我想分析地下某一深度开挖一个水平孔（相当于隧道开挖不支护）引起的地表沉降，理论上是水平孔埋深越大地表沉降越小，但是我模拟的结果是埋深越大，地表沉降也越大，检查了很久也没发现问题所在，请给为指点一下，作为初学者的我不胜感激。附编写的程序：
埋深为5米的钻孔开挖程序：
new
gen zon radc dim 0.5 0.5 0.5 0.5 p0 0 ,0,0 p1 8,0,0
p2 0,2,0 p3 0,0,5 size 1 5 10 15 ratio 1 1 1 1.1 group 4
gen zon c p0 0,0,0
p1 0.5,0,0 p2 0,2,0 p3 0,0,0.5 p4 0.5,2,0 p5 0,2,0.5 size 2,5,10 group 1
gen
zone reflect orig 0 0 0 norm 0 0 1
gen zone reflect orig 0 0 0 norm 1 0
0
model mohr
prop bulk 19e6 shear 8e6 coh 9e3 fric 15 ten 0
ini dens
1790
fix x range x -8.1 -7.9;
fix x range x 7.9 8.1;
fix y range y
-0.1 0.1;
fix y range y 1.9 2.1;
fix z range z -5.1 -4.9;
set grav 0 0
-10
history n=50;
hist unbal;
pl hist 1
pl add con zd ou on
solve elas
model null range group 1
ini xdis=0 ydis=0 zdis=0
solve
step 50
hist gp zdis 0 0 5
hist gp zdis 1 0 5
hist gp zdis 5 0
5
solve
save c5.sav
埋深为7米的程序：
new
gen zon radc dim 0.5 0.5 0.5 0.5 p0 0 ,0,0 p1 8,0,0
p2 0,2,0 p3 0,0,7 size 1 5 10 15 ratio 1 1 1 1.1 group 4
gen zon c p0 0,0,0
p1 0.5,0,0 p2 0,2,0 p3 0,0,0.5 p4 0.5,2,0 p5 0,2,0.5 size 2,5,10 group 1
gen
zone reflect orig 0 0 0 norm 0 0 1
gen zone reflect orig 0 0 0 norm 1 0
0
model mohr
prop bulk 19e6 shear 8e6 coh 9e3 fric 15 ten 0
ini dens
1790
fix x range x -8.1 -7.9;
fix x range x 7.9 8.1;
fix y range y
-0.1 0.1;
fix y range y 1.9 2.1;
fix z range z -7.1 -6.9;
set grav 0 0
-10
history n=50;
hist unbal;
pl hist 1
pl add con zd ou on
solve elas
model null range group 1
ini xdis=0 ydis=0 zdis=0
solve
step 50
hist gp zdis 0 0 7
hist gp zdis 1 0 7
hist gp zdis 5 0
7
solve
save c7.sav
