flac3d5.0结构单元教程ppt课件
FLAC3D岩土软件-本构模型ppt课件
弹性本构模型
零模型 — 所有的应力均为零: 模拟挖空区 弹性模型 — 各向同性，线性 各项异性 — 弹性，假定单元为横观各项异性
ቤተ መጻሕፍቲ ባይዱ
g
b
y b
f
x
-b 面为对称面. , b 轴与 x, y轴呈任意角度
CHINA UNIVERSITY OF MINING AND TECHNOLOGY
塑性本构模型
德鲁克-布拉格; 摩尔-库伦; 单一节理; 应变硬化-软化; 双屈服; 修正剑桥粘土; 霍克-布朗
CHINA UNIVERSITY OF MINING AND TECHNOLOGY
CHINA UNIVERSITY OF MINING AND TECHNOLOGY
CHINA UNIVERSITY OF MINING AND TECHNOLOGY
CHINA UNIVERSITY OF MINING AND TECHNOLOGY
CHINA UNIVERSITY OF MINING AND TECHNOLOGY
CHINA UNIVERSITY OF MINING AND TECHNOLOGY
CHINA UNIVERSITY OF MINING AND TECHNOLOGY
水力回填材料
位于粘土中的岩土工程 位于岩石中的岩土工程
CHINA UNIVERSITY OF MINING AND TECHNOLOGY
CHINA UNIVERSITY OF MINING AND TECHNOLOGY
CHINA UNIVERSITY OF MINING AND TECHNOLOGY
本构模型的选择
Model <关键字> range
model mohr
(完整版)FLAC3D5.00培训教程
将FLAC3D文件打包 和解包！！
1.1.4 the status bar
状态栏
面板控制的快捷键
每个面板都对应着与面板操作相关的快捷按 钮！
快捷键
重新加载上一条或下一条命令！！！
可以单独保存list文件！！！
项目管理 Project .f3prj格式
➢ 将 datafile、plot、savefile 统一起来，构成整 个项目。
鼠标放在模型上 就会显示相关信 息。
缩小
放大恢复
Extrusion Pane
An extruded mesh generated using the extrusion capability in FLAC3D
The Extrusion pane is used to create one or more extrusion sets. It is accessed (if not already visible) by selecting it from the Panes menu. An extrusion set is a 2D shape (drawn) that is linearly extended (extruded) to a third dimension. Once it has been defined in this way, an extrusion set may be used to generate a 3D mesh for use in FLAC3D. Though there is only ever one instance of the Extrusion pane in FLAC3D, multiple extrusion sets may be loaded into it at the same time. The pane provides two distinct views of the extrusion set: the construction view, where the 2D shape is drawn, and the extrusion view, where the extent of the extrusion is specified. These are introduced in the topic Views.
-_FLAC3D5.0_InitialStress
• size 6 6 10
• •
mproodeblulelkas10e10常sh规e 法10e10
• ini den 2500
• ini sxx -1e9 grad 0 0 1.1111111e7 range x -.1 .1
• ini sxx -1e9 grad 0 0 6.6666666e6 range x 59.9 60.1
FLAC3D 5.0培训教程（武汉）
工程师 李振 2014.3.27-3.28 Itasca(武汉)安排
2014.3.27~ 2014.3.28
1. FLAC3D V5.0界面操作 2. FLAC3D基本操作方法vs应用流程；
initial stress 3. FLAC3D内置Fish语言的应用； 4. FLAC3D结构单元vs接触单元； 5. FLAC3D渗流模块 6. 其他
精品课件
几种形成初始应力的方法
1. 弹性求解的方法 2. 更改强度参数的弹塑性求解 3. 分阶段弹塑性求解(mohr—solve elas) 4. 存在静水压力的初始应力（水下构筑物） 5. 深埋地应力场
精品课件
1、弹性求解的方法
精品课件
2、更改强度参数的弹塑性求解
精品课件
2、更改强度参数的弹塑性求解
• ini syy -1e9 grad 0 0 8.3333333e6 range y -.1 .1
• ini syy -1e9 grad 0 0 8.3333333e6 range y 59.9 60.1精品课件
精品课件
深埋工程地应力场
精品课件
• size 6 6 10
• model elas
• pro深bu埋lk工10程e10地sh应e 力10e场10 —SB法
FLACD基础知识PPT课件
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9、数据记录
• hist gp xdisp -0.1 30 1.55 • hist gp xdisp 4.62 30 1.55 • hist gp zdisp 2.26 15 3.2 • hist gp zdisp 2.26 15 -0.1 ; • 显示： • plot hist 1 • plot hist 2
gen zone cyl p0 0 0 0 p1 5 0 0 p2 0 3 0 p3 0 0 5 size 5 3 6 group 2
圆柱形
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gen zone radb p0 0 0 0 p1 5 0 0 p2 0 3 0 p3 0 0 5 p8 3 0 0 p9 0 2 0 p10 0 0 2 size 5 3 6 8 group 3
位移边界和应力边界
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应力边界
• apply szz=-1e5 sxz=-.5e5 range z -.1 .1
z
σzz
σxz
x
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应力梯度的施加
• apply sxx -10e5 gradient 0 0 1e5 range z 100 0
z
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σxx
圆柱形 隧道
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gen zone cshell p0 0 0 0 p1 5 0 0 p2 0 3 0 p3 0 0 5 p8 3 0 0 p9 0 0 3 p10 3 3 0 p11 0 3 3 size 3 5 10 4 group 1
圆柱壳体
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gen zone cylint p0 0 0 0 p1 5 0 0 p2 0 5 0 p3 0 0 5 p8 3 3 0 p9 0 0 3 p10 3 5 0 p11 0 5 3 p12 5 3 0 p13 5 0 3 size 3 5 10 4 group 1
flac三D5.0结构单元教程专题培训课件
2、结构单元的建模方法—壳型结构单 元
通过附着在实体网格表面来生成shell单元。
因此在建立线型结构单元时，要特别注意nseg变量的大小。nseg太 小则会导致计算不精确，而太大就会违反结构单元建模的基本原则。
3、结构单元的参数取值
梁单元
锚索单元
• emod——弹性模量，E
• emod——弹性模量， E
• nu——泊松比，ν
• xcarea——横截面积，A
• xcarea——横截面积，A
起始点坐标并给定分段数目的方法； 建立梁单元，并显示 单元坐标系！
2、结构单元的建模方法—线型结构单 元
ID号相同，共用Node，ID不同，各个ID对应的结构单元有各自独立的node。除非设 置联系，否则即使节点位于同一位置也不会传递力。
结示的命令文件另存出来，以备下次使用。（最适用于 几何模型相同，参数不同的，不同工况分析的比较）
StructuralElement
FLAC3D结构单元
1. 结构单元的类型 2. 结构单元的建模方法 3. 结构单元的参数取值 4. 结构单元实例分析 5. 关于link
1、结构单元的类型
FLAC3D中包含六种形式的结构单元，可以分成两类：
线型结构单元：
• 梁单元(beam) • 锚索单元(cable) • 桩单元(pile)
• slide——大变形滑动标志
• pmoment——塑性矩，Mp • thexp——热膨胀系数，αt • ydirection——矢量Y
2024版FLAC3D5.0培训
06
总结与展望
本次培训总结
培训内容丰富
涵盖了FLAC3D5.0的基本原理、 建模方法、分析步骤、后处理等 多个方面，使学员能够全面了解
并掌握该软件的使用。
培训方式多样
采用了理论讲解、案例分析、实 践操作等多种培训方式，使学员 在理论学习的基础上，通过实践 操作加深了对软件的理解和掌握。
培训效果显著
程中的应力、变形和稳定性。
02
支护结构设计与优化
根据隧道开挖模拟结果，设计合理的支护结构，如锚杆、喷射混凝土等，
并利用FLAC3D5.0对支护结构进行优化。
03
隧道施工风险评估
基于FLAC3D5.0的模拟结果，对隧道施工过程中可能出现的风险进行评
估，提出相应的应对措施。
基坑开挖与支护设计
基坑开挖过程模拟 利用FLAC3D5.0建立基坑三维模型，模拟基坑的开挖过程， 分析开挖过程中的应力、变形和稳定性。
高效建模技巧
利用对称性简化模型
对于具有对称性的结构，可以只建立一半或四分之一的模型，通过设置对称边界条件来模拟 整个结构，从而大大提高建模效率。
使用模板快速创建复杂模型
FLAC3D5.0提供了丰富的模板库，用户可以直接调用模板来创建复杂的模型，避免了繁琐的 建模过程。
批量修改模型参数
通过编写脚本或使用内置工具，可以实现对模型参数的批量修改，提高建模效率。
边界条件设置方法
根据实际问题的要求，设置合理的边界条件。对于 固定边界，可将其节点位移约束为零；对于自由边 界，可不施加任何约束。同时，还需考虑边界条件 的对称性和周期性等因素。
网格密度控制
根据计算精度和计算效率的要求，合理控制网格的 密度。在关键区域和应力集中区域可采用较密的网 格，以提高计算精度。
(2024年)FLAC3D5.0培训教程
精度和计算效率的需求。
2024/3/26
13
接触面处理及摩擦模拟
2024/3/26
接触面定义
01
支持定义不同材料之间的接触面，包括摩擦系数、刚度等参数
设置。
接触面行为模拟
02
能够模拟接触面的滑动、张开和闭合等行为，以及接触面间的
传热和传质过程。
动画展示技巧 在制作动画时，可采用一些技巧来提高动画的展示效果， 如使用透明度渐变来突出关键区域的变化、使用色彩对比 来区分不同物理量的分布情况等。
结果数据对比 在动画制作中，可将不同方案或不同时间步的计算结果进 行对比展示，以便更直观地评估不同方案的效果或观察模 型的动态响应过程。
25
06
总结与展望
21
05
数据可视化与后处理
2024/3/26
22
结果数据输出格式
文本文件输出
可将模型计算结果以文本文件形式输出，方便用户进行自定义处理 和分析。
Excel文件输出
可将模型计算结果直接导出到Excel文件中，便于用户进行数据整理、 分析和可视化。
图像文件输出
可将模型计算结果以图像形式输出，如等值线图、云图等，方便用户 进行直观分析和展示。
施方法
学习在FLAC3D中施加边界条件和 荷载的方法，确保模拟过程的真实 性。
11
03
高级功能与技巧
2024/3/26
12
复杂模型处理技术
复杂地形建模
利用地形数据生成三维地形模型， 包括不规则地形、断层、节理等。
复杂结构建模
支持多种结构单元，如梁、板、 壳等，实现复杂结构的精细化建
结构单元和接触面PPT教案
The shells can then be repositioned if ecessary by using the SEL node init command
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2、结构单元的建模方法—注意事项
➢ FLAC3D是岩土工程的专业软件，因此一般很少用来做专门的结 构分析。在涉及到结构单元的问题中，往往都要考虑结构与周围 的实体单元的相互作用。在结构单元的建模时要特别注意一个基 本原则：一个zone至多包含一个structure node!
3、结构单元的参数取值
某些结构单元参数的取值要视具体情况 而定，根据经验且必要时调整参数通过 试算来确定。
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4、结构单元实例分析
4.1、简支梁（beam单元）承受 两个相等集中载荷
4.2、简支梁（shell单元）承受 两个相等集中载荷
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4.1、简支梁（beam单元）承受两个相等集中 载荷
Simple Beam – Two Equal Concentrated Loads
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4.1、简支梁（beam单元）承受两个相等集中载荷
A simply supported beam is loaded by two equal concentrated loads, symmetrically placed as shown in Figure 1.9. The shear and moment diagrams for this configuration are also shown in the figure.The shear force magnitude,V, is equal to the applied concentrated load,P. The maximum moment,Mmax, occurs between the two loads and is equal to Pa. The maximum deflection of the beam,max, occurs at the center and is given by AISC (1980, p. 2-116) as
Flac 3D 5.0教程
第二章完成第一个简单分析计算样例by typing the commands from the keyboard, pressing<Enter>at the end of each command line, and seeing the results directly.newgen zone brick size 6 8 8（This command will create an initial mesh that is six zones in the x-direction, eight zones in the y-direction and eight zones in the z-direction. For our model, the z-axis is oriented in the verticaldirection.）Plot（the Plot Base/0>prompt will appear. As long as this prompt appears, any subsequentcommands will be associated with the PLOT command. The plot view is identified as Base/0,which is the default view.）create Trenchadd surface yellowadd axes blackshowNow, give the zones a material model and properties. For this example, we use the Mohr-Coulombelastic-plastic model. Go back to the Flac3D>prompt in the command window andtype in thefollowing command:modelmohrThis will specify the Mohr-Coulomb model. Every zone in the grid could conceivably have adifferent material model and property. However, by not specifying a range of zonesafter the MODEL command, FLAC3D assumes that all zones are to be Mohr-Coulomb material.prop bulk = 1e8 shear = 0.3e8 fric = 35propcoh = 1e10 tens = 1e10You see that very high cohesion and tensile strength values are given. These areonlyinitial values that are used during the development of gravitational stresses within the body.In effect, we are forcing the body to behave elastically during the development of theinitial insitustress state.* This prevents any plastic yield during the initial loading phase of theanalysis.For this problem, loading is due to gravity. To apply gravity, use the commands setgrav 0, 0, -9.81ini dens = 1000In order to develop a gravitational body force, themass density must also be initialized. The INI command is used to initialize the mass density to1000 kg/m3 for all zones in the model.Next, the boundary conditions for the problem are set. At the Flac3D>prompt, type fix x range x -0.1 0.1fix x range x 5.9 6.1fix y range y -0.1 0.1fix y range y 7.9 8.1fix z range z -0.1 0.1With these commands, roller boundaries are placed on five sides of the model. The boundaries are “fixed” only in the specified direction (i.e., no displacement or velocity is allowed). The FIX commands perform the following functions.1. The gridpoints along the boundary planes at x = 0 and x = 6 are fixed in the x-direction. These two planes fall within the coordinate ranges specified by the range keywords for the first two FIX commands.2. The gridpoints along the boundary planes at y = 0 and y = 8 are fixed in the y-direction. These planes fall within the ranges specified for the third and fourth FIX commands.3. The gridpoints along the bottom boundary (z = 0) are fixed in the z-direction. This plane falls within the range for the fifth FIX command.We wish to monitor the change in the values of selected variables in the model during the calculational stepping. A HISTORY command can assist in helping us determinewhether a stable equilibrium solution or unstable collapse is occurring. We type the following commands:hist n = 5histunbalhistgpzdisp 4,4,8We choose to monitor the change in variables every five calculation steps. It is always a good idea to monitor the maximum unbalanced force in a model. If the unbalanced force approaches a very small value and displacement histories become constant, this indicates that an equilibrium state is reached.To allow gravitational stresses to develop within the body, we timestep the simulation to equilibrium.Here the SOLVE command is used to detect equilibrium automatically.setmech force=50solveWhen the unbalanced force falls below the limiting value (a limiting force of 50 N is specified with the SET command), the run will stop.* The plots are updated, since they are still visible on the screen. Shutting down the plots will cause the model to cycle faster.plothist 1hist 2The unbalanced force history approaches zero, andthe displacement history becomes constant; both are indicators that an equilibriumstate has beenreached.Note that each history is numbered sequentially from 1 as it is entered via the HIST command. Return to the Flac3D> prompt and typeprinthistfor a listing of the histories and their corresponding numbers.Plotcreat trenchadd contour dispadd axes blackshowclearaddbcontourszzadd axesplot create GravVplot set plane dip=90 dd=0 origin=3,4,0plot set rot 15 0 20plot set center 2.5 4.2 4.0plot add bound behindplot add bcontszz planeplot add axesplot showThis sequence will create a view, which we have called GravV, and make it the current view. We then set a plane for that view oriented at a dip angle of 90◦ (from the xy-plane, assuming that negative-z is “down”), a dip direction of 0◦(measured clockwise from the positive y-axis in the xy-plane) and with one point on the plane at (x = 3, y = 4, z = 0). We add a wire-frame boundary plotted behind the plane and a block contour plot of the vertical stress component, σzz, on the plane. Finally, the model axes are added. The block contour plot, as opposed to an interpolated contour plot, displays the value of the stress calculated at each zone centroid. The color of each zone corresponds directly to the zone-based stress.It is wise to save the initial state so that you can restore it at any time to perform parameter studies.savetrench.savWe can change the current view from GravV to Trench with the commandplot current TrenchNow we can excavate a trench in the soil. First, typepropcoh=1e3 tens=1e3This will set the cohesion and tensile strength for all zones to 1000 Pa. These valuesfor strength arehigh enough to prevent failure in our initial state (i.e., unexcavated), but you shouldalways checkfor possible failure in the initial state by performing a few calculation steps. Toexcavate the trench,entermodel null range x=2,4 y=2,6 z=5,10With a low cohesion and vertical unsupported trench walls, collapse should occur. Because wewant to examine this process realistically, the large-strain logic is specified. This isdone by typingset largeFor plotting purposes, we wish to see only the change in displacements from the trench excavation, and not from the previous gravitational loading, so we zero out the x-, y- and z-displacement components:inixdis=0 ydis=0 zdis=0We purposely set the cohesion low enough to result in failure, so we do not want to use the SOLVE command with a limit for out-of-balance force (which checks for equilibrium). Oursimulation willnever converge to the equilibrium state. Instead, we can step through the simulationprocess onetimestep at a time, and plot and print the results of the collapse as it occurs. This is thereal powerof the explicit method. The model is not required to converge to equilibrium at eachcalculationcycle because we never have to solve a set of linear algebraic equationssimultaneously, as is thecase for implicit codes, with which many engineers are familiar.we use the STEP command: step 2000第三章FLAC 3D基础知识gridpointzonehorizontal boundary stressstructural cables(tiebacks)model boundaryinternal boundaries(excavation)roller bottom boundaryNamed ObjectsMacro Object—Typically, such an object contains a long, complex string that may be used repeatedly in the model. The pre-processor compares a string of command tokens to the list of defined macros and replaces any matching macro object with its fully expanded contents.macro Pt0 ’p0 0 0 0’macro Pt1 ’p1 add 10 0 0’macro Pt2 ’p2 add 0 10 0’macro Pt3 ’p3 add 0 0 10’macroModel_Size ’size 4 5 6’macroBig_Brick ’zone brick Pt0 Pt1 Pt2 Pt3 Model_Size’.genBig_Brick.macro ’Pt0’ ’p0 15 15 15’genBig_BrickThis pre-processing has two effects:(1) macro objects may be nested (but not recursively); and(2) the macro object name is removed from the command string.Model Object—Model objects, such as ranges in space, groups of zones in a model, or plot views, can be given userdefined names. Those objects can then be referred to by their names.gen zone brick size 6 6 6group Tunnel range x 1 5 y 0 6 z 1 5modelmohr..modelnul range group Tunnel.The named range and the named group are two very different model objects. The range pertains toa specified volume of space (or range of values), whereas the group identifies acollection of finitedifference zones in the model.Sign ConventionsDIRECT STRESS —Positive stresses indicate tension; negative stresses indicate compression.第四章初级实体建模技术Grid generation is performed via the GENERATE command and associated keywords that both define the number of zones in a model and shape the grid to fit a specified problem region.The number of zones is specified by the size keyword.It is best to start with a grid that has few zones (say, 1000 to 1500) to perform simple test runs andmake refinements to the grid. Then, increase the number of zones to improve theaccuracy.Using actual coordinatesgen zone brick size 6,8,8 p0 -10, -10, -20 &p1 10, -10, -20 &p2 -10, 10, -20 &p3 -10, -10, 0plot surfOnly four corners are required to define a parallelepiped-shaped mesh. More corners can be specifiedto define an irregular surface. Example 2.14 shows how to make a sloping surface atthe top of themesh.gen zone brick size 6,8,8 p0 -10, -10, -20 &p1 10, -10, -20 p2 -10, 10, -20 &p3 -10, -10, 0 p4 10, 10, -20 &p5 -10, 10, 10 p6 10, -10, 0 &p7 10, 10, 10plot surfIn the tutorial example, we noted that the boundaries of the model were influencing the results (see Figure 2.6). The boundary must be placed far enough away from the excavation to reduce these effects. A gradually graded mesh can be created in FLAC3D to move the model boundaries farther out without significantly increasingthe number of zones. For example, the command GEN zone radbrick creates a radially graded mesh around a brick-shaped mesh. The command in Example 2.15 creates a 3 ×5 ×5 zone brick-shaped mesh surrounded by a 7-zone radially graded mesh.gen zone radbrick&p0 (0,0,0) p1 (10,0,0) p2 (0,10,0) p3 (0,0,10) &size 3,5,5,7 &ratio 1,1,1,1.5 &dim 1 4 2 fillplot surfThe x,y,z coordinate system in FLAC3D is always right-handed and, as a default, the z-axis is drawn in the vertical direction on the screen. In Example 2.14 we assumed the z-axis was pointing in the vertical direction. However, we do not have to interpret the z-axis to mean the up direction. For Example 2.15, we will assume that the y-axis is the vertical direction. As long as we define the model in a right-handed system, we can create the grid in any direction we desire.The size keyword, as used in Example 2.15, specifies the number of zones in the brick and the number radially surrounding the brick (see Figure 2.11). The keyword ratio is given to manipulate the grid spacing. The four values that follow ratio are geometric ratios between successive zone sizes. The first three values are ratios for the zones in the brick, and the fourth value is the ratio for the zones surrounding the brick. In Example 2.15 above, the ratio is 1.0 for the brick zones and1.5 for the zones surrounding the brick. This causes each successive ring of zones surrounding the brick to be 1.5 times larger in the radial direction. The dim keyword defines the dimensions of the brick region (i.e., 1 m ×4 m ×2 m). The fill keyword fills the brick region with zones. If fill is omitted, no zones will be generated within the brick region.Notice that size, ratio and dim all refer to local axes as defined by p0, p1, p2, p3 in Figure 2.11, not to the global x,y,z-axes.Creating a model by reflecting elements on planes of symmetrygen zone radbrick&p0 (0,0,0) p1 (10,0,0) p2 (0,10,0) p3 (0,0,10) &size 3,5,5,7 &ratio 1,1,1,1.5 &dim 1 4 2 fillgen zone reflect dip 0 dd 90gen zone reflect dip 90 dd 90plot surfdip 为倾角的意思，其值大小为面与xy面所夹的倾角，dd为倾向，其值大小为面的法线在xy平面上的投影与y轴的夹角。
FLAC3D500培训
1. FLAC3D基本操作方法
pyramid gen zone pyramid size 6 6 6 p0 0 0 0 p1 6 0 0 p2 0 6 0 …
p3 0 0 6 p4 6 6 0 plot zone
1. FLAC3D基本操作方法
tetrahedron gen zone tetrahedron size 6 6 6 p0 0 0 0 p1 6 0 0 p2 0 6 0 …
在FLAC3D中，模型的建立通过关键词generate来实现，其基本格 式为： gen keywords1 keywords2 keywords3 …
For example: gen zone brick size 6 6 6 p0 0 0 0 p1 6 0 0 p2 0 6 0 … p3 0 0 6 p4 6 6 0 p5 0 6 6 … p6 6 0 6 p7 0 0 6 … (ratio 1 1 1 ) (dim 2 2 2) (fill)
在利用FLAC3D软件进行数值模拟时，主要是通过命令流来实现的。命令 流文件一般以txt或dat格式存储，并在命令输入窗口、菜单栏或快捷图标通过 call命令进行调用。
FLAC3D命令流文件需要 遵循一定的格式和语法要求， 在满足这些要求的前提下，命 令流文件的编写又是十分自由 灵活的，可根据用户个人的需 求自由编写。
p3 0 0 6 dim 2 4 2 ratio 1 1 1 1.2 (fill) plot zone
1. FLAC3D基本操作方法
radcylinder gen zone radcylinder size 6 6 6 12 …
p0 0 0 0 p1 6 0 0 p2 0 6 0 p3 0 0 6 dim 2 2 2 2 … ratio 1 1 1 1.2 (fill) plot zone
FLAC3D5.00培训
2. Fish 函数
Fish 函数语句
选择语句 CASEOF 表达式 …默认语句 CASE n1 …表达式值为n1时的语句 CASE n2 …表达式值为n2时的语句 ENDCASE 循环语句 LOOP var (exp1, exp2) … ENDLOOP 或 LOOP WHILE 条件表达式 … ENDLOOP 命令语句 COMMAND … ENDCOMMAND
1. FLAC3D基本操作方法
数值计算一般流程
建立模型
通过外部导入或在FLAC3D中直
材料参 数 边界条 件及初 始条件
接建模的方式建立计算模型。
建立模 型
材料参数
材料本构 材料力学参数
边界条件及初始条件
速1. FLAC3D基本操作方法
建立模型 在FLAC3D中，模型的建立通过关键词generate来实现，其基本格 式为：
1. FLAC3D基本操作方法
建立模型
FLAC3D建模的基本思路为“堆积木”，即首先建立各种形状的
网格单元，最后将建立的网格单元组合在一起，生成可用于数值计算
的整体模型。 FLAC3D内置13种不同形状的网格，包括brick(砖形), cshell(圆柱 状壳网格), cylinder(圆柱状网格), cylint(圆柱状交叉网格), dbrick(退化 砖形网格), pyramid(锥形网格), radbrick(砖形辐射网格), radcylinder(圆柱状辐射网格), radtunnel(平行六边形状辐射网格), retrahedron(辐射网格), tunint(砖形交叉网格), uwedge(均匀楔形网格), wedge(楔形网格).
通过对称生成网格
Flac3D5.0教程
Flac3D5.0教程第⼆章完成第⼀个简单分析计算样例by typing the commands from the keyboard, pressingat the end of each command line, and seeing the results directly.newgen zone brick size 6 8 8（This command will create an initial mesh that is six zones in the x-direction, eight zones in the y-direction and eight zones in the z-direction. For our model, the z-axis is oriented in the verticaldirection.）Plot（the Plot Base/0>prompt will appear. As long as this prompt appears, any subsequentcommands will be associated with the PLOT command. The plot view is identified as Base/0,which is the default view.）create Trenchadd surface yellowadd axes blackshowNow, give the zones a material model and properties. For this example, we use the Mohr-Coulombelastic-plastic model. Go back to the Flac3D>prompt in the command window andtype in thefollowing command:modelmohrThis will specify the Mohr-Coulomb model. Every zone in the grid could conceivably have adifferent material model and property. However, by not specifying a range of zonesafter the MODEL command, FLAC3D assumes that all zones are to be Mohr-Coulomb material.prop bulk = 1e8 shear = 0.3e8 fric = 35propcoh = 1e10 tens = 1e10You see that very high cohesion and tensile strength values are given. These areonlyinitial values that are used during the development of gravitational stresses within the body.In effect, we are forcing the body to behave elastically during the development of theinitial insitustress state.* This prevents any plastic yield during the initial loading phase of theanalysis.For this problem, loading is due to gravity. To apply gravity, use the commands setgrav 0, 0, -9.81ini dens = 1000In order to develop a gravitational body force, themass density must also be initialized. The INI command is used to initialize the mass density to1000 kg/m3 for all zones in the model.Next, the boundary conditions for the problem are set. At the Flac3D>prompt, type fix x range x -0.1 0.1fix x range x 5.9 6.1fix y range y -0.1 0.1fix y range y 7.9 8.1fix z range z -0.1 0.1With these commands, roller boundaries are placed on five sides of the model. The boundaries are “fixed” only in the specified direction (i.e., no displacement or velocity is allowed). The FIX commands perform the following functions.1. The gridpoints along the boundary planes at x = 0 and x = 6 are fixed in the x-direction. These two planes fall within the coordinate ranges specified by the range keywords for the first two FIX commands.2. The gridpoints along the boundary planes at y = 0 and y = 8 are fixed in the y-direction. These planes fall within the ranges specified for the third and fourth FIX commands.3. The gridpoints along the bottom boundary (z = 0) are fixed in the z-direction. This plane falls within the range for the fifth FIX command.We wish to monitor the change in the values of selected variables in the model during the calculational stepping. A HISTORY command can assist in helping us determinewhether a stable equilibrium solution or unstable collapse is occurring. We type the following commands:hist n = 5histunbalhistgpzdisp 4,4,8We choose to monitor the change in variables every five calculation steps. It is always a good idea to monitor the maximum unbalanced force in a model. If the unbalanced force approaches a very small value and displacement histories become constant, this indicates that an equilibrium state is reached.To allow gravitational stresses to develop within the body, we timestep the simulation to equilibrium.Here the SOLVE command is used to detect equilibrium automatically.setmech force=50solveWhen the unbalanced force falls below the limiting value (a limiting force of 50 N is specified with the SET command), the run will stop.* The plots are updated, since they are still visible on the screen. Shutting down the plots will cause the model to cycle faster.plothist 1hist 2The unbalanced force history approaches zero, andthe displacement history becomes constant; both are indicators that an equilibriumstate has beenreached.Note that each history is numbered sequentially from 1 as it is entered via the HIST command. Return to the Flac3D> prompt and typeprinthistfor a listing of the histories and their corresponding numbers.Plotcreat trenchadd contour dispadd axes blackshowclearaddbcontourszzadd axesplot create GravVplot set plane dip=90 dd=0 origin=3,4,0plot set rot 15 0 20plot set center 2.5 4.2 4.0plot add bound behindplot add bcontszz planeplot add axesplot showThis sequence will create a view, which we have called GravV, and make it the current view. We then set a plane for that view oriented at a dip angle of 90? (from the xy-plane, assuming that negative-z is “down”), a dip direction of 0?(measured clockwise from the positive y-axis in the xy-plane) and with one point on the plane at (x = 3, y = 4, z = 0). We add a wire-frame boundary plotted behind the plane and a block contour plot of the vertical stress component, σzz, on the plane. Finally, the model axes are added. The block contour plot, as opposed to an interpolated contour plot, displays the value of the stress calculated at each zone centroid. The color of each zone corresponds directly to the zone-based stress.It is wise to save the initial state so that you can restore it at any time to perform parameter studies.savetrench.savWe can change the current view from GravV to Trench with the commandplot current TrenchNow we can excavate a trench in the soil. First, typepropcoh=1e3 tens=1e3This will set the cohesion and tensile strength for all zones to 1000 Pa. These valuesfor strength arehigh enough to prevent failure in our initial state (i.e., unexcavated), but you shouldalways checkfor possible failure in the initial state by performing a few calculation steps. Toexcavate the trench,entermodel null range x=2,4 y=2,6 z=5,10With a low cohesion and vertical unsupported trench walls, collapse should occur. Because wewant to examine this process realistically, the large-strain logic is specified. This isdone by typingset largeFor plotting purposes, we wish to see only the change in displacements from the trench excavation, and not from the previous gravitational loading, so we zero out the x-, y- and z-displacement components:inixdis=0 ydis=0 zdis=0We purposely set the cohesion low enough to result in failure, so we do not want to use the SOLVE command with a limit for out-of-balance force (which checks for equilibrium). Oursimulation willnever converge to the equilibrium state. Instead, we can step through the simulationprocess onetimestep at a time, and plot and print the results of the collapse as it occurs. This is thereal powerof the explicit method. The model is not required to converge to equilibrium at eachcalculationcycle because we never have to solve a set of linear algebraic equationssimultaneously, as is thecase for implicit codes, with which many engineers are familiar.we use the STEP command: step 2000第三章FLAC 3D基础知识gridpointzonehorizontal boundary stressstructural cables(tiebacks)model boundaryinternal boundaries(excavation)roller bottom boundaryNamed ObjectsMacro Object—Typically, such an object contains a long, complex string that may be used repeatedly in the model. The pre-processor compares a string of command tokens to the list of defined macros and replaces any matching macro object with its fully expanded contents.macro Pt0 ’p0 0 0 0’macro Pt1 ’p1 add 10 0 0’macro Pt2 ’p2 add 0 10 0’macro Pt3 ’p3 add 0 0 10’macroModel_Size ’size 4 5 6’macroBig_Brick ’zone brick Pt0 Pt1 Pt2 Pt3 Model_Size’.genBig_Brick.macro ’Pt0’ ’p0 15 15 15’genBig_BrickThis pre-processing has two effects:(1) macro objects may be nested (but not recursively); and(2) the macro object name is removed from the command string.Model Object—Model objects, such as ranges in space, groups of zones in a model, or plot views, can be given userdefined names. Those objects can then be referred to by their names.gen zone brick size 6 6 6group Tunnel range x 1 5 y 0 6 z 1 5modelmohr..modelnul range group Tunnel.The named range and the named group are two very different model objects. The range pertains toa specified volume of space (or range of values), whereas the group identifies acollection of finitedifference zones in the model.Sign ConventionsDIRECT STRESS —Positive stresses indicate tension; negative stresses indicate compression.第四章初级实体建模技术Grid generation is performed via the GENERATE command and associated keywords that both define the number of zones in a model and shape the grid to fit a specified problem region.The number of zones is specified by the size keyword.It is best to start with a grid that has few zones (say, 1000 to 1500) to perform simple test runs andmake refinements to the grid. Then, increase the number of zones to improve theaccuracy.Using actual coordinatesgen zone brick size 6,8,8 p0 -10, -10, -20 &p1 10, -10, -20 &p2 -10, 10, -20 &p3 -10, -10, 0plot surfOnly four corners are required to define a parallelepiped-shaped mesh. More corners can be specifiedto define an irregular surface. Example 2.14 shows how to make a sloping surface atthe top of themesh.gen zone brick size 6,8,8 p0 -10, -10, -20 &p1 10, -10, -20 p2 -10, 10, -20 &p3 -10, -10, 0 p4 10, 10, -20 &p5 -10, 10, 10 p6 10, -10, 0 &p7 10, 10, 10plot surfIn the tutorial example, we noted that the boundaries of the model were influencing the results (see Figure 2.6). The boundary must be placed far enough away from the excavation to reduce these effects. A gradually graded mesh can be created in FLAC3D to move the model boundaries farther out without significantly increasingthe number of zones. For example, the command GEN zone radbrick creates a radially graded mesh around a brick-shaped mesh. The command in Example 2.15 creates a 3 ×5 ×5 zone brick-shaped mesh surrounded by a 7-zone radially graded mesh.gen zone radbrick&p0 (0,0,0) p1 (10,0,0) p2 (0,10,0) p3 (0,0,10) &size 3,5,5,7 &ratio 1,1,1,1.5 &dim 1 4 2 fillplot surfThe x,y,z coordinate system in FLAC3D is always right-handed and, as a default, the z-axis is drawn in the vertical direction on the screen. In Example 2.14 we assumed the z-axis was pointing in the vertical direction. However, we do not have to interpret the z-axis to mean the up direction. For Example 2.15, we will assume that the y-axis is the vertical direction. As long as we define the model in a right-handed system, we can create the grid in any direction we desire.The size keyword, as used in Example 2.15, specifies the number of zones in the brick and the number radially surrounding the brick (see Figure 2.11). The keyword ratio is given to manipulate the grid spacing. The four values that follow ratio are geometric ratios between successive zone sizes. The first three values are ratios for the zones in the brick, and the fourth value is the ratio for the zones surrounding the brick. In Example 2.15 above, the ratio is 1.0 for the brick zones and1.5 for the zones surrounding the brick. This causes each successive ring of zones surrounding the brick to be 1.5 times larger in the radial direction. The dim keyword defines the dimensions of the brick region (i.e., 1 m ×4 m ×2 m). The fill keyword fills the brick region with zones. If fill is omitted, no zones will be generated within the brick region.Notice that size, ratio and dim all refer to local axes as defined by p0, p1, p2, p3 in Figure 2.11, not to the global x,y,z-axes.Creating a model by reflecting elements on planes of symmetrygen zone radbrick&p0 (0,0,0) p1 (10,0,0) p2 (0,10,0) p3 (0,0,10) &size 3,5,5,7 &ratio 1,1,1,1.5 &dim 1 4 2 fillgen zone reflect dip 0 dd 90gen zone reflect dip 90 dd 90plot surfdip 为倾⾓的意思，其值⼤⼩为⾯与xy⾯所夹的倾⾓，dd为倾向，其值⼤⼩为⾯的法线在xy平⾯上的投影与y轴的夹⾓。
FLAC-FLAC3D基础与应用(结构单元)PPT课件
1
FLAC3D中的结构单元
• 有限单元 • 梁(beam)单元
beam
cable
• 锚索(cable)单元
• 桩(pile)单元
○ 锚杆: rockbolt
• 壳(shell)单元
shell geogrid
• 格栅(geogrid)单元
○ 土工织物；土工格栅
pile
liner
2
结构单元的应用
• Link可以与任何位置的
grid进行联系，而不一定
要与grid的坐标一致。 群桩 = 插秧
7
默认的连接属性
建模SEL结构模型时，程序自动建立结构 node与zone的连接 (node-zone links)
8
Node-Node Links
• SEL nodes 之间不会自动生成联系. • 必须手动设置node之间的联系 (e.g., beam and cable) 这
13
隧道与土体的相互作用
• 半圆隧道直径3.25m
• 上覆土层厚度5m
ht • 计算范围3r
r
• 土体弹性计算
○ (K=30MPa, G=10MPa)
hb
• 参数化编程
○ 几何尺寸
B
○ 模型参数
○ 网格形状
14
计算步骤
模型网格 计算结果
初始应力生成 施加管片
15
管片的连接
• 冷连接
○ 弯矩和剪力不能直接在环与环 间传递，只能通过其相邻的介 质传递
• 土与结构的相互作用
○ 桩基；基坑；边坡锚固 ○ 地下硐室的支撑结构；采矿；盾构 ○ 土工织物；土工合成材料
• 结构不宜复杂
○ 岩土工程软件，不宜单纯的结构分析
04_FLAC3D5.0_结构单元和接触面
3、结构单元的参数取值
某些结构单元参数的取值要视具体情况 而定，根据经验且必要时调整参数通过 试算来确定。
4、结构单元实例分析
• 4.1、简支梁（beam单元）承受两个相等集 中载荷
• 4.2、简支梁（shell单元）承受两个相等集 中载荷
4.1、简支梁（beam单元）承受两个相等集中 载荷
Simple Beam – Two Equal Concentrated Loads
2、结构单元的建模方法—线型结构单元
先建立节点再联接成单元的方法；
2、结构单元的建模方法—壳型结构单元
壳单元
2、结构单元的建模方法—壳型结构单元
def set_vals global ptA = 25.0 * sin( 40.0*degrad ) ; global ptB = 25.0 * cos( 40.0*degrad ) end @set_vals generate zone cylinder p0=( 0.0, 0.0, 0.0 ) & p1=( @ptA, 0.0, @ptB ) & p2=( 0.0, 25.0, 0.0 ) & p3=( 0.0, 0.0, 25.0 ) & p4=( @ptA, 25.0, @ptB ) & p5=( 0.0, 25.0, 25.0 ) & size=(1, 2, 2) sel shell id=5 range cylinder end1=(0.0, 0.0,0.0) & end2=(0.0,25.0,0.0) radius=24.5 not plot add zg plot ad sel geom delete zones ; delete all zones sel node init zpos add -25.0
FLAC3D5.0模型及输入参数说明教学文案
FL AC3 D5. 0 模型及输入参数说明模型参数代码可参考ma nua I中各个章节的comma nd命令及说明，注意单位。
用prop赋值。
各向同性弹性模型模型修正剑桥模型经典粘弹性模型1.1.14二分幕律模型5 mviscosity Maxwell 动力粘度，朮碎盐变形模型1.2模型适用说明遍布节理模型适用于Mohr-Coulomb材料来明确显示力在各个方向上的差异性。
双线性软化应变遍布节理模型综合了软化应变Mohr-Coulomb模型和遍布节理模型，这种模型包含面向矩阵和遍布节理的一个双线性断裂点集。
改进的Cam-clay 模型反映了形变度和抗破坏能力对体积变化的影响。
Mohr-Coulomb模型最适用于一般工程研究，同时，Mohr-Coulomb的内聚力和摩擦角参数相对于地质工程材料的其它属性，更容易获得。
软化应变和遍布节理塑性模型实际上是Mohr-Coulomb模型的变形，这些模型如果在附加材料参数的值较高时将得出与Mohr-Coulomb模型同样的结果。
Druck-Prager模型是一个相对于Mohr-Coulomb 模型的破坏标准的简化体，但是它一般不适于用来描述地质工程材料的破坏情况。
它主要是用来把FLAC3D与其它一些有Druck-Prager模型但却没有Mohr-Coulomb模型的数学软件作比较。
在摩擦力为零的时候请注意，此时Mohr-Coulomb模型退化为Tresca模型，而Druck-Prager 模型退化为Von Mises模型。
Druck-Prager模型和Mohr-Coulomb模型是计算起来效率最高的塑性模型，而其它的塑性模型在计算时却需要更多的内存和额外的时间。
例如，塑性应变不能在Mohr-Coulomb模型中直接计算出来（参见附录G）。
如果需要计算塑性应变，则必需要用应变软化模型。
这种模型主要是用于破坏后的情况对工程影响重大的工程活动中，如弯曲柱、开采塌落或回填研究。
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两种建模方式各有 各的优点，第二种 方式适合建立复杂 曲线结构单元（但 是要注意它不会自 动建立link！！若不 手动link就无任何作 用）
sel beamsel cid=3 id=1 node 3 4
➢ 桩单元
sel pile id 1 beg 0 0 0 end 0 0 10 nseg 4
2、结构单元的建模方法
• slide——大变形滑动标志
• pmoment——塑性矩，Mp • thexp——热膨胀系数，αt • ydirection——矢量Y
• slide_tol——大变形滑动容差 • ycomp——抗压强度(力) • density——密度
• thexp——热膨胀系数
3、结构单元的参数取值
某些结构单元参数的取值要视具体情况 而定，根据经验且必要时调整参数通过 试算来确定。
The shells can then be repositioned if ecessary by using the SEL node init command
2、结构单元的建模方法—注意事项
➢ FLAC3D是岩土工程的专业软件，因此一般很少用来做专门的结构 分析。在涉及到结构单元的问题中，往往都要考虑结构与周围的实 体单元的相互作用。在结构单元的建模时要特别注意一个基本原则： 一个zone至多包含一个structure node!
• gr_coh——单位长度上水泥浆粘结力cg
• xciy——梁结构y轴惯性矩, Iy • gr_fric——水泥浆的摩擦角φg
• xciz——梁结构z轴惯性矩，Ix • gr_k——单位长度上水泥浆刚度kg
• xcij——极惯性矩，J
• gr_per——水泥浆外圈周长Pg
• density——密度，ρ
➢ 结构单元由结构节点(node)和结构构件 (SELs)构成。
➢ 结构单元中的节点(node)可以与周围的实体 网格(zone)或其它结构节点建立连接(link)，
• 土工格栅(geogrid)
通过连接实现岩土体或结构与其它结构发生
• 衬砌单元(liner)
相互作用。
➢ 注意：结构节点并不是简单地与实体网格的
p1=( @ptA, 0.0, @ptB ) & p2=( 0.0, 25.0, 0.0 ) & p3=( 0.0, 0.0, 25.0 ) & p4=( @ptA, 25.0, @ptB ) & p5=( 0.0, 25.0, 25.0 ) & size=(1, 2, 2) sel shell id=5 range cylinder end1=(0.0, 0.0,0.0) &
➢ 锚索单元 sel cable id 1 beg 4 0 -1 end 5 0 -2 nseg 4
2、结构单元的建模方法—线型结构单 元
起始点坐标并给定分段数目的方法； 建立梁单元，并显示 单元坐标系！
2、结构单元的建模方法—线型结构单 元
ID号相同，共用Node，ID不同，各个ID对应的结构单元有各自独立的node。除非设 置联系，否则即使节点位于同一位置也不会传递力。
结构单元的显示！GUI操作和命令操作（manual）！ 调整好显示效果后可以将显示的命令文件另存出来，以备下次使用。（最适用于 几何模型相同，参数不同的，不同工况分析的比较）
2、结构单元的建模方法—线型结构单
元先建立节点再联接成单元的方；2、结构单元的建模方法—壳型结构单 元
➢ 壳单元
2、结构单元的建模方法—壳型结构单 元
1、结构单元的类型
FLAC3D中包含六种形式的结构单元，可以分成两类：
➢ 线型结构单元：
• 梁单元(beam) • 锚索单元(cable) • 桩单元(pile)
➢ 壳型结构单元：
• 壳单元(shell)
➢ FLAC3D中的结构单元是岩土工程中实际结 构的一种“抽象”，即采用简单的单元形式 来模拟复杂的结构体。
FLAC3D 5.0培训日程安排
1. FLAC3D V5.0界面操作 2. FLAC3D基本操作方法vs； 3. FLAC3D内置Fish语言的应用； 4. FLAC3D结构单元vs接触单元； 5. FLAC3D渗流模块 6. 其他
StructuralElement
FLAC3D结构单元
1. 结构单元的类型 2. 结构单元的建模方法 3. 结构单元的参数取值 4. 结构单元实例分析 5. 关于link
end2=(0.0,25.0,0.0) radius=24.5 not plot add zg plot ad sel geom delete zones ; delete all zones sel node init zpos add -25.0
2、结构单元的建模方法—壳型结构单 元
通过附着在实体网格表面来生成shell单元。
节点(gridpoint)建立联系，也不能建立node
与gridpoint之间的link
2、结构单元的建模方法
➢ 梁单元
sel beam id 1 beg 4 0 -1 end 5 0 -2 nseg 4
sel node id=1 0 0 0 sel node id=2 2 0 0 sel node id=3 4 0 -1 sel node id=4 5 0 -2 sel beamsel cid=1 id=1 node 1 2 ; sel beamsel cid=2 id=1 node 2 3
➢ 因此在建立线型结构单元时，要特别注意nseg变量的大小。nseg太 小则会导致计算不精确，而太大就会违反结构单元建模的基本原则。
3、结构单元的参数取值
➢ 梁单元
➢ 锚索单元
• emod——弹性模量，E
• emod——弹性模量， E
• nu——泊松比，ν
• xcarea——横截面积，A
• xcarea——横截面积，A
def set_vals global ptA = 25.0 * sin( 40.0*degrad ) ; global ptB = 25.0 * cos( 40.0*degrad )
end @set_vals generate zone cylinder p0=( 0.0, 0.0, 0.0 ) &