我想建一个2726~2770m深的地层，分三层，砂岩32m，泥岩4m，砂岩8m。施加应力，看不同岩层的地应力差异。可是建出来的效果很不好。请高手帮忙指点一下。文件如下：
gen zone brick p0 0 0 0 p1 60 0 0 p2 0 60 0 p3 0 0 44 &
p4 60 60 0 p5 0 60 44 p6 60 0 44 p7 60 60 44 size 60 60 44
group layer1 rang id 1 28800
group layer2 rang id 28801 43200
group layer3 rang id 43201 158400
model mohr
prop bu 1.2e6 sh 1.419e6 fric 43 ten 4.5e6 coh 3.5e6 range group layer1
prop bu 2.5e6 sh 1.419e6 fric 30 ten 3.5e6 coh 2.7e6 range group layer2
prop bu 1.2e6 sh 1.419e6 fric 43 ten 4.5e6 coh 3.5e6 range group layer3
ini density 2600 range group layer1
ini density 2600 range group layer3
ini density 2250 range group layer2
fix x range x -0.1 0.1
fix x range x 59.9 60.1
fix y range y -0.1 0.1
fix y range y 59.9 60.1
fix z range z -0.1 0.1
set grav 0 0 -10
set mech force=100
solve
app nstress sxx -5.2e7 range x -0.1 0.1
app nstress sxx -5.2e7 range x 59.9 60.1
app nstress syy -4.8e7 range y -0.1 0.1
app nstress syy -4.8e7 range y 59.9 60.1
app nstress szz -6.8e7 range z 43.9 44.1
plo set plane ori 0 1 0 norm 0 1 0
plo con sma plane
solve
