new（上土钉墙+下桩锚复合支护）
generate zone brick p0 0 0 38 p1 10.8 0 38 p2 0 24 38 p3 0 0 40 p4 10.8 24 38 &
p5 0 24 40 p6 11.6 0 40 p7 11.6 24 40 size 10 12 2 ratio 0.95 1 1 group excavation1
generate zone brick p0 0 0 36 p1 10 0 36 p2 0 24 36 p3 0 0 38 p4 10 24 36 &
p5 0 24 38 p6 10.8 0 38 p7 10.8 24 38 size 10 12 2 ratio 0.95 1 1 group excavation2
generate zone brick p0 0 0 35.2 p1 10 0 35.2 p2 0 24 35.2 p3 0 0 36 p4 10 24 35.2 &
p5 0 24 36 p6 10 0 36 p7 10 24 36 size 10 12 1 ratio 0.95 1 1 group excavation3
generate zone brick p0 0 0 31.2 p1 10 0 31.2 p2 0 24 31.2 p3 0 0 35.2 p4 10 24 31.2 &
p5 0 24 35.2 p6 10 0 35.2 p7 10 24 35.2 size 10 12 4 ratio 0.95 1 1 group excavation4
generate zone brick p0 0 0 25.8 p1 10 0 25.8 p2 0 24 25.8 p3 0 0 31.2 p4 10 24 25.8 &
p5 0 24 31.2 p6 10 0 31.2 p7 10 24 31.2 size 10 12 5 ratio 0.95 1 1 group excavation5
generate zone brick p0 0 0 0 p1 10 0 0 p2 0 24 0 p3 0 0 25.8 &
p4 10 24 0 p5 0 24 25.8 p6 10 0 25.8 p7 10 24 25.8 size 10 12 12 ratio 0.95 1 0.95
generate zone brick p0 10 0 0 p1 60 0 0 p2 10 24 0 p3 10 0 25.8 &
p4 60 24 0 p5 10 24 25.8 p6 60 0 25.8 p7 60 24 25.8 size 20 12 12 ratio 1.05 1 0.95
generate zone brick p0 10 0 25.8 p1 60 0 25.8 p2 10 24 25.8 p3 10 0 31.2 &
p4 60 24 25.8 p5 10 24 31.2 p6 60 0 31.2 p7 60 24 31.2 size 20 12 5 ratio 1.05 1 1
generate zone brick p0 10 0 31.2 p1 60 0 31.2 p2 10 24 31.2 p3 10 0 35.2 &
p4 60 24 31.2 p5 10 24 35.2 p6 60 0 35.2 p7 60 24 35.2 size 20 12 4 ratio 1.05 1 1
generate zone brick p0 10 0 35.2 p1 60 0 35.2 p2 10 24 35.2 p3 10 0 36 &
p4 60 24 35.2 p5 10 24 36 p6 60 0 36 p7 60 24 36 size 20 12 1 ratio 1.05 1 1
generate zone brick p0 10 0 36 p1 60 0 36 p2 10 24 36 p3 11.6 0 40 &
p4 60 24 36 p5 11.6 24 40 p6 60 0 40 p7 60 24 40 size 20 12 4 ratio 1.05 1 1
model mohr
property bulk 2.96e6 shear 2.22e6 friction 10 cohesion 12e3 dilation 0 tension 1e10 density 1969 range z 35.5 40
property bulk 4.50e6 shear 1.50e6 friction 18 cohesion 25e3 dilation 0 tension 1e10 density 2041 range z 30.6 35.5
property bulk 32.41e6 shear 13.26e6 friction 40 cohesion 0 dilation 0 tension 1e10 density 2194 range z 24.7 30.6
property bulk 83.33e6 shear 31.95e6 friction 45 cohesion 0 dilation 0 tension 1e10 density 2245 range z 0 24.7
===========================
请问:下面设置的边界条件对吗？（这是基坑的一个剖面）
fix x range x -0.1 0.1
fix y range y -0.1 0.1
fix y range y 23.9 24.1
fix x y z range x 59.9 60.1
fix x y z range z -0.1 0.1
===========================
set gravity 0 0 -10
solve
property tension 0
solve
save initial.sav
================
new
restore initial.sav
initial state 0
initial xdisplacement 0 ydisplacement 0 zdisplacement 0
initial xvelocity 0 yvelocity 0 zvelocity 0
sel node initial xdisp=0 ydisp=0 zdisp=0
sel node initial xvel=0 yvel=0 zvel=0
model null range excavation1
请问：开挖土层之前需要建立结构单元，如土钉、混凝土面层等，怎么设置土钉和面层？是否需要设置接触面？如何设置？
