/k n).This displacement should be small compared to a typical zone size.If it is greater than,say,10%of an adjacent zone size,then there is either an error in one of the numbers,or the stiffness should be increased if calculations are to be done in large-strain mode.Joint properties are conventionally derived from laboratory testing(e.g.,triaxial and direct shear tests).These tests can supply physical properties for joint friction angle,cohesion,dilation angle, and tensile strength,as well as joint normal and shear stiffnesses.The joint cohesion and friction angle correspond to the parameters in the Coulomb strength criterion†described in Section3.2. Values for normal and shear stiffnesses for rock joints typically can range from roughly10to100 MPa/m for joints with soft clay in-ﬁlling,to over100GPa/m for tight joints in granite and basalt. Published data on stiffness properties for rock joints are limited;summaries of data can be found in Kulhawy(1975),Rosso(1976),and Bandis et al.(1983).Approximate stiffness values can be back-calculated from information on the deformability and joint structure in the jointed rock mass and the deformability of the intact rock.If the jointed rock mass is assumed to have the same deformational response as an equivalent elastic continuum,then relations can be derived between jointed rock properties and equivalent continuum properties. For uniaxial loading of rock containing a single set of uniformly spaced joints oriented normal to the direction of loading,the following relation applies.1=1r +1n(3.5)*“Joint”is used here as a generic term.†The Coulomb yield surface provides a reasonable approximation for joint strength for most engi-neering calculations.More complex joint models are available which include,for example,effects of continuous yielding and displacement weakening.For analysis with other joint models,the user is referred to UDEC(Itasca1996).ork n=E E rs(E r−E)(3.6)where E=rock mass Young’s modulus;E r=intact rock Young’s modulus;k n=joint normal stiffness;ands=joint spacing.A similar expression can be derived for joint shear stiffness:k s=G G rs(G r−G)(3.7)where G=rock mass shear modulus;G r=intact rock shear modulus;andk s=joint shear stiffness.The equivalent continuum assumption,when extended to three orthogonal joint sets,produces the following relations:E i=1r+1i ni−1(i=1,2,3)(3.8)G ij=1G r+1s i k si+1s j k sj−1(i,j=1,2,3)(3.9)Several expressions have been derived for two-and three-dimensional characterizations and multiple joint sets.References for these derivations can be found in Singh(1973),Gerrard(1982(a)and (b)),and Fossum(1985).Published strength properties for joints are more readily available than stiffness properties.Sum-maries can be found,for example,in Jaeger and Cook(1979),Kulhawy(1975),and Barton(1976). Friction angles can vary from less than10◦for smooth joints in weak rock,such as tuff,to over 50◦for rough joints in hard rock,such as granite.Joint cohesion can range from zero to values approaching the compressive strength of the surrounding rock.It is important to recognize that joint properties measured in the laboratory typically are not rep-resentative of those for real joints in theﬁeld.Scale dependence of joint properties is a major question in rock mechanics.Often,the only way to guide the choice of appropriate parameters is by comparison to similar joint properties derived fromﬁeld tests.However,ﬁeld test observations are extremely limited.Some results are reported by Kulhawy(1975).The following example illustrates an application of the interface logic to simulate the physical response of a rock joint subjected to normal and shear loading.The model represents a direct shear test,which consists of a single horizontal joint that isﬁrst subjected to a normal conﬁning stress, and then to a unidirectional shear displacement.Figure3.10shows the model.Figure3.10Direct shear test modelFirst,a normal stress of10MPa is applied that is representative of the conﬁning stress acting on the joint.A horizontal velocity is then applied to the top sub-grid to produce a shear displacement along the interface.For demonstration purposes,we only apply a small shear displacement of less than2mm to this model.The average normal and shear stresses,and normal and shear displacements along the joint,are measured with a FISH function.With this information we can determine the shear strength and dilation that are produced.The dataﬁle for this test is contained in Example3.4.Example3.4Direct shear testtitleDirect shear testgen zone brick size12110p0406p11606p2416p34011 gen zone brick size20110p12000p2010p3005range name bot z05range name top z611interface1face range z5int1prop ks4e4kn4e4fric30dil6;tension1e10bslip=onini z add-1.0range top;plo surf lorange interface white axes blackmodel eprop bulk45e3sh30e3fix x y z range z0fix x range x0fix x range x20apply nstress-10range z10step0plot contour szz interface white axes blacksolvesave dsta.savini xvel5e-7range topfix xvel range topdef ini_jdispvalnd=0.0count=0.0p_in=i_node_head(i_head)loop while p_in#nullif in_ztarget(p_in)#null thenvalnd=valnd+in_pen(p_in)count=count+ 1.0end_ifp_in=in_next(p_in)end_loopnjdisp0=valnd/countendini_jdispdef sstavvalns=0.0valss=0.0valsd=0.0valnd=0.0count=0.0p_in=i_node_head(i_head)loop while p_in#nullif in_ztarget(p_in)#null thenvalns=valns+in_nstr(p_in)*in_area(p_in)valss=valss+in_sstr(p_in,1)*in_area(p_in)valsd=valsd+in_sdisp(p_in,1)valnd=valnd+in_pen(p_in)count=count+ 1.0end_ifp_in=in_next(p_in)end_loopsstav=valss/(12.0*1.0)nstav=valns/(12.0*1.0)sjdisp=valsd/countnjdisp=valnd/count-njdisp0endhist ns1hist sstav nstav sjdisp njdispini xdis0ydis0zdis0step2500save dst.savplot his-1vs-3pauseplot his-4vs-3pauseretThe average shear stress versus shear displacement along the joint is plotted in Figure3.11,and the average normal displacement versus shear displacement is plotted in Figure3.12.These plots indicate that joint slip occurs for the prescribed properties and conditions.The loading slope in Figure3.11is initially linear and then becomes nonlinear as interface nodes begin to fail until a peak shear strength of approximately5.8MPa is reached.As indicated in Figure3.12,the joint begins to dilate when the interface nodes begin to fail in shear.。

flac入门指南—2

对于位移边界，通常情况下是设置固定边界，即约束各边界在法线方向不发生任何位移，采用fix命令进行设置，例如： fix x range x 49.9 50.1 (平面x=50处) 若在计算过程中，需对原先约束的平面接触约束，则采用free命令进行设置。对于速度边界，则相应可理解为间接位移边界，设置的边界节点的速度，将随着计算时步产生相应的位移，对于日常生产中的伺服控制以及一些常规的试验，如单轴三轴实验等可采用速度边界来进行较准确的位移控制和定位。
学习内容
• 1、基础知识
• • • •
2、建模、划分网格 3、本构模型及参数 4、边界条件、初始条件及加载 5、初始地应力的生成方法及初始平衡求解 • 6、求解及结果输出
1、基础知识
1.1 通用菜单(界面，菜单，术语) 1.2一个简单分析计算样例
建模、划分网格定义材料模型和参数初始条件及边界条件求解结果分析
需要指出：只有网格数之间存在整数倍的关系，才能采用attach 命令来进行连接，否则连接会失败或仅能连接部分节点。
1.2634e6
Gen zone brick size 4 4 4 Gen zone brick size 4 4 4 p0 4.1 0 0 p1 8 0 0 p2 4.1 4 0 p3 4.1 0 4 Gen merge 0.1
设置初始应力的弹塑性求解：
gen zon bri size 1 1 2 model mohr prop bulk 3e7 shear 1e7 c 10e3 f 15 ten 0 fix z ran z 0 fix x ran x 0 fix x ran x 1 fix y ran y 0 fix y ran y 1 ini dens 2000 ini szz -40e3 grad 0 0 20e3 ran z 0 2 ini syy -20e3 grad 0 0 10e3 ran z 0 2 ini sxx -20e3 grad 0 0 10e3 ran z 0 2 set grav 0 0 -10 solve

FLAC学习常用命令指南

常用命令指南1 命令指南这一节包括FLAC使用的所有命令的详细信息。

命令被描述为两个主要部分：首先，在节1.2中，这里有命令的概要汇总，它是以相关的模型函数来组织的。

准备一个输入DAT文件时建议先看一看这个命令汇总。

其次，在节1.3中，按字母顺序对所有的命令进行详细的描述。

节1.1中描述了一些共同的输入惯例和约定。

在Command and FISH Reference Summary 书中节1中同样提供了按字母顺序排例的命令汇总。

1.1 共同的惯例和约定1.1.1 语法FLAC可以用“交互”的方式进行操作（例如，通过键盘输入命令）或“文件控制”方式（例如，数据保存和读取在一个数据文件中，而这个文件保存在磁盘或硬盘中）。

无论哪种方式，解决一个问题的命令是相同的，数据输入的具体方法要看用户的偏爱。

所有的命令都是单词导向的，它包含一个主命令词，根据需要后面跟着一个或多个关键词和数值。

有些命令（例如PLOT）接受一个“开关”，它后面的关键字可以修改命令的动作。

每一个命令都有如下的格式：COM MAND key word value ... <key word value ... >命令关键词值… <关键词值…>所有的命令在输入行中逐字被输入。

你可以注意到只有少数几个字母是黑体，这表示要这个程序认识这个命令，最少要输入黑体字母。

同样地，小写字母显示的关键词也是逐字输入，只须要输入关键词的黑体字母长度即可。

如果用户需要，可以将命令和关键词写完整。

缺省情况下，单词是对大小写不敏感的--你可以使用大写字母，也可以使用小写字母。

许多关键词后有一系列的数字（值），这是关键词所要求的。

以黑体斜体表示的单词代表数值。

当单词以i,j,m或n开始时，后面应接整型数；否则，后面应接浮点型数（或小数）。

有时浮点型数中的小数点可以被省略，但是小数点不能出现在整型数中。

命令、关键词和数值可以通过任何多个空格分开或者通过下列的分界符分开：() , =你将可以看到在一些输入参数后有一些附加的符号。

FLACSlope 用户手册英文版

1FLAC/Slope1.1Introduction1.1.1OverviewFLAC/Slope is a mini-version of FLAC that is designed speciﬁcally to perform factor-of-safety calculations for slope-stability analysis.This version is operated entirely from FLAC’s graphical interface(the GIIC)which provides for rapid creation of models for soil and/or rock slopes and solution of their stability condition.FLAC/Slope provides an alternative to traditional“limit equilibrium”programs to determine factor of safety.Limit equilibrium codes use an approximate scheme—typically based on the method of slices—in which a number of assumptions are made(e.g.,the location and angle of interslice forces).Several assumed failure surfaces are tested,and the one giving the lowest factor of safety is chosen.Equilibrium is only satisﬁed on an idealized set of surfaces.In contrast,FLAC/Slope provides a full solution of the coupled stress/displacement,equilibrium and constitutive equations.Given a set of properties,the system is determined to be stable or unstable. By automatically performing a series of simulations while changing the strength properties(“shear strength reduction technique”—see Section1.5),the factor of safety can be found corresponding to the point of stability,and the critical failure(slip)surface can be located.FLAC/Slope does take longer to determine a factor of safety than a limit equilibrium program. However,with the advancement of computer processing speeds(e.g.,1GHz and faster chips), solutions can now be obtained in a reasonable time.This makes FLAC/Slope a practical alternative to a limit equilibrium program,and provides advantages over a limit equilibrium solution(e.g.,see Dawson and Roth,1999,and Cala and Flisiak,2001):1.Any failure mode develops naturally;there is no need to specify a range oftrial surfaces in advance.2.No artiﬁcial parameters(e.g.,functions for inter-slice force angles)need to begiven as input.3.Multiple failure surfaces(or complex internal yielding)evolve naturally,if theconditions give rise to them.4.Structural interaction(e.g.,rock bolt,soil nail or geogrid)is modeled realisti-cally as fully coupled deforming elements,not simply as equivalent forces.5.The solution consists of mechanisms that are feasible kinematically.(Notethat the limit equilibrium method only considers forces,not kinematics.)1.1.2Guide to the FLAC/Slope ManualThis volume is a user’s guide to FLAC/Slope.The following sections in the introduction,Sec-tions1.1.3through1.1.5,discuss the various features available in FLAC/Slope,outline the analysis procedure,and provide information on how to receive user support if you have any questions about the operation of FLAC/Slope.Also,in Section1.1.6,we describe the concept of mini-versions of FLAC and our plans for future mini-versions.Section1.2describes the step-by-step procedure to install and start up FLAC/Slope,and provides a tutorial(in Section1.2.2)to help you become familiar with its operation.We recommend that you run this tutorialﬁrst to obtain an overall understanding of the operation of FLAC/Slope.The components of FLAC/Slope are described separately in Section1.3.This section should be consulted for detailed descriptions on the procedures of operating FLAC/Slope.Several slope stability examples are provided in Section1.4.These include comparisons to limit analysis and limit-equilibrium solutions.FLAC/Slope uses the procedure known as the“strength reduction technique”to calculate a factor of safety.The basis of this procedure and its implementation in FLAC/Slope are described in Section1.5.1.1.3Summary of FeaturesFLAC/Slope can be applied to a wide variety of conditions to evaluate the stability of slopes and embankments.Each condition is deﬁned in a separate graphical tool.1.The creation of the slope boundary geometry allows for rapid generation of linear,nonlin-ear and benched slopes and embankments.The Bound tool provides separate generationmodes for both simple slope shapes and more complicated non-linear slope surfaces.Abitmap or DXF image can also be imported as a background image to assist boundarycreation.2.Multiple layers of materials can be deﬁned in the model at arbitrary orientations andnon-uniform yers are deﬁned simply by clicking and dragging the mouseto locate layer boundaries in the Layers tool.3.Materials and properties can be speciﬁed manually or from a database in the Materialtool.At present,all materials obey the Mohr-Coulomb yield model,and heterogeneousproperties can be assigned.Material properties are entered via material dialog boxes thatcan be edited and cloned to create multiple materials rapidly.4.With the Interface tool,a planar or non-planar interface,representing a joint,fault orweak plane,can be positioned at an arbitrary location and orientation in the model.Theinterface strength properties are entered in a properties dialog;the properties can bespeciﬁed to vary during the factor-of-safety calculation,or remain constant.5.An Apply tool is used to apply surface loading to the model in the form of either an arealpressure(surface load)or a point load.6.A water table can be located at an arbitrary location by using the Water tool;the water tabledeﬁnes the phreatic surface and pore pressure distribution for incorporation of effectivestresses and the assignment of wet and dry densities in the factor-of-safety calculation.7.Structural reinforcement,such as soil nails,rock bolts or geotextiles,can be installedat any location within the model using the Reinforce tool.Structural properties can beassigned individually for different elements,or groups of elements,through a propertiesdialog.Please be aware that FLAC/Slope is limited to slope conﬁgurations with sub-horizontal layering and no more than one interface.For analyses which involve multiple(and intersecting)interfaces and sub-vertical layering or weak planes,full FLAC should be used.1.1.4Analysis ProcedureFLAC/Slope is speciﬁcally designed to perform multiple analyses and parametric studies for slope-stability projects.The structure of the program allows different models in a project to be easily created,stored and accessed for direct comparison of model results.A FLAC/Slope analysis project is divided into four stages.The modeling-stage tool bars for each stage are shown and described below.Models StageEach model in a project is named and listed in a tabbed bar in the Models stage.Thisallows easy access to any model and results in a project.New models can be added tothe tabbed bar or deleted from it at any time in the project study.Models can also berestored(loaded)from previous projects and added to the current project.Note that theslope boundary is also deﬁned for each model at this stage.Build StageFor a speciﬁc model,the slope conditions are deﬁned in the Build stage.This includes:changes to the slope geometry,addition of layers,speciﬁcation of materials and weakplane(interface),application of surface loading,positioning of a water table and instal-lation of reinforcement.The conditions can be added,deleted and modiﬁed at any timeduring this stage.Solve StageIn the Solve stage,the factor-of-safety is calculated.The resolution of the numerical meshis selectedﬁrst(coarse,medium,ﬁne or user-speciﬁed),and then the factor-of-safetycalculation is performed.Different strength parameters can be selected for inclusion inthe strength reduction approach to calculate the safety factor.By default,the materialcohesion and friction angle are used.Plot StageAfter the solution is complete,several output selections are available in the Plot stagefor displaying the failure surface and recording the results.Model results are availablefor subsequent access and comparison to other models in the project.All models created within a project,along with their solutions can be saved,the projectﬁles can be easily restored and results viewed at a later time.1.1.5User SupportWe believe that the support that Itasca provides to code users is a major reason for the popularity of our software.We encourage you to contact us when you have a modeling question.We pro-vide a timely response via telephone,electronic mail or fax.General assistance in installation of FLAC/Slope on your computer,plus answers to questions concerning capabilities of the various features of the code,are provided free of charge.Technical assistance for speciﬁc user-deﬁned problems can be purchased on an as-needed basis.We can provide support in a more timely manner if you include an example FLAC/Slope model that illustrates your question.This can easily be done by including the project saveﬁle(i.e.,the ﬁle with the extension“*.PSL”)as an email attachment with your question.See Section1.3.2for a description of the“*.PSL”ﬁle.If you have a question,or desire technical support,please contact us at:Itasca Consulting Group,Inc.Mill Place111Third Avenue South,Suite450Minneapolis,Minnesota55401USAPhone:(+1)612-371-4711Fax:(+1)612·371·4717Email:software@Web:We also have a worldwide network of code agents who provide local technical support.Details may be obtained from Itasca.1.1.6FLAC Mini-VersionsThe basis for FLAC/Slope is FLAC,Itasca’s numerical modeling code for advanced geotechnical analysis of soil,rock and structural support in two dimensions.FLAC/Slope actually runs FLAC,and the GIIC limits access to only speciﬁc features in FLAC used for the slope stability calculations. That is why we call FLAC/Slope a mini-version of FLAC.We plan to develop several different mini-versions of FLAC for a variety of different geo-engineering applications.When you install FLAC/Slope,the full version of FLAC is also installed.If you wish,you may start-up FLAC and evaluate its operation and features.See the installation and start-up instructions given below in Section1.2.1.The solve facility is turned off in this evaluation version.If you decide to upgrade to the full FLAC,it is only necessary to upgrade your hardware lock to operate FLAC as well as FLAC/Slope.Then,the full power of FLAC will also be available to you.1.2Getting Started1.2.1Installation and Start-Up ProceduresSystem Requirements—To install and operate FLAC/Slope be sure that your computer meets the following minimum requirements:1.At least35MB of hard disk space must be available to install FLAC/Slope.We recom-mend that a minimum of100MB disk space be available to save model projectﬁles.2.For efﬁcient operation of FLAC/Slope,your computer should have at least128MB RAM.3.The speed of calculation is directly related to the clock speed of your computer.We rec-ommend a computer with at least a1GHz CPU for practical applications of FLAC/Slope.4.FLAC/Slope is a32-bit software product.Any Intel-based computer capable of runningWindows95or later is suitable for operation of the code.By default,plots from FLAC/Slope are sent directly to the Windows native printer.Plots can also be directed to the Windows clipboard,orﬁles encoded in PostScript,Enhanced Metaﬁle format, and several bitmap formats(PCX,BMP or JPEG).Instructions on creating plots are provided in Section1.3.11.Installation Procedure—FLAC/Slope is installed in Windows from the Itasca CD-ROM using standard Windows procedures.Insert the Itasca CD in the appropriate drive.The installation procedure will begin automatically,if the“autorun”feature on the drive is enabled.If not,enter “[cd drive]:\start.exe”on the command line to begin the installation process.The installation program will guide you through the installation.Make your selections in the dialogs that follow. Please note that the installation program can install all of Itasca’s software products.You must click on the FLAC box in the Select Components dialog in order to install FLAC/Slope on your computer(note that selecting the FLAC box is the correct choice for both FLAC and FLAC/Slope installations).*By default,the electronic FLAC/Slope manual will be copied to your computer during the installation of FLAC/Slope.(After FLAC has been selected in the Select Components dialog,the option not to install the manual can be set by using the Change button.)To use the electronic manual,click on the FLAC Slope Manual icon in the“Itasca Codes”group on the“Start”menu.All electronic volumes of the FLAC manual(including the FLAC/Slope manual)are PDFﬁles that require the Adobe Acrobat Reader(R)in order to be ers who do not have the Reader may install it from the Itasca CD.*The full version of FLAC will also be installed when FLAC/Slope is installed.You may start-up full FLAC and operate the code in GIIC mode to evaluate the features in the full version.Please note that the solve facility is turned off in the evaluation version.If you decide to upgrade to the full FLAC,it is only necessary to upgrade your hardware lock to operate FLAC as well as FLAC/Slope.The FLAC/Slope package can be uninstalled via the Add/Remove Programs icon in the Windows Control Panel.A default directory structure will be created when using the install program.The root directory is“\ITASCA”;the sub-directories and their contents are summarized in Table1.1and described below.Table1.1Contents of Itasca directories for FLAC/SlopeDirectory Sub-directory Section FilesFLACEXE executable codesFLAC SLOPE projectﬁles for examples in manualGUI Graphical User Interface—JA V A classﬁlesJRE JA V A runtime environmentMANUALS FLAC FLAC electronic manualSYSTEM hardware key drivers,FLAC.CFGUTILITY READMEﬁles,UPDATE.EXE•The“\FLAC”directory contains theﬁles related to the operation of FLAC/Slope.Thereare three sub-directories:“FLAC\EXE”contains the executable code that is loaded torun FLAC/Slope;“FLAC\FLAC SLOPE”contains the exampleﬁles described in thismanual;and“FLAC\GUI”containsﬁles used in the operation of the GIIC.•The“\JRE”directory contains the JA V A(TM)Runtime Environment(standard edition1.2.2)that is used for operating the GIIC.•The“\MANUALS\FLAC”directory contains the complete FLAC manual,which in-cludes the FLAC/Slope manual.•The“\SYSTEM”directory contains theﬁles related to the hardware lock.•The“UPDATE.EXE”ﬁle located in the“\UTILITY”directory is used to upgrade thehardware key if the full version of FLAC is purchased.Theﬁrst time you load FLAC/Slope you will be asked to specify a customer title.This title will appear on all hardcopy output plots generated by FLAC/Slope.The title information is written to aﬁle named“FLAC.CFG,”which is located in“ITASCA\SYSTEM.”If you wish to rename the customer title at a later time,delete“FLAC.CFG”and restart FLAC/Slope.Finally,be sure to connect the FLAC/Slope hardware key to your LPT1port before beginning operation of the code.Start-Up—The default installation procedure creates an“Itasca Codes”group with icons forFLAC/Slope and FLAC.To load FLAC/Slope,simply click on the FLAC/Slope icon.The code willstart-up and you will see the main window as shown in Figure1.1.The code name and current version number are printed in the title bar at the top of the window,and a main menu bar is positioned just below the title bar.The main menu contains File,Show, Tools,View and Help menus.Beneath the main menu bar is the Modeling Stage tool bar containing modeling-stage tabs for each of the stages:Models,Build,Solve and Plot.When you clickon a modeling-stage tab,a set of tools becomes available:these tools are used to create and run theslope-stability model.Separate sets of tools are provided for the models stage,the build stage,thesolve stage and the plot stage(as discussed previously in Section1.1.4).Figure1.1The FLAC/Slope main windowBeneath the Modeling Stage tool bar is the model-view pane.*The model-view pane shows agraphical view of the model.*If you are a user of full FLAC,you will also have access to a Console pane and Record pane.TheConsole pane shows text output and echos the FLAC commands that are created when operatingFLAC/Slope.This pane also allows command-line input(at the bottom of the pane).The Recordpane contains a list of all the FLAC commands,which can be exported to a dataﬁle for input intofull FLAC.The Console and Record panes are activated from the Show/Resources menu item.Directly above the model-view pane is a View tool bar.You can use the View tools to manipulate the model-view pane(e.g.,translate or rotate the view,increase or decrease the size of the view, turn on and off the model axes).The View tools are also available in the View menu. Whenever you start a new project,a Model Options dialog will appear,as shown in Figure1.1.You have the option to include different features,such as an interface(weak plane),a water table or reinforcement,in the model and specify the system of units for your project with this dialog.The menus and tools are described in detail in Section1.3.An overview of the FLAC/Slope operation is provided in the Help menu.This menu also contains a list of Frequently Asked Questions about FLAC/Slope and an index to all GIIC Helpﬁles.1.2.2A Simple TutorialThis section presents a simple tutorial to help you begin using FLAC/Slope right away.By working through this example,you will learn the recommended procedure to(1)deﬁne a project that includes different models,(2)build the slope conditions into each model,(3)calculate the factor of safety for each model,and(4)view the results.The example is a simple slope in a layered soil.Figure1.2illustrates the conditions of the slope. The purpose of the project is to evaluate the effect of the water table on the stability of the slope. The project consists of two models:one model with a water table and one without.In the following sections we discuss the four stages in the solution procedure for this problem.If you have not done so already,start up FLAC/Slope following the instructions in Section1.2.1. You will see the main FLAC/Slope window as shown in Figure1.1.You can now begin the tutorial.Figure1.2Conditions of the simple slopeDeﬁning the Project—We begin the project by checking the Include water table?box in the Model Options dialog.The water table tool will be made available for our analysis.We also select the SI: meter-kilogram-second system of units.Press OK to include these options in the project analysis. We now click on File/Save Project As...to specify a project title,a working directory for the project and a project saveﬁle.The Project Save dialog opens,as shown in Figure1.3,and we enter the project title and project saveﬁle names.The working directory location for the project is selected in this dialog.In order to change to a speciﬁc directory,we press?in this dialog.An Open dialog appears to allow us to change to the working directory of our choice.We specify a project saveﬁle name of“SLOPE”and note that the extension“.PSL”is assigned automatically—i.e.,the ﬁle“SLOPE.PSL”is created in our working directory.We click OK to accept these selections.Figure1.3Project Save dialogWe next click on the Models tool and enter the Models stage to specify a name for theﬁrst model in our project.We click on New and use the default model name Model1that appears in the New Model dialog.There will be two models in our project:Model1which does not contain a water table,and Model2which does.We will create Model2after we have completed the factor-of-safety calculation for Model1.(Note that,alternatively,we can create both modelsﬁrst before performing the calculation.)There are several types of model boundaries available to assist us in our model generation.For this tutorial,we select the Simple boundary button.When we press OK in the New Model dialog,an Edit slope parameters dialog opens and we enter the dimensions for our model boundary,as shown in Figure1.4.Note that we click on Mirror Layout to reverse the model layout to match that shown in Figure1.2.We click OK to view the slope boundary that we have created.We can either edit the boundary further or accept it.We press OK to accept the boundary for Model1.The layout for the Model1slope is shown in Figure1.5*.A tab is also created with the model name(Model1)at the bottom of the view.Also,note that an icon is shown in the upper-left corner of the model view indicating the direction and magnitude of the gravity vector.The project saveﬁle name,title and model name are listed in the legend to the model view. Additional information will be added as we build the model.*We have increased the font size of the text in the model view.We click on the File/Preference Settings...menu item and change the font size to16in the Preference settings dialog.Figure1.4Edit Slope Parameters dialogFigure1.5Model1layoutBuilding the Model—We click on the Build tool tab to enter the Build stage and begin adding the slope conditions and materials to Model1.Weﬁrst deﬁne the two soil layers in the model.By clicking on the Layers button we open the Layers tool.(See Figure1.6.)A green horizontal line with square handles at each end is shown when we click on the mouse inside the slope boundary;this line deﬁnes the boundary between two layers.We locate this line at the level y=9m by right-clicking on one of the end handles and entering9.0in the Enter vertical level dialog.We press OK in the dialog and then OK in the Layers tool to create this boundary between the two layers.The result is shown in Figure1.7.Figure1.6Layers toolFigure1.7Two layers created by the Layers toolThere are two materials in the slope.These materials are created and assigned to the layers using the Material tool.After entering this tool,weﬁrst click on the Create button which opens the Deﬁne Material dialog.We create the two materials,upper soil and lower soil,and assign the densities and strength properties using this dialog.(Note that after one material is created,it can be cloned using the Clone button,and then the properties can be modiﬁed to create the second material.)The properties assigned for the upper soil material are shown in Figure1.8.(A Class,or classiﬁcation name,is not speciﬁed;this is useful if materials are stored in a database—see Section1.3.5.)Figure1.8Properties input in the Deﬁne Material dialog for upper soilAfter the materials are created,they are assigned to the two layers.We highlight the material in the List pane and then click on the model view inside the layer we wish to assign the material.The material will be assigned to this layer,and the name of the material will be shown at the position that we click on the mouse inside this layer.The result after both materials are assigned is shown in Figure1.9.We press OK to accept these materials in Model1.Figure1.9Materials assigned to the two layers in the Material toolCalculating a Factor of Safety—We are now ready to calculate the factor of safety.We click on the Solve tool tab to enter the factor-of-safety calculation stage.When we enter this stage,we must ﬁrst select a numerical mesh for our analysis.We choose a“coarse-grid”model by pressing the Coarse button,and the grid used for the FLAC solution appears in the model view.See Figure1.10.Figure1.10Coarse-grid for Model1We now press the Solve FoS button to begin the calculation.A Factor of Safety parameters dialog opens(Figure1.11),we accept the default solution parameters,and press OK.FLAC/Slope beginsthe calculation mode,and a Model cycling dialog provides a status of the solution process.When the calculation is complete,the calculated factor of safety is printed;in this case the value is1.68.Figure1.11Factor of Safety parameters dialogViewing the Results—We now click on the Plot tool tab to view the results.An fc button is shown,corresponding to the solution conditions(coarse grid,friction angle and cohesion included in the calculation).When we click on this button,we view the failure plot for this model,as shown in Figure1.12.Figure1.12Failure plot for coarse-grid Model1This plot shows the failure surface that develops for these model conditions(delineated by the shear strain-rate contours and velocity vectors).The value for factor of safety is also printed in the plot legend.Performing Multiple Analyses—We wish to compare this result to the case with a water table. We click on the Models tool tab to create the second model.We will start with Model1conditions by clicking on the Clone button.An Input dialog will appear again,but this time the default model name is Model2.We accept this name by pressing OK.A Model2tab is now shown at the bottom of the view.All the model conditions from Model1have been copied into Model2.The only remaining condition to add is the water table.We go to the Build stage and click on the Water button.A blue horizontal line with square handles is shown in the Water tool.We position this line to match the location of the water table as shown in Figure1.2.The line can either be re-positioned by left-clicking the mouse on the line and dragging the line to the water-table location,or by right-clicking the mouse on the line,which opens a dialog to specify coordinates of the water table.We deﬁne the water table by four points at coordinates:(0,10),(15,8),(30,3)and(40,3).The result is shown in Figure1.13.Figure1.13Positioning water table in the Water toolWe are now ready to solve Model2,so we go to the Solve stage,select the coarse-grid model and press the Solve FoS button.We follow the same procedure as before to determine the factor of safety.A factor of1.53is shown when the calculation stops.We now go to the Plot stage to produce the failure plot for this model.The result is shown in Figure1.14.Note that the water table is added to this plot by opening a Failure plot items dialog via the Items button.The results for Model2can easily be compared to those for Model1by clicking on the model-name tabs at the bottom of the model view.Figure1.14Failure plot for coarse-grid Model2Making Hardcopy Plots—Several different printer formats are available to create plots from FLAC/Slope.We click on the Setup button in the Plot tool bar to open a Print setup dialog,as shown in Figure1.15.Figure1.15Print setup dialogFor example,we have two choices if we wish to create a plot in an enhanced metaﬁle format for insertion into a Microsoft Word document:(1)We can click on the Enhanced Metafile radio button.We select the name of theﬁle and thedirectory in which to save theﬁle by using the File radio button.As shown in theﬁgure,we save the failure plot to aﬁle named“MODEL2.EMF.”We press OK to save theseprinter settings.Then,we press Print in the Plot tool to send the plot to thisﬁle.(2)Alternatively,we can copy the plot to the clipboard,by clicking the Clipboard button.Wepress OK to save this setting.Then,press Print in the Plot tool to send the plot to theclipboard andﬁnally paste the plot directly into the Word document.The plot is shown in Figure1.16.Note that hardcopy plots are formatted slightly differently from the screen plots.Figure1.16Hardcopy plot for Model2resultThis completes the simple tutorial.We recommend that you try additional variations on this project to help increase your understanding.For example,if you wish to evaluate the effect of zoning on the calculated safety factor,return to the Solve stage for Model1and click on the Medium button.This will create aﬁner mesh than the coarse mesh model.After solving for the factor of safety,a new plot button will be added in the Plot tool bar for Model1.You can then compare this result for a medium mesh directly with the coarse mesh result by clicking on the plot buttons.See Section1.3 for more information on the components of FLAC/Slope and recommended procedures to perform slope-stability calculations.。

flac主要操作命令

Brick 维数0？？填充？？ANSYS到FLAC怎么到得??Flac3d命令大小写一样，命令格式如下：command <keyword value> [keyword value]Plot set magnification 1.5(就是视图放大1.5倍，但实际尺寸不变)。

Creat为plot命令的子命令，功能是创建一个新视图，并设为当前视图，可简写为CR。

Contour关键字为在当前视图中显示等值线图，可简写为CON.Disp关键字指定为位移量等值线图。

bcontour关键字为绘制指定区域的等直线图szz为垂直应力σzzplane为设置一个剖平面,剖面参数由后面关键字确定，简写为P。

dip关键字尾剖面的倾角，x-y平面其角度为0. dd为剖面的倾向，y轴方向为0.origin关键字为剖面中的一点，可简写为o。

boundary 关键字尾在视图中增加面得边界线框，可简写为bo.behind关键字为当前视图剖平面后面，可简写为be.GravV视图的一个剖面上的垂直应力σzz等值线图Create gravVSet plane dip =90 dd=0 origin =3,4,0Add boundary behindAdd bcontour szz planeAdd axes blackshow沟渠开挖Property cohesion=1e3 tension=1e3Model null range x=2,4 y=2,6 z=5,10Set largeInitial xdisplacement=0 ydisplacement=0 zdisplacement=0Step 2000Plot create dispcontPlot copy gravv dispcont settingsPlot add contour disp plane behind shade onPlot add axesPlot showFLAC的文件格式⏹项目文件(*.prj)–这种文件是一个ASCⅡ文件，包含用来描述保存项目时GIIC所处的状态，还包括一个到和项目相关的FLAC保存文件“.SA V”的链接。

Flac3D使用手册

Flac3D使⽤⼿册3INTERFACES3.1General CommentsThere are several instances in geomechanics in which it is desirable to represent planes on which sliding or separation can occur—for example:1.joint,fault or bedding planes in a geologic medium;2.an interface between a foundation and the soil;3.a contact plane between a bin or chute and the material that it contains;4.a contact between two colliding objects;and5.a planar“barrier”in space,which represents a?xed,non-deformable boundaryat an arbitrary position and orientation.FLAC3D provides interfaces that are characterized by Coulomb sliding and/or tensile and shear bonding.Interfaces have the properties of friction,cohesion,dilation,normal and shear stiffnesses, tensile and shear bond strength.Although there is no restriction on the number of interfaces or the complexity of their intersections,it is generally not reasonable to model more than a few simple interfaces with FLAC3D because it is awkward to specify complicated interface geometry.Theprogram3DEC(Itasca1998)is speci?cally designed to model many interacting bodies in three dimensions;it should be used instead of FLAC3D for the more complicated interface problems. Interfaces may also be used to join regions that have different zone sizes.In general,the ATTACH command should be used to join grids together.However,in some circumstances it may be more convenient to use an interface for this purpose.In this case,the interface is prevented from sliding or opening because it does not correspond to any physical entity.3.2FormulationFLAC 3D represents interfaces as collections of triangular elements (interface elements),each of which is de?ned by three nodes (interface nodes).Interface elements can be created at any location in space.Generally,interface elements are attached to a zone surface face;two triangular interface elements are de?ned for every quadrilateral zone face.Interface nodes are then created automatically at every interface element vertex.When another grid surface comes into contact with an interface element,the contact is detected at the interface node,and is characterized by normal and shear stiffnesses,and sliding properties.Each interface element distributes its area to its nodes in a weighted fashion.Each interface node has an associated representative area.The entire interface is thus divided into active interface nodes representing the total area of the interface.Figure 3.1illustrates the relation between interface elements and interface nodes and the representative area associated with an individual node.elementinterfaceFigure 3.1Distribution of representative areas to interface nodesIt is important to note that interfaces are one-sided in FLAC 3D .(This differs from the formulation of two-sided interfaces in two-dimensional FLAC (Itasca 2000).)It may be helpful to think of FLAC 3D interfaces as “shrink-wrap”that is stretched over the desired surface,causing the surface to become sensitive to interpenetration with any other face with which it may come into contact.The fundamental contact relation is de?ned between the interface node and a zone surface face,also known as the target face .The normal direction of the interface force is determined by the orientation of the target face.During each timestep,the absolute normal penetration and the relative shear velocity are calculated for each interface node and its contacting target face.Both of these values are then used by the interface constitutive model to calculate a normal force and a shear-force vector.The constitutive model is de?ned by a linear Coulomb shear-strength criterion that limits the shear force acting at an interface node,normal and shear stiffnesses,tensile and shear bond strengths,and a dilation angle that causes an increase in effective normal force on the target face after the shear-strength limit is reached.By default,pore pressure is used in the interface effective stress calculation.This option can be activated/deactivated using the command INTERFACE i effective=on/off.Figure3.2 illustrates the components of the constitutive model acting at interface node(P).Figure3.2Components of the bonded interface constitutive modelThe normal and shear forces that describe the elastic interface response are determined at calculation time(t+ t)using the following relations.F(t+ t)n=k n u n A+σn A(3.1)F(t+ t) si =F(t)si+k s u(t+(1/2) t)siA+σsi Awhere F(t+ t)n is the normal force at time(t+ t)[force];F(t+ t)si is the shear force vector at time(t+ t)[force];u n is the absolute normal penetration of the interface nodeinto the target face[displacement];u si is the incremental relative shear displacement vector[displacement];σn is the additional normal stress added due to interface stressinitialization[force/displacement];k n is the normal stiffness[stress/displacement];k s is the shear stiffness[stress/displacement];σsi is the additional shear stress vector due to interface stressinitialization;andA is the representative area associated with the interface node[length2].The inelastic interface logic works in the following way:(1)Bonded interface—The interface remains elastic if stresses remain below the bond strengths:there is a shear bond strength as well as a tensile bond strength.The nor-mal bond strength is set using the tension interface property keyword.The command INTERFACE n prop sbratio=sbr sets the shear bond strength to sbr times the normal bond strength.The default value of sbratio(if not given)is100.0.The bond breaks if either the shear stress exceeds the shear strength,or the tensile effective normal stress exceeds the normal strength.Note that giving sbratio alone does not cause a bond to be established; the tensile bond strength must also be set.(2)Slip while bonded—An intact bond,by default,prevents all yield behavior(slip and separation).There is an optional property switch(bslip)that causes just separationto be prevented if the bond is intact(but allows shear yield,under the control of the friction and cohesion parameters,using abs(F n)as the normal force).The command to allow/disallow slip for a bonded interface segment isINTER n PROP bslip=onbslip=offThe default state of bslip(if not given)is off.(3)Coulomb sliding—A bond is either intact or broken.If it is broken,then the behaviorof the interface segment is determined by the friction and cohesion(and of course the stiffnesses).This is the default behavior,if bond strengths are not set(zero).A broken bond segment cannot take effective tension(which may occur under compressive normal force,if the pore pressure is greater).The shear force is zero(for a non-bonded segment)if the effective normal force is tensile or zero.The Coulomb shear-strength criterion limits the shear force by the following relation.F smax=cA+tanφ(F n?pA)(3.2)where c is the cohesion[stress]along the interface;φis the friction angle[degrees]of the interface surface;andp is pore pressure(interpolated from the target face),provided the keywordeffective=off has not been issued for the interface.If the criterion is satis?ed(i.e.,if|F s|≥F smax),then sliding is assumed to occur,and |F s|=F smax,with the direction of shear force preserved.During sliding,shear displacement may cause an increase in the effective normal stress on the joint,according to the relation:σn:=σn+|F s|o?F smaxAk s tanψk n(3.3)whereψis the dilation angle[degrees]of the interface surface;and|F s|o is the magnitude of shear force before the above correction is made.On printout(PRINT interface n prop tens),the value of tension denotes if a bond is intact or broken (or not set)—non-zero or zero,respectively.The normal and shear forces calculated at the interface nodes are distributed in equal and opposite directions to both the target face and the face to which the interface node is connected(the host face). Weighting functions are used to distribute the forces to the gridpoints on each face.The interface stiffnesses are added to the accumulated stiffnesses at gridpoints on both sides of the interface,in order to maintain numerical stability.Interface contacts are detected only at interface nodes,and contact forces are transferred only at interface nodes.The stress state associated with a node is assumed to be uniformly distributed over the entire representative area of the node.Interface properties are associated with each node; properties may vary from node to node.By default,the effect of pore pressure is included in the interface calculation by using effective stress as the basis for the slip condition.(The interface pore pressure is interpolated from the target face.)This applies either in CONFIG?uid mode,or if pore pressures are assigned with the WATER table or INITIAL pp command without specifying CONFIG?uid.The user can switch options for interface i by using the command INTERFACE i effective=on/off.By default,in the FLAC3D logic,?uid?ow—saturated or unsaturated—is carried across an interface,provided the interface keyword maxedge is not used for that particular interface.The permeable interface option can be deactivated/reactivated for interface i by using the command INTERFACE i perm=on/off.Note that if the keyword maxedge is used,and perm is on for a particular interface,a warning is issued to inform the user that this interface will be considered as impermeable to?uid?ow.(Note that, for?uid?ow calculation only,a mechanical model must be present.Also,the command CYCLE 0with SET mech on should be used to initialize the weighting factors used to transfer?uid?ow information across the interface.)No pressure drop normal to the joint and no in? uence of normal displacement on pore pressure are calculated.Also,?ow of?uid along the interface is not modeled.3.3Creation of Interface GeometryInterfaces are created with the INTERFACE command.For cases in which an interface is required between two separate grids in the model,the command INTERFACE i face range...should be used to attach an interface to one of the grid surfaces.This command generates interface elements for interface i along all surface zone faces with a center point that fall within a speci?ed range.Any surfaces on which an interface is to be created must be generated initially with some separation between the adjacent surfaces;it must be possible to specify an existing surface in order to create the interface elements. (Also,a gap must be speci?ed between the two grids because the grid generator will automatically merge surface gridpoints if they are created at the same location in space.)By default,two interface elements are created for each zone face.The number of interface elements can be increased by using the command INTERFACE i maxedge v.*This causes all interface elements with edge lengths larger than v to subdivide into smaller elements until their lengths are smaller than v.This command can be used to increase the resolution and decrease arching of forces in portions of a model that have large contrasts in zone size across an interface.The following rules should be followed when using interface elements in FLAC3D.1.If a smaller surface area contacts a larger surface area(e.g.,a small block restingon a large block),the interface should be attached to the smaller region.2.If there is a difference in zone density between two adjacent grids,the interfaceshould be attached to the grid with the greater zone density(i.e.,the greaternumber of zones within the same area).3.The size of interface elements should always be equal to or smaller than thetarget faces with which they will come into contact.If this is not the case,theinterface elements should be subdivided into smaller elements.4.Interface elements should be limited to grid surfaces that will actually comeinto contact with another grid.A simple example illustrating the procedure for interface creation is provided in Example3.1.The example is a block specimen containing a single joint dipping at an angle of45?.Example3.1Creating a model with a dipping joint;Create Basegen zone brick size333&p0(0,0,0)p1(3,0,0)p2(0,3,0)p3(0,0,1.5)&p4(3,3,0)p5(0,3,1.5)p6(3,0,4.5)p7(3,3,4.5)group Base*Note that if CONFIG?uid is invoked,and perm is on for a particular interface,specifying maxedge for that interface will automatically make it impermeable.Do not specify maxedge if?ow across the interface is desired.;Create Top-1unit high for initial spacinggen zone brick size333&p0(0,0,2.5)p1(3,0,5.5)p2(0,3,2.5)p3(0,0,7)&p4(3,3,5.5)p5(0,3,7)p6(3,0,7)p7(3,3,7)group Top range group Base not;;Create interface elements on the top surface of the baseinterface1face range plane norm(-1,0,1)origin(1.5,1.5,3)dist0.1;plot create view_intplot add surfaceplot add interface redplot showpause;;Lower top to complete geometryini z add-1.0range group Topsave int.savFigure3.3shows the grid before the interface is created.Two sub-grid groups are de?ned:a Base grid,and a Topgrid.Figure3.4shows the model with the interface elements attached to the Base grid.Figure3.5shows the?nal geometry with the sub-grids moved together.A uniaxial compression test with this model is described later in Section3.4.3.Figure3.3Initial geometry before creation of the interfaceFigure3.4Interface elements addedFigure3.5Final geometry3.4Choice of Material PropertiesAssignment of material properties(particularly stiffnesses)to an interface depends on the way in which the interface is used.Three possibilities are common.The interface may be:1.an arti?cial device to connect two sub-grids together;2.a real interface that is stiff compared to the surrounding material,but which canslip and perhaps open in response to the anticipated loading.(This case alsoencompasses the situation in which stiffnesses are unknown or unimportant,but where slip and/or separation will occur—e.g.,?ow of frictional materialin a bin);or3.a real interface that is soft enough to in?uence the behavior of the system(e.g.,a joint with soft clay?lling or a dyke containing heavily fractured material).These cases are examined in detail.3.4.1Interface Used to Join Two Sub-gridsIf possible,sub-grids should be joined with the ATTACH command.It is more computationally-ef?cient to use ATTACH than INTERFACE to join sub-grids.See Section3.2.1.2in the User’s Guide, for a description of,and restrictions on,the ATTACH command.Under some circumstances it may be necessary to use an interface to join two sub-grids.This type of interface is assigned high strength properties with the INTERFACE command,thus preventing any slip or separation.(This is the equivalent ofa“glued”interface in FLAC.)Shear and normal stiffnesses must also be provided;values of friction and cohesion are not needed.It is tempting (particularly for people familiar with?nite element methods)to give a very high value for these stiffnesses to prevent movement on the interface.However,FLAC3D does“mass scaling”(see Section1.1.2.6)based on stiffnesses—the response(and solution convergence)will be very slow if very high stiffnesses are speci?ed.It is recommended that the lowest stiffness consistent with small interface deformation be used.A good rule-of-thumb is that k n and k s be set to ten times the equivalent stiffness of the stiffest neighboring zone.The apparent stiffness(expressed in stress-per-distance units)of a zone in the normal direction ismax K+43Gz min(3.4)where K&G are the bulk and shear moduli,respectively;andz min is the smallest width of an adjoining zone in the normal direction—seeFigure3.6.The max[]notation indicates that the maximum value over all zones adjacent to the interface is to be used(e.g.,there may be several materials adjoining the interface).InterfaceFigure3.6Zone dimension used in stiffness calculationTo illustrate the approach,consider Figure3.7,in which two sub-grids of unequal zoning are joined by the commands in Example3.2and are loaded by a pressure on the left-hand part of the upper surface:Example3.2Joining two sub-gridsgen zone brick size444p00,0,0p14,0,0p20,4,0p30,0,2gen zone brick size884p00,0,3p14,0,3p20,4,3p30,0,5inter1face range z 2.9,3.1inter1prop kn300e9ks300e9tens1e10SBRATIO=1ini z add-1.0range z 2.9,5.1model elasprop bulk8e9shear5e9fix z range z-.1.1fix x range x-.1.1fix x range x 3.9 4.1fix y range y-.1.1fix y range y 3.9 4.1apply szz-1e6range z 3.9 4.1x0,2y0,2hist unbalsolvesave join.savThe value of(K+4G/3)is15GPa,and the minimum zone size adjacent to the interface is 0.5m.Hence,we choose both shear stiffness and normal stiffness to be150×109/0.5—i.e., k n=k s=3×1011Pa/m.The resulting contours of z-displacement are shown in Figure3.8.Compare this result to that for a single grid,shown in Figure3.7in the User’s Guide.This plot is at the same scale and contour intervals as Figure3.8.The two plots are almost identical,which indicates that the interface does not affect the behavior to any great extent.The prescription given in Eq.(3.4)is reasonable if the materials on the two sides of the interface are similar,and variations ofstiffness occur only in the lateral directions.However,if the material on one side of the interface is much stiffer than that on the other,then Eq.(3.4)should be applied to the softer side.In this case,the deformability of the whole system is dominated by the soft side;making the interface stiffness ten times the soft-side stiffness will ensure that the interface has minimal in?uence on system compliance.Figure3.7Two unequal sub-grids joined by an interfaceFigure3.8Vertical displacement contours—two joined grids3.4.2Real Interface—Slip and Separation OnlyIn this case,we simply need to provide a means for one sub-grid to slide and/or open relative to another sub-grid.The friction(and perhaps cohesion,dilation,and tensile strength)is important, but the elastic stiffness is not.The approach of Section3.4.1is used here to determine k n and k s. However,the other material properties are given real values(see Section3.4.3for advice on choice of properties).As an example,we can allow slip in a bin-?ow problem,as shown in Figure3.9,corresponding to the data?le inExample3.3.The bond strengths are not set(i.e.,they default to zero);the interface stiffnesses are set to approximately ten times the equivalent stiffness of the neighboring zones.Figure3.9Flow of frictional material in a“bin”Example3.3Slip in a bin-?ow problem;Create Material Zonesgen zone brick size555&p0(0,0,0)p1(3,0,0)p2(0,3,0)p3(0,0,5)&p4(3,3,0)p5(0,5,5)p6(5,0,5)p7(5,5,5) gen zone brick size555p0(0,0,5)edge 5.0 group Material;Create Bin Zonesgen zone brick size155&p0(4,1,0)p1add(3,0,0)p2add(0,3,0)&p3add(2,0,5)p4add(3,6,0)p5add(2,5,5)&p6add(3,0,5)p7add(3,6,5)gen zone brick size155&p0(6,1,5)p1add(1,0,0)p2add(0,5,0)&p3add(0,0,5)p4add(1,6,0)p5add(0,5,5)&p6add(1,0,5)p7add(1,6,5)gen zone brick size515&p0(1,4,0)p1add(3,0,0)p2add(0,3,0)&p3add(0,2,5)p4add(6,3,0)p5add(0,3,5)&p6add(5,2,5)p7add(6,3,5)gen zone brick size515&p0(1,6,5)p1add(5,0,0)p2add(0,1,0)&p3add(0,0,5)p4add(6,1,0)p5add(0,1,5)&p6add(5,0,5)p7add(6,1,5)group Bin range group Material not;Create named range synonymsrange name=Bin group Binrange name=Material group Material;Assign models to groupsmodel mohr range Materialmodel elas range Bin;Create interface elementsint1face ran plane ori(4,0,0)nor(-5,0,2)dist0.01z(0,5)y(1,6) int2face ran plane ori(0,4,0)nor(0,-5,2)dist0.01z(0,5)x(1,6) int1face ran x 5.9 6.1y16z510int2face ran x16y 5.9 6.1z510int1maxedge0.55int2maxedge0.55;Move bin toward materialini x add-1.0range Binini y add-1.0range Bin;Assign propertiesprop shear1e8bulk2e8fric30range Materialprop shear1e8bulk2e8range Binini den2000int1prop ks2e9kn2e9fric15int2prop ks2e9kn2e9fric15;Assign Boundary Conditionsfix x range x-0.10.1any x 5.9 6.1anyfix y range y-0.10.1any y 5.9 6.1anyfix z range z-0.10.1Bin;Monitor historieshist unbalhist gp zdisp(6,6,10)hist gp zdisp(0,0,10)hist gp zdisp(0,0,0);Settingsset largeset grav0,0,-10;Cyclingstep4000save bin.sav3.4.3All Properties Have Physical Signi?canceIn this case,properties should be derived from tests on real joints*(suitably scaled to account for size effect),or from published data on materials similar to the material being modeled.However, the comments of Section3.4.1also apply here with respect to the maximum stiffnesses that are reasonable to use.If the physical normal and shear stiffnesses are less than ten times the equivalent stiffness of adjacent zones,then there is no problem in using physical values.If the ratio is much more than ten,the solution time will be signi?cantly longer than for the case in which the ratio is limited to ten,without much change in the behavior of the system.Serious consideration should be given to reducing supplied values of normal and shear stiffnesses to improve solution ef?ciency. There may also be problems with interpenetration if the normal stiffness,k n,is very low.A rough estimate should be made of the joint normal displacement that would result from the application of typical stresses in the system(u=σ/k n).This displacement should be small compared to a typical zone size.If it is greater than,say,10%of an adjacent zone size,then there is either an error in one of the numbers,or the stiffness should be increased if calculations are to be done in large-strain mode.Joint properties are conventionally derived from laboratory testing(e.g.,triaxial and direct shear tests).These tests can supply physical properties for joint friction angle,cohesion,dilation angle, and tensile strength,as well as joint normal and shear stiffnesses.The joint cohesion and friction angle correspond to the parameters in the Coulomb strength criterion?described in Section3.2. Values for normal and shear stiffnesses for rock joints typically can range from roughly10to100 MPa/m for joints with soft clay in-?lling,to over100GPa/m for tight joints in granite and basalt. Published data on stiffness properties for rock joints are limited;summaries of data can be found in Kulhawy(1975),Rosso(1976),and Bandis et al.(1983).Approximate stiffness values can be back-calculated from information on the deformability and joint structure in the jointed rock mass and the deformability of the intact rock.If the jointed rock mass is assumed to have the same deformational response as an equivalent elastic continuum,then relations can be derived between jointed rock properties and equivalent continuum properties. For uniaxial loading of rock containing a single set of uniformly spaced joints oriented normal to the direction of loading,the following relation applies.1=1r +1n(3.5)*“Joint”is used here as a generic term.The Coulomb yield surface provides a reasonable approximation for joint strength for most engi-neering calculations.More complex joint models are available which include,for example,effects of continuous yielding and displacement weakening.For analysis with other joint models,the user is referred to UDEC(Itasca1996).ork n=E E rs(E r?E)(3.6)where E=rock mass Young’s modulus;E r=intact rock Young’s modulus;k n=joint normal stiffness;ands=joint spacing.A similar expression can be derived for joint shear stiffness:k s=G G rs(G r?G)(3.7)where G=rock mass shear modulus;G r=intact rock shear modulus;andk s=joint shear stiffness.The equivalent continuum assumption,when extended to three orthogonal joint sets,produces the following relations:E i=1r+1i ni1(i=1,2,3)(3.8)G ij=1G r+1s i k si+1s j k sj1(i,j=1,2,3)(3.9)Several expressions have been derived for two-and three-dimensional characterizations and multiple joint sets.References for these derivations can be found in Singh(1973),Gerrard(1982(a)and (b)),and Fossum(1985).Published strength properties for joints are more readily available than stiffness properties.Sum-maries can be found,for example,in Jaeger and Cook(1979),Kulhawy(1975),and Barton(1976). Friction angles can vary from less than10?for smooth joints in weak rock,such as tuff,to over 50?for rough joints in hard rock,such as granite.Joint cohesion can range from zero to values approaching the compressive strength of the surrounding rock.It is important to recognize that joint properties measured in the laboratory typically are not rep-resentative of those for real joints in the?eld.Scale dependence of joint properties is a major question in rock mechanics.Often,the only way to guide the choice of appropriate parameters is by comparison to similar joint properties derived from?eld tests.However,?eld test observations are extremely limited.Some results are reported by Kulhawy(1975).The following example illustrates an application of the interface logic to simulate the physical response of a rock joint subjected to normal and shear loading.The model represents a direct shear test,which consists of a single horizontal joint that is?rst subjected to a normal con?ning stress, and then to a unidirectional shear displacement.Figure3.10shows the model.Figure3.10Direct shear test modelFirst,a normal stress of10MPa is applied that is representative of the con?ning stress acting on the joint.A horizontal velocity is then applied to the top sub-grid to produce a shear displacement along the interface.For demonstration purposes,we only apply a small shear displacement of less than2mm to this model.The average normal and shear stresses,and normal and shear displacements along the joint,are measured with a FISH function.With this information we can determine the shear strength and dilation that are produced.The data?le for this test is contained in Example3.4.Example3.4Direct shear testtitleDirect shear testgen zone brick size12110p0406p11606p2416p34011 gen zone brick size20110p12000p2010p3005range name bot z05range name top z611interface1face range z5int1prop ks4e4kn4e4fric30dil6;tension1e10bslip=onini z add-1.0range top;plo surf lorange interface white axes blackmodel eprop bulk45e3sh30e3fix x y z range z0fix x range x0fix x range x20apply nstress-10range z10step0plot contour szz interface white axes blacksolvesave dsta.savini xvel5e-7range topfix xvel range topdef ini_jdispvalnd=0.0count=0.0p_in=i_node_head(i_head)loop while p_in#nullif in_ztarget(p_in)#null thenvalnd=valnd+in_pen(p_in)count=count+ 1.0end_ifp_in=in_next(p_in)end_loopnjdisp0=valnd/countendini_jdispdef sstavvalns=0.0valss=0.0valsd=0.0valnd=0.0count=0.0p_in=i_node_head(i_head)loop while p_in#nullif in_ztarget(p_in)#null thenvalns=valns+in_nstr(p_in)*in_area(p_in) valss=valss+in_sstr(p_in,1)*in_area(p_in) valsd=valsd+in_sdisp(p_in,1)valnd=valnd+in_pen(p_in)count=count+ 1.0end_ifp_in=in_next(p_in)end_loopsstav=valss/(12.0*1.0)nstav=valns/(12.0*1.0)sjdisp=valsd/countnjdisp=valnd/count-njdisp0endhist ns1hist sstav nstav sjdisp njdispini xdis0ydis0zdis0step2500save dst.savplot his-1vs-3pauseplot his-4vs-3pauseretThe average shear stress versus shear displacement along the joint is plotted in Figure3.11,and the average normal displacement versus shear displacement is plotted in Figure3.12.These plots indicate that joint slip occurs for the prescribed properties and conditions.The loading slope in Figure3.11is initially linear and then becomes nonlinear as interface nodes begin to fail until a peak shear strength of approximately5.8MPa is reached.As indicated in Figure3.12,the joint begins to dilate when the interface nodes begin to fail in shear.。

FLAC说明书翻译

FLAC/slope1.1 绪论1.1.1 总言FLAC/slope是FLAC的一个小版本，专门用来进行边坡稳定行分析中安全系数的计算。

这个版本完全以FLAC图形界面（GIIC）运行，图形界面提供了土和/或岩坡快速模型建立和它们稳定性条件的解答。

FLAC/slope提出了一种有别于传统的“有界平衡法”的新方法来确定安全系数。

有限平衡编码用了一种近似的放案。

特征是切片法的基础上，它事业了大量假设（例如定位和angle of interstice forces）。

测定一些假定的弱面，选种安全性最低的弱面，平衡仅仅是在一组理想化面上得到满足。

比较而言，FLAC/slope提高了一整套成对应力位移，平衡和结构方程的解决方法。

给定一组属性，系统会判定它是稳定还是不稳定。

改变力学属性（抗剪强度规约技术见1.5）的同时自动进行一系列的模拟。

通过对应点的平衡发现安全系数，定位临界滑落面。

FLAC/slope确定一个安全系数要比有限平衡法花的时间多。

然而，随着计算机运行速度的提高（例如IGHZ或者更快的芯片）可以在一个合理的时间内得到答案。

这使得FLAC/slope比有限平衡法更先进（例如：见Dawson and Roth,1999,and cala and Flssiak,2001）成为一个比有限平衡法实用的选择。

1. 任何错误的摸索自然发展；没有必要预先说明许多试验面。

2. 不需要输入给定的人工参数（例如functions for inter-slice force angles）3. 如果条件使滑落面（或复杂的内部屈服）发生，它们会成倍的自动发展。

4. 结构的相互作用（例如rock bolt,soil nail or geogrid）被现实的模拟，以全部成对变形因素，而不是以相应的力简单模拟。

5. 方法包括使运动可行的机构（注意：有限平衡法只考虑力，没有考虑运动）1.1.2 怎样使用FLAC/slope手册这本书是拥护使用FLAC/slope的指南。

FLAC3D渗流说明书(中文版)

FLAC3D流固耦合（手册翻译）1.1简介FLAC3D通过具有渗流性的实体（比如土）来模拟流体的流动。

流动模型的建立可以独立于力学计算而自动完成，或者说可以与力学模型同时建立，这样就可以考虑流体与土体之间的相互作用。

流固耦合的一种类型是“固结”，即:空隙水压力逐渐消散而导致土体的沉降。

这个过程包括两种力学反映：一，空隙水压的改变导致有效应力的变化，这将影响到土体的力学反映（如：有效应力的减小可能导致塑性区的产生）；二，力学实体中某一区域的流动会随着空隙水压的改变而改变。

该程序可以计算完全饱和情况下的流动，也可以模拟具有自由水面的流动。

模拟具有自由水面的流动时，自由水面以上的部分空隙水压等于0，气相将不参与计算。

对于不考虑毛细水压力颗粒较粗的材料可以采用这种模拟方法。

流体计算就有以下特点：1 根据各项同性和各项异性的渗流计算，相应采用两种流体运动定律。

流动中的null材料用来模拟流动范围内的非渗流材料。

2 不同区域可以拥有不同的流动模型（isotropic, anisotropic or null）和模型参数。

3 可以事先指定流体的压力、流量、非渗流区边界条件。

4 流体源可以以电源，也可以以体源的形式插入到材料中，这些源对应于流体的流入或流出，可以随着时间而变化。

5 对于完全饱和流动，可以采用显式和隐式两种算法，但对于非饱和流动则只能采用显示计算。

6 任何力学和温度计算模型都可以与流体模型一起使用，在耦合计算中，可以考虑饱和体的压缩性和热膨胀性。

7.流体与力学计算的耦合通过提供比奥系数来实现。

和不排水温度系数β8．与温度的耦合计算可以通过提供线性热膨胀系数αt（undrained thermal coefficient,可能翻译的不对）来实现。

9.热-流体计算以线性理论为基础，假定材料参数为常数，不考虑对流。

流体与实体的温度保持局部平衡。

非线性行为可以采用FISH语言改变孔隙压力、材料特性来实现。

flac2d基本命令操作

i=21
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Set grav 9.81 Set large Step 1000 Save test.sav
4.9 㒧ᵰᰒ冫
Plot grid ᰒ冫㔥Ḑ Plot bo ᰒ冫䖍⬠ Plot plas ᰒ冫ลᗻऎ Plot sig1 fi ᰒ冫᳔໻Џᑨ࡯V1 Plot sig2 fi ᰒ冫᳔ᇣЏᑨ࡯V2 Plot sdif fi ᰒ冫Џᑨ࡯Ꮒ(V1- V2) Plot str ᰒ冫Џᑨ࡯ⶶ䞣എ Plot xdis fi ᰒ冫Xᮍ৥ԡ鼠 Plot ydis fi ᰒ冫Yᮍ৥ԡ鼠 Plot disp ᰒ冫ԡ鼠ⶶ䞣എ
㲹⢑㳂㬟
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SI Length Density Force Stress Gravity Stiffnes s m kg/m3 N Pa m/sec2 Pa/m m 103kg/m3 kN kPa m/sec2 kPa/m m 106kg/m3 MN MPa m/sec2 MPa/m cm 106g/cm3 Mdynes bar cm/s2 Bar/cm Imperial ft slugs/ft3 Ibf Ibf/ft2 ft/sec2 Ibf/ft3 In snails/in3 Ibf psi in/sec2 Ib/in3
x2,y2
x1,y1
˄4˅ӏᛣᔶ⢊ tab 1 x1,y1, x2,y2, },xn,yn, x1,y1 gen tab 1
(x3,y3) (x2,y2) (x4,y4)
(x1,y1) (x6,y6)
(x5,y5)
4.6 䌟㒭ऩ‫ܗ‬ᴤ᭭ᗻ䋼
mod e (ᔍᗻ) prop d 1800e-6 bu 12.5 sh 5.77 i=1,20 j=1,10 prop d 2400e-6 bu 1250 sh 577 i=1,20 j=11,20 mod m ˄ᔍลᗻMohr-Coulumb‫˅߭ޚ‬ prop d 1800e-6 bu 12.5 sh 5.77 c 0 fri 20 ten 0.015 reg i,j

有限元分析方法之FLAC程序说明1

FLAC程序说明书2004-8-26FLAC(version 2.00)Fast Lagrangian Analysis of Continua目录1.0引论1.1FLAC的技术要求及装机 (3)1.2 绘图机故障分析42.0立即满意－应用FLAC的一个简单指导性示例42.1建造在非线性之中的壕沟43.0基础知识—显式有限差分法8 3.1引论83.2显式／计算循环83.3有限差分格式93.3.1导数的表示93.3.2运动方程式93.4速度／应变增量方程式93.5应力／应变规律103.6确定网点处的不平衡力103.7应力转动修正项11参考文献124.0输入指令4.1定义124.2输入命令124.3设置你自己的默认条件参考文献5.0用FLAC解答的问题5.1引论285.2运行FLAC285.2.1网格的形成及材料特性的定义295.2.2应用边界条件335.2.3应用荷载／变化条件335.2.4数据的打印及绘图335.3特殊问题的考虑365.3.1大应变365.3.2平面应力365.3.3重力365.3.4图形形状365.3.5存入365.4错误处理375.5储存／复原运行37 5.6建议及忠告376.0 FLAC中的结构模拟396.1命令结构396.2定义结构单元的几何条件及其支承介质的联动装置406.3实例应用407.0例题457.1例1无摩擦粘土上的毛石基脚45 7.2例2 粘性摩擦土的边坡稳定47 7.3例 3 端部有剪力的弹性悬臂梁517.4例4弹性，弹塑性及横向各向同性岩石介质中，受初应力作用的圆形隧洞7.4.1弹性岩石介质517.4.2弹塑性岩石介质537.4.3横向各向同性岩石介质55参考文献568.0运行FLAC时值得注意的重点及注意事项578.1初始化各变量578.2改变材料模型578.3运行含现场应力和重力的问题57 附录A本构模型描述59A1引论59A2弹性各向同性模型59A3Mohr－Coulom模型A4空模型A5各向异性弹性60A6多处存在结理的模型61A7应力软化／强化模型61参考文献63附录B利用FLAC时确定平衡条件64 附录C错误及警告信息66附录D FLAC中的界面逻辑68 FLAC快速查阅命令清单70FLAC 2.01版补遗72FLACFast Lagrangian Analysis of Continua(Version 2.00)@1987ITASCA Consulting Group, INC.P.O.Box :14806Minneapolis, MinneSota 55414ITASCA Consulting Group, INC.持有执照的FLAC的条款及规则（Terms and for licensing FLAC）使用FLAC程序之前，你应当仔细阅读以下各条款及规则．把FLAC插入你的计算机，意味着你已承认这些条款及规则．如果你不这个程序是由Ttasca咨询小组有限公司提供的．给记录的数个体起的名称和给支持所起的名称是使用转递用的，但给程序起的名称．达到你的预想效果，并负责安装，使用及从程序中获得结果．许可证（License）在任何一个时间，你只又能在一台计算机使用这个程序．仅仅为了延伸利用，你可以复制备份程序．除了本文件提到外，你不能利用，复制，修改或传送本程序或任何复制大部分或一部分．你不能再执照，出租本程序．有效期限（Term）本许可证终止前一直有效．任何时候，你可以通过程序运用备份拷贝来终止它．如果你不遵守（fail to comply with）本的任何条款或条件，它也会终止．你同意这样的终止，使坏程序连同备份拷贝，以任何方式的修改和／或的各部分．保证书(Warrany)在本代码，在12个月内将免费改正代码中的任何错误，完整的表列输入及输出文件，并错误的书面形式，给出通知．如果经判断，代码有错误，将视情况免费修改或交换拷贝，或偿还．责任界限(Limitation of Liability)概不负责：关于FLAC或任何部分的使用；关于使用而造成的任何损坏或掉失，包括由于使用FLAC而造成的时间，金钱或信誉损失（包括各种修改或改正而造成的）．决不负责因使用FLAC而造成的间接的，错误的，偶然的或随时而发的各种损坏．1.0引论FALC是一种显式有限差分代码（explicit finite difference code），它模拟由岩土或其它材料建造的结构物的性能；这些材料达到屈服极限时，可能经历塑流．这些材料是通过构成一个网格的域或者单元来表示的；这个网格由用户调整，以拟合模拟对象的外形。

flacs 英文使用手册

flacs 英文使用手册
FLAC (Free Lossless Audio Codec) 是一种无损音频压缩格式，可以用于
存储和传输高质量的音频数据。

以下是一份简要的 FLAC 英文使用手册：
1. 什么是 FLAC？
FLAC 是一种免费的无损音频压缩格式，这意味着压缩过程中不会丢失任何
原始音频数据。

与有损压缩格式（如 MP3）相比，FLAC 可以提供更高的音频质量和更小的文件大小。

2. 如何创建 FLAC 文件？
可以使用各种软件将音频文件转换为 FLAC 格式。

常见的音频编辑软件如Audacity、Winamp 等都支持 FLAC 格式。

只需将音频文件导入软件中，
选择 FLAC 作为输出格式，然后进行压缩即可。

3. 如何播放 FLAC 文件？
大多数现代音频播放器都支持FLAC 格式，包括Windows Media Player、VLC Media Player、foobar2000 等。

只需将 FLAC 文件添加到播放器中，即可开始播放。

4. FLAC 文件的优点和缺点？
优点：无损压缩，可以完全还原原始音频数据；高音频质量，适合存储高质量的音乐。

缺点：文件大小相对较大，与有损压缩格式相比不具有优势；不是所有设备都支持 FLAC 格式。

5. 如何与其他音频格式转换？
可以使用各种软件将 FLAC 文件转换为其他音频格式，如 MP3、WAV 等。

常见的音频编辑软件都支持多种输出格式，只需选择所需的格式进行转换即可。

以上是一份简要的 FLAC 使用手册，希望对您有所帮助。

flac3D 用户手册(中文)

果没有找到，它就会到安装目录下寻找。它的作用是存放用户设定的程序初始化
模式的命令。以便每次打开软件都载入用户的初始设置。
如果“FLAC3D.INI”文件不存在，软件继续运行而不会提示出错信息，注意
一点：一些存储在“FLAC3D.INI”里的命令，如果并不是设置初始化的命令，有
可能导致错误的信息。
2.1.8 运行FLAC3D
Flac3d命令驱动模式包括两种方式：交互模式（在命令窗口中输入命令行）；
命令流模式（将命令行保存在数据文件中，通过读入该文件执行相关命令）。如
果输入的命令存在错误，那么窗口中将会出现错误提示。命令流文件一般通过文
本编辑器创建和修改（见2.14节），虽然命令流文件可以定义为任何文件名，但
是最好设定其扩展名为“.dat”，以防止和flac3d其它类型的文件相混淆。
“Plot clipboard”命令可以将显示的图形，存放到 WINDOWS 剪贴板上（没有任何文件生成）。该图形接着就可以以加强型图元文件格式被粘贴到其它兼容该格式的 WINDOWS 应用程序中去。
“Set plot metafile”命令可以将图形以加强型图元格式存盘，以便作为计算的参考或日后插入到文档中去。
.5.
FLAC3D3.0 版本中文手册
翻译：一米
2.2 一个简单的计算教程——常用命令的使用
这一部分主要是为那些刚接触FLAC3D，跃跃欲试的新用户准备的。在这一部分，将通过一个简单的例子来帮助用户学习一些求解问题的基本知识。
例题的主要问题描述如下：在一块土体中一次性开挖一个2m×4m×4m的沟渠，并对沟渠周围土体的变形作监测和分析。为了给用户提供方便，在安装目录中“\Tutorial\Beginner”文件夹下的“TUT.DAT”数据文件里包含了本例题使用的所有命令。

flac常用命令

flac3‎d常用命令‎1、最先‎需要掌握的‎命令有哪些‎？答：需‎要掌握 g‎e n, i‎n i, a‎p p, p‎l o, s‎o lve ‎等建模、初‎始条件、边‎界条件、后‎处理和求‎解的命令。

‎2、怎样‎输出模型的‎后处理图？‎答：Fi‎l e/Pr‎i nt t‎y pe/J‎p g fi‎l e，然后‎选择 Fi‎l e/Pr‎i nt，将‎保存格式选‎择为 jp‎e文件。

‎3、怎样‎调用一个文‎件？答：‎F ile/‎c all ‎或者 ca‎l l 命令‎4、如何‎施加面力？‎答：ap‎p nst‎r ess ‎5、如何调‎整视图的大‎小、角度？‎答：综合‎使用 x,‎y, z‎, m, ‎S hift‎键，配合‎使用Ct‎r l+R，‎C trl+‎Z等快捷‎键。

6、‎如何进行边‎界约束？‎答：fix‎x ra‎n（约束‎的是速度，‎在初始情况‎下约束等效‎于位移约束‎）。

7‎、如何知道‎每个单元的‎ID？‎答：用鼠标‎双击单元的‎表面，可以‎知道单元的‎ID 和‎坐标。

8‎、如何进行‎切片？答‎：plo ‎s et p‎l ane ‎o ri (‎点坐标) ‎n orm ‎(法向矢量‎) plo‎con ‎s z pl‎a ne (‎显示 z ‎方向应力的‎切片) 9‎、如何保存‎计算结果？‎答：sa‎v e +文‎件名 10‎、如何调用‎已保存的结‎果？答：‎r est ‎+文件名；‎或者 Fi‎l e / ‎R esto‎r 11、‎如何暂停计‎算？答：‎E sc 1‎2、如何在‎程序中进行‎暂停，并可‎恢复计算？‎答：在命‎令中加入‎p ause‎命令，用‎cont‎i nue ‎进行继续。

‎在我们分‎步求解中想‎得到某一个‎过程中的结‎果，不用等‎到全求完，‎还可以在‎分布求解错‎误的时候就‎进行改正，‎而不是等到‎结果出来。

‎13、如‎何跳过某个‎计算步？‎答：在计算‎中按空格键‎跳过本次计‎算，自动进‎入下一步‎14、Fi‎s h 是什‎么东西？F‎i sh 是‎否一定要学‎？答：是‎FLAC‎3D 的内‎置语言，可‎以用来进行‎参数化模型‎、完成命令‎本身不能‎进行的功能‎。

FLAC讲解

j=21
i=21
（3）赋单元内应力（单元）
ini sxx -10 i=1,20 j=1,20 ini syy -5 var 0 4 i=1,21 j=1,21
j=21
i=21
Set grav 9.81 Set large Step 1000 Save test.sav
Plot grid 显示网格 Plot bo 显示边界 Plot plas 显示塑性区 Plot sig1 fi 显示最大主应力1 Plot sig2 fi 显示最小主应力2 Plot sdif fi 显示主应力差(1- 2) Plot str 显示主应力矢量场 Plot xdis fi 显示X方向位移 Plot ydis fi 显示Y方向位移 Plot disp 显示位移矢量场
mod ulus )
（1）固定边界（结点）
Fix x i=1, j=1,21 Fix y i=1,21 j=1
Fix x
i=1 Fix y
j=1
（2）施加边界力 (结点)
apply yf -10 i=1,21 j=21 或 apply syy -10 i=1,21 j=21 apply xf -5 i=21, j=1,21 或 apply sxx -5 i=21, j=1,21
（1）量纲统一
SI Imperial
Length
Density Force Stress
m
kg/m3 N Pa
m
103kg/m3 kN kPa
m
106kg/m3 MN MPa
cm
106g/cm3 Mdynes bar
ft
slugs/ft3 Ibf Ibf/ft2
In
snails/in3 Ibf psi

flac使用说明

FLAC程序简介FLAC是FAST LAGRANGIAN ANALYSIS OF CONTINUA的缩写,是由美国明尼苏达ITASCA软件公司开发的通用程序。

该程序在中国大陆以外已有较多的用户，应用很普遍。

该程序刚引进国内，目前国内尚在推广应用。

FLAC程序的基本原理和算法与离散元法相近，是由P.A．Cundall提出的。

它与离散元法的区别在于它应用了节点位移连续的条件，可用于连续介质的大变形分析。

由于它不必形成像有限元法中那样的整体刚度矩阵，因此可以在内存较小的微机上计算较大规模的题目。

例如对于4M内存的微机可运行大约15000个单元的题目。

FIAC程序可以模拟弹性模型材料，摩尔—库仑模型材料，横观各向同性模型的层状材料，具有软弱夹层的节理材料等六种。

它还可以模拟地应力场的生成、洞室或边坡开挖、回填混凝土、锚杆锚索安设、地下渗流等。

尤其是对锚杆的设置非常方便，可以在任何指定位置设置锚杆而不考虑网格的划分和结点的分布。

FLAC程序的另一特点是，它具有强大的前后处理功能。

网格自动生成，界面美观。

用户可以使用各种命令修正网格以适应各种复杂边界，计算结果均可以有图形输出，并可着色。

这包括各期的主应力分布向量、σx、σy、τxy分布等值线，位移向量，Ux、Uy等值线，塑性区范围，锚杆受力等等。

使用方便快速。

FLAC可以按两种方式运行，既可以通过数据／命令文件运行，又可通过人机对话方式运行。

用户可以在FIAC运行中的任何时候中断它，修改数据后继续运行。

FLAC2.25使用说明书FLAC 的输入和一般的数值模拟的程序不一样, 它可以用交互的方式从键盘输入各个命令, 也可以写成命令文件, 类似于批处理, 由文件来驱动。

FLAC 命令大小写一样。

所有的命令可以附带若干个关键词和有关的数值。

在下面的命令解释中, 只有大写的字母起作用, 小写的字母写不写、写多少个都没有关系。

i,j,m 和n 开始的变量要求整型数, 否则要求实型数。

Flac3D中文手册

Flac3D中文手册Flac3D 中文手册FLAC3D的计算模式中是否需要做孔压分析取决于是否采用config fluid命令。

1 无渗流模式（不使用config fluid）即使不使用命令config fluid，仍然可以在节点上施加孔压。

这种模式下，孔压将保持为常量。

如果采用塑性本构模型的话，材料的破坏将由有效应力状态来控制。

节点上的孔压分布可由initial pp命令或water table命令来设定。

如果采用water table命令，由程序自动计算水位线以下的静水孔压分布。

此时，必须施加流体密度（water density）和重力（set gravity）。

流体密度值和水位位置可以用命令print water显示。

如果水位线是由face关键字来定义的，则可用命令plot water命令显示水位。

这两种情况，单元的孔压都由节点孔压值平均求出，并在本构模型计算中用作有效应力。

这种计算模式下，体积力中不反映流体的出现：用户必须根据水位线以上或以下相应地指定干密度和湿密度。

使用命令print gp pp和priint zone pp可分别得到节点或单元孔压。

plot contour pp命令可绘出节点孔压云图。

2 渗流模式（使用config fluid）如果使用命令config fluid，则可进行瞬时渗流分析，孔压改变和潜水面的改变都可能出现。

在config fluid模式下，有效应力计算（静态孔压分布）和非排水计算均被执行。

除此之外，还可进行全耦合分析，这种情况下，孔压改变将使固体产生变形，同时体积应变反过来影响孔压的变化。

如果采用渗流模式，单元孔压仍由节点孔压平均求出。

但这种模式，用户只能指定干密度（不论是水位以上还是以下），因为FLAC3D 将流体的影响考虑到了体积力的计算中。

采用渗流模式时，渗流模型必须施加到单元上，使用命令model fl_isotropic模拟各向同性渗流，model fl_anisotropic模拟各向异性渗流，model fl_null模拟非渗透物质。

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FLAC 输入命令FLAC 的输入和一般的数值模拟的程序不一样, 它可以用交互的方式从键盘输入各个命令, 也可以写成命令文件, 类似于批处理, 由文件来驱动。

FLAC 命令大小写一样。

所有的命令可以附带若干个关键词和有关的数值。

在下面的命令解释中, 只有大写的字母起作用, 小写的字母写不写、写多少个都没有崐关系。

i,j,m 和 n 开始的变量要求整型数, 否则要求实型数。

•实型数的小数点可崐以忽略, 但是整型数不能带小数点。

数值间可以用空格隔开, 空格的数目不限,•也可以用下面的分隔符隔开:( ), / =< > 表示可选的参数, 输入时括号不用输入;... 表示可以有任意个参数。

由 * 号开始到行末为注释, FLAC 在执行时不理会。

下面的 FLAC 命令按字母排列。

Apply 关键词 = 数值 <关键词 = 数值 ...> <范围>可以有下面的关键词:Pressure 压力XForce X-方向的力YForce Y-方向的力ATtach 该命令可以将一条线上的结点和另一条线上的结点互相接合在一起, 用以形成复杂的网格形状。

Call 文件名写成的命令文件可以用 Call 命令来调用, 命令文件的最后一行必须是RETURN, 以返回到交互方式。

命令文件中不能有 CALL 命令本身。

Config 关键词FLAC 用以解平面应变问题, •但经过配置命令也可以用于解平面应力问题或轴对称问题。

需要时应在形成网格之前发。

关键词有:P_STR 平面应力问题AX 轴对称问题CYC n该命令同 STEP, 为执行 n 个时步的循环运算。

Fix X <Mark> <范围>YX Y用此命令可以使 <范围> 内结点的 x- 或 y- 方向的速度保持不变。

<范围> 的格式可以是 I = i1,i2, J = j1,j2; i 和 j •何者先输入没有关系。

如果要求位移固定, 则必须将速度初始化为零 (开始时速度的缺省值为零)。

FIX 和 INI XV, YV •可以联合使用以提供一个刚性移动的边界条件。

如果有 MARK 的关键词, 则只有在此范围内被标记的结点将被固定。

FRee X <Mark> <范围>YX Y该命令与 FIX 命令相反, 用于放松对结点的约束。

GEn x1,y1 x2,y2 x3,y3 x4,y4 <Ratio ri rj> <range><Same> <Same> <Same> <Same>用于在全域或局域中产生网格。

(x1,y1)的点放在左下侧, (x2,y2)、(x3,y3) 和 (x4,y4) 为顺时针排列。

如果点和前一个 GEn 命令中的相同则用 SAME 来代替。

如果网格不是均匀排列, 则用关键词 RATIO,•在 I 和 J 方向的比例系数分别为 ri 和 rj.GEn Circle xc,yc radArc xc,yc xb,yb thetaLine x1,y1 x2,y2该命令产生园、弧或直线。

ARC 弧的圆心为 (xc,yc), 起始点为 (xb,yb), 逆时针的角为theta 度CIRCLE 园的中心为 (xc,yc), 半径为 radLINE 直线的两端为 (x1,y1) 和 (x2,y2).用 ARC 等关键词所形成的边界系被标记 (参见命令 MARK 和 UNMARK)过, 标记结点所围住的区域在以后用命令 INITAL, MODEL 和 PROPERTY时可以用关键词 REGION 来说明。

Gen ADJust用此命令来微调网格, 使之离散平滑。

该命令可以连续使用以增进平滑效果的。

Grid icol jrow此命令用以产生数目为 icol 列和 jrow 行的网格。

对于 640k 内存的FLAC 版本, 如用摩尔-库仑的本构模型约可分两千个单元。

Help 帮助命令, 可在屏幕上显示命令表。

His <Nstep=n> <关键词 . . . I=i1 J=j1>每隔 NSTEP 时步, 记录一下关键词所示项目在 i1 和 ji •结点或单元的数值。

NSTEP 的缺省值为 10. 用户应记住所要求 His (历史)•的顺序, 因以后在打印或绘图时要用。

历史值在 FLAC 停止运行时删除, 因此如果要保留的话, 要用到命令 HIS WRITE N (见下面)。

可以用的关键词有:Ang 单元 i,j 内的最小主应力和 X-轴所形成的夹角PP 单元 i,j 内的孔隙压力SIG1 单元 i,j 的最大主应力SIG2 单元 i,j 的最小主应力SXX 单元 i,j 的 xx-应力SYY 单元 i,j 的 yy-应力SXY 单元 i,j 的 xy-应力X 结点 i,j 的 x-坐标Y 结点 i,j 的 y-坐标XDis 结点 i,j 的 x-位移YDis 结点 i,j 的 y-位移Unbal 最大不平衡力XVel 结点 i,j 的 x-速度YVel 结点 i,j 的 y-速度XXA 单元 i,j 三角形 a 的 xx-应力XYA 单元 i,j 三角形 a 的 xy-应力YYA 单元 i,j 三角形 a 的 yy-应力XXB 单元 i,j 三角形 b 的 xx-应力XYB 单元 i,j 三角形 b 的 xy-应力YYB 单元 i,j 三角形 b 的 yy-应力XXC 单元 i,j 三角形 c 的 xx-应力XYC 单元 i,j 三角形 c 的 xy-应力YYC 单元 i,j 三角形 c 的 yy-应力XXD 单元 i,j 三角形 d 的 xx-应力XYD 单元 i,j 三角形 d 的 xy-应力YYD 单元 i,j 三角形 d 的 yy-应力His 关键词关键词可以是:Dump nhis 将第 nhis 的历史写屏;Write nhis 将第 nhis 的历史写在文件 FLAC.HIS 上, •该文件可在 FLAC 结束后打印出来。

连续执行 HIS WRITE 命令可将结果顺序写在 FLAC.HIS 上, •但是首次执行此命令会将以前盘上所存的同名文件冲掉;Reset 所有的历史都清除掉。

Initial 关键词 = 值 <. . . > <范围>某些结点值可以给初值:PP 空隙压力X x-坐标Y y-坐标SXX xx-应力SYY yy-应力SXY xy-应力XDisp x-位移YDisp y-位移XVel X-速度YVel y-速度还有几个可选用的关键词以协助实现 INITIAL 命令:Mark 只有标记的结点值将被初始化Region i j为标记结点所围住的区域将被初始化。

i,j 为标记区域中的任一个单元Var xv, yv 在一定范围内的参数的变差值, xv 和 yv 为 x-方向和 y-•方向的变差值。

范围可以有形式 I=i1,j1 J=j1,j2, 其中 i 和 j 的先后次序无关。

INTerface n 关键词 <i1,j1> <i2,j2>n 关键词 = 值INTERFACE 为交界面命令。

网格的一部分可以和网格的另一部分通过交界面而相互作用。

界面的性质由其刚度, 粘结力和摩擦力来表征。

用于本命令的关键词有:Aside i1,j1 <i2,j2 i3,j3 ...>Bdide i1,j1 <i2,j2 i3,j3 ...>Cohesion 粘结力值Friction 摩擦力值GluedKN 法向刚度值KS 切向刚度值TBond 抗拉强度Unglued胶结命令 GLUE 将使交界面的上下两部分胶结在一起, 使之不能滑动和分离, 命令 UNGLUE 则为命令 GLUE 之逆。

MArk <范围>在给定范围内的结点将被标记。

计算的进行与结点的标记与否无关, 但标记的结点可以限定一个区域作为命令 INITIAL, PROP 和 MODEL 的作用域。

命令 GEN 将自动对结点进行标记。

<范围>的形式可以是 I=•i1, i2, J=j1,j2, i 和 j 的顺序无关。

Model 关键词 <REGION=i,j> <范围>该命令对于给定的区域或范围赋予有关的本构模型。

关键词有:ANisotropic 横观各向同性弹性模型Elastic 弹性, 各同性本构模型Mohr-Coulomb 摩尔-库伦塑性模型Mull 零模型, 用于开挖掉的单元SS 应变软化Ubiquitous 彻体节理模型NEW 该命令可以不用退出 FLAC 重新开始一个新问题。

Plot 关键词 <开关 <= v>...> <关键词 ...>用缺省值。

可以在一行上连写几个关键词以在一个图上画出几个变量。

在绘图前先要用 MODEL 命令赋予网格以一定的本构模型。

•关键词及其意义为:BEam 画出结构单元的几何形状Boundary 画出网格的内外边界Cable 画出锚束的几何形状Disp 位移矢量E_p 塑性应变的轮廓线 (只限于应变软化材料)Grid 画出画出纪录在第 nhis 个历史上的变量值PP 孔隙压力的等值线RF 以矢量形式画出的固定结点的反力STAte 画出单元中心当前的屈服状态STress 主应力矢量SXX xx-应力的等值线 (全应力)SYY yy-应力的等值线 (全应力)SXY xy-应力的等值线Velocity 以箭头画出的速度矢量WAter 水位线XDisp x-位移的等值线YDisp y-位移的等值线XVel x-速度YVel y-速度所谓开关其本身也是关键词, 用于设置图形的的某些特征, 有:color 如红为 Red, 绿为 GREen, 黄为 Yellow 等。

Interval = c将等值线的间距置为 c.• •在 •PLOT •命令前发扫描线命令SCLIN 可以画出等值线的值。

Max = v 在画矢量时, 置箭头的最大长度为 v.Noh 不画标题Zero 不画零值线如果要放大或缩小图形, 可以在 PLOT 命令前用 WINDOW 命令来设置窗口的大小。

Print 关键词 <关键词>... <Region=i,j> <范围>和绘图命令 PLOT 一样, 结点变量的值只有在给定的材料模型和性质后才可以打印出来。

关键词有:Apply 打印出所施加力或压力的大小和范围Fix 打印出固定 x 或 y 的结点Limits 对 SOLVE 命令的限制值MArk 打印出标记结点MEm 占用的内存STruct 打印出结构单元上有关结点的力, 力矩和位移Interface 打印出交界面的数据, 包括结点力和单位法向矢量主要的网格关键词Bulk 体积模量COhesion 粘结力Den 质量密度Dilation 剪胀角E_p 全塑性应变 (应变软化模型)Friction 摩擦系数SHear 剪切模量X X-坐标Y Y-坐标PP 孔隙压力JFric 节理摩擦力JCoh 节理粘结力JAngle 节理角度NUYx y-x 泊松比NUZx z-x 泊松比SIG1 最大主应力SIG2 最小主应力SXX XX-应力SYY YY-应力SXY XY-应力Theta 最小主应力与 x-轴的夹角XDis X-位移YDis Y-位移XMod X-模量YMod Y-模量XVel X-速度YVel Y-速度ASXX XX-应力 (三角形 A)BSXX XX-应力 (三角形 B)CSXX XX-应力 (三角形 C)DSXX XX-应力 (三角形 D)ASYY YY-应力 (三角形 A)BSYY YY-应力 (三角形 B)CSYY YY-应力 (三角形 C)DSYY YY-应力 (三角形 D)ASXY XY-应力 (三角形 A)BSXY XY-应力 (三角形 B)CSXY XY-应力 (三角形 C)DSXY XY-应力 (三角形 D)State 塑性状态0 弹性1 正在屈服中2 曾经屈服, 现为弹性3 已超过单轴抗张力4 屈服并超过单轴抗张力5 已经超过抗张力6 彻体节理正在屈服7 彻体节理过去屈服过, 现为弹性状态Tables 打印所存贮的表格XReaction X-反力YReaction Y-反力PROp 关键词 =值 < . . . > <范围>本命令为 MODEL 命令赋予材料的性质。