FLAC模拟隧道开挖支护的实例

FLAC3D3.0在某隧道工程开挖支护中的应用

隧道建模命令流入下：
set log on
set logfile yang.log
gen zon radcyl p0 0 0 0 p1 9.0 0 0 p2 0 50 0 p3 0 0 8 &
size 4 20 6 4 dim 6 5 6 5 rat 1 1 1 1 group 围岩
gen zon cshell p0 0 0 0 p1 6.0 0 0 p2 0 50 0 p3 0 0 5.0 &
size 4 20 6 4 dim 5.6 4.6 5.6 4.6 rat 1 1 1 1 group 初期支护
gen zon cshell p0 0 0 0 p1 5.6 0 0 p2 0 50 0 p3 0 0 4.6 &
size 4 20 6 4 dim 5.0 4.0 5.0 4.0 rat 1 1 1 1 group 二次衬砌 fill group 原岩
gen zon radcyl p0 0 0 0 p1 0 0 -8.0 p2 0 50 0 p3 9.0 0 0 &
size 4 20 6 4 dim 3 6 3 6 rat 1 1 1 1 group 围岩2
gen zon cshell p0 0 0 0 p1 0 0 -3.0 p2 0 50 0 p3 6.0 0 0 &
size 4 20 6 4 dim 2.6 5.6 2.6 5.6 rat 1 1 1 1 group 仰拱初期支护
gen zon cshell p0 0 0 0 p1 0 0 -2.6 p2 0 50 0 p3 5.6 0 0 &
size 4 20 6 4 dim 2 5 2 5 rat 1 1 1 1 group 仰拱二次衬砌 fill group 仰拱原岩
gen zone reflect normal -1 0 0
gen zone radtun p0 0 0 0 p1 45 0 0 p2 0 50 0 p3 0 0 20 &
size 3 20 3 12 dim 9 8 9 8 rat 1 1 1 1.1 group 围岩3
gen zon reflect dip 0 ori 0 0 0 range x 0 9 y 0 50 z 8 20
gen zon reflect dip 0 ori 0 0 0 range x 9 45 y 0 50 z 0 20
gen zon reflect dip 90 dd 270 ori 0 0 0 range x 0 9 y 0 50 z 8 20
gen zon reflect dip 90 dd 270 ori 0 0 0 range x 0 9 y 0 50 z -8 -20
gen zon reflect dip 90 dd 270 ori 0 0 0 range x 9 45 y 0 50 z -20 20
gen zon brick p0 -45 0 -20 p1 -45 0 -40 p2 -45 50 -20 p3 45 0 -20 &
size 5 20 6 rat 1.1 1 1 group 围岩4
save tun_model.sav
假设围岩岩体符合mohr-coulomb本构模型，给围岩赋参数命令流如下，
; mohr-coulomb model
model mohr
def derive
s_mod1=E_mod1/(2.0*(1.0+p_ratio1))
b_mod1=E_mod1/(3.0*(1.0-2.0*p_ratio1))
s_mod2=E_mod2/(2.0*(1.0+p_ratio2))
b_mod2=E_mod2/(3.0*(1.0-2.0*p_ratio2))
end
set E_mod1=0.6e9 p_ratio1=0.27 E_mod2=0.8e9 p_ratio2=0.26
derive
prop bulk b_mod1 shear s_mod1 cohe 1.8e6 tens 0.8e6 fric 30 range z 4.5 20
prop bulk b_mod2 shear s_mod2 cohe 2.8e6 tens 1.0e6 fric 35 range z -40 4.5
ini dens=2300
set grav 0 0 -10
; boundary and initial conditions
apply szz -1.4e6 range z 19.9 20.1
fix z range z -40.1 -39.1
fix x range x -45.1 -44.9
fix x range x 44.9 45.1
fix y range y 49.9 50.1
hist unbal
hist gp xdis 6.0,0,0
hist gp zdis 0,0,5
hist gp xdis 6.0,50,0
hist gp zdis 0,50,5
plot hist 3
solve
save tun_nature.sav
对后面计算而言，模型建立时岩体在开挖前认为位移已经终了，因此需要对位移进行“清零”，而应力可以保留。假设隧道先开挖上断面，中间不设支护，直到进尺50m，那么此时位移和应力的分布情况可用如下命令流
ini xdis=0 ydis=0 zdis=0
plot re
model null range group 原岩
model null range group 二次衬砌
model null range group 初期支护
set large
hist unbal
plot hist 3
solve
save tun_ext1.sav
如果在开挖后适时对隧道进行锚喷混凝土初期支护，该命令流如下：
restore tun_nature.sav
ini xdis=0 ydis=0 zdis=0
plot re
mo

del null range group 初期支护
model null range group 二次衬砌
model null range group 原岩
step 100
hist unbal
plot hist 3
mo el range group 初期支护
prop bulk 1.33e9 shear 0.8e9 cohe 2.2e6 tens 1.2e6 fric 32 range z 4.5 7.0 x -7.0 7.0
prop bulk 10.9e9 shear 8.9e9 dens 2500 range group 初期支护
set large
solve
save tun_ext2.sav