断层处应力无变异，不知道咋回事？

最近做了个隧道开挖的模型
加了条断层在里边
但是断层附近应力没变异
不知道啥原因
不知道有没有同仁遇到过类似情况
命令流如下
;-------------------------初始应力----------------------------------
mo mohr
set large
;------------------------------------------
def derive
s_mod=y_mod/(2.0*(1.0+p_ration))
b_mod=y_mod/(3.0*(1.0-2.0*p_ration))
end
;------------------------------------------
set y_mod=1.5e9 p_ration=0.32
derive
property bulk=b_mod she=s_mod &
fric 34 coh 0.6E+06 ten 0.3E+06 range group 1 any &
group 3 any group 5 any group 8 any group 9 any
;------------------------------------------
set y_mod=0.2e9 p_ration=0.38
derive
property bulk=b_mod she=s_mod &
fric 25 coh 0.2E+06 ten 0.05E+06 range group 2 any &
group 4 any group 6 any group 7 any
;------------------------------------------
ini density 2100 range group 1 any &
group 3 any group 5 any group 8 any group 9 any
ini density 1800 range group 2 any &
group 4 any group 6 any group 7 any
set grav 0 -10 0
;------------------------------------------
fix y range y -40.1 -39.9
fix x range x -40.1 -39.9
fix x range x 39.9 40.1
fix z range z -0.1 0.1
fix z range z 49.9 50.1
;------------------------------------------
apply syy -29.4e5 range y 39.9 40.1
ini syy -37.8e5 grad 0 2.1e4 0
ini sxx -17.788e5 grad 0 9.882e3 0
ini szz -17.788e5 grad 0 9.882e3 0
;------------------------------------------
hist unbal
plot hist 1
solve
save 111-dc-ini.sav
;-------------------------开挖----------------------------------
;把位移初始化为0
ini xdisp 0.0 ydisp 0.0 zdisp 0.0
;------------------------------------------
;开挖
model null range group 1
model null range group 2
model null range group 3
model null range group 4
model null range group 9
;------------------------------------------
solve
save 111-dc1-fin.sav