降水后地表位移向上（附命令）哪错了？请指教

zhongbiao

随便试了个简单例子模拟水位下降对地面沉降的影响，但结果刚好相反 水位下降地面隆起，这是哪里错了呢？请大家帮助一下
new
config fluid
set fluid off
gen zone bri size 5 5 5
model mohr
prop bu 33e6 sh 7e6 c 0 f 30
ini dens 1500
model fl_iso
prop por 0.4 perm 10e-10
water density 1000
set grav 0 0 -10
water table ori 0 0 3 norm 0 0 1
ini fden 1000 ften -1e10
fix pp ran x -0.1 0.1
fix pp ran x 4.9 5.1
fix pp ran y -0.1 0.1
fix pp ran y 4.9 5.1
fix z ran z -0.1 0.1
fix x
fix y
solve
save wuluji1.sav
plot set plane ori 0 0 0 norm 0 1 0
plot con pp plane
ini xd 0 yd 0 zd 0 xv 0 yv 0 zv 0
set fluid on mech off
ini fmod 2e3 ften 0.0
fix pp 0 ran x 2 3 y 2 3 z 0 5
step 5000
set fluid off mech on
ini fmod 0
plot con zd plane
solve

lindeboge

渗流场为什么用step 5000，这样渗流场就稳定了吗，建议也用sol试试