关于临时仰拱受力问题

liuzhiqiang06

FLAC2D计算，上下两台阶开挖，上台阶加临时仰拱，开挖后临时仰拱内力比较大，下台阶开挖后临时仰拱内力却小了很多，尤其是轴力，不知其中原因，贴出命令流，请高手指正。
初始地应力：
config
grid 56,56
gen (-10.0,-10.0) (-10.0,10.0) (10.0,10.0) (10.0,-10.0) i 19 39 j 19 39
gen (-10.0,10.0) (-100.0,100.0) (100.0,100.0) (10.0,10.0) ratio 1.0,1.2 i 19 39 j 39 57
gen (-100.0,-100.0) (-100.0,100.0) (-10.0,10.0) (-10.0,-10.0) ratio 0.8333333,1.0 i 1 19 j 19 39
gen (-100.0,-100.0) (-10.0,-10.0) (10.0,-10.0) (100.0,-100.0) ratio 1.0,0.8333333 i 19 39 j 1 19
gen (10.0,-10.0) (10.0,10.0) (100.0,100.0) (100.0,-100.0) ratio 1.2,1.0 i 39 57 j 19 39
model elastic i=19,38 j=19,38
model elastic i=19,38 j=39,56
model elastic i=1,18 j=19,38
model elastic i=19,38 j=1,18
model elastic i=39,56 j=19,38
attach aside from 19 1 to 19 19 bside from 1 19 to 19 19
attach aside from 19 57 to 19 39 bside from 1 39 to 19 39
attach aside from 39 1 to 39 19 bside from 57 19 to 39 19
attach aside from 39 57 to 39 39 bside from 57 39 to 39 39
fix  y i 19 39 j 1
fix  x i 1 j 19 39
fix  x i 57 j 19 39
gen arc 0,1.963 0,6.1 70
gen arc 3.42,0 -4.66,0 -31
gen arc 3.42,0 -4.66,0 32
gen arc -0.992,-1.838 -4.038,-3.108 51
gen arc 0,1.52 0,-5.28 -16
gen arc 0,1.963 0,6.1 -70
gen arc -3.42,0 4.66,0 31
gen arc -3.42,0 4.66,0 -32
gen arc 0.992,-1.838 4.038,-3.108 -51
gen arc 0,1.52 0,-5.28 16
gen line -1.0,-2.099 1.0,-2.099
gen line -3.783,-3.6 -2.5,-3.6
gen line -2.5,-3.6 -1.0,-2.099
gen line 3.783,-3.6 2.5,-3.6
gen line 2.5,-3.6 1.0,-2.099
gen arc 0,12.106 0,0 -23
gen arc 0,12.106 0,0 23
group 'User:rock' notnull
model mohr notnull group 'User:rock'
def derive1
s_mod1=E_mod1/(2.0*(1.0+p_ratio1))
b_mod1=E_mod1/(3.0*(1.0-2.0*p_ratio1))
end
set E_mod1=2.502e9 p_ratio1=0.3
derive1
prop density=2000.0 bulk=b_mod1 shear=s_mod1 cohesion=840000.0 friction=30 notnull group 'User:rock'
set gravity=10
apply syy -6e6 from 19,57 to 39,57
solve elastic

上台阶+临时仰拱开挖
initial xdisp 0 ydisp 0
initial xvel 0 yvel 0
model null region 28 31
group 'null' region 28 31
group delete 'null'
struct node 1 grid 24,30
struct node 2 grid 24,31
struct node 3 grid 25,31
struct node 4 grid 25,32
struct node 5 grid 25,33
struct node 6 grid 26,33
struct node 7 grid 26,34
struct node 8 grid 27,34
struct node 9 grid 27,35
struct node 10 grid 28,35
struct node 11 grid 29,35
struct node 12 grid 30,35
struct node 13 grid 31,35
struct node 14 grid 31,34
struct node 15 grid 32,34
struct node 16 grid 32,33
struct node 17 grid 33,33
struct node 18 grid 33,32
struct node 19 grid 33,31
struct node 20 grid 34,31
struct node 21 grid 34,30
struct liner begin node 1 end node 2 seg 1 prop 5001
struct liner begin node 2 end node 3 seg 1 prop 5001
struct liner begin node 3 end node 4 seg 1 prop 5001
struct liner begin node 4 end node 5 seg 1 prop 5001
struct liner begin node 5 end node 6 seg 1 prop 5001
struct liner begin node 6 end node 7 seg 1 prop 5001
struct liner begin node 7 end node 8 seg 1 prop 5001
struct liner begin node 8 end node 9 seg 1 prop 5001
struct liner begin node 9 end node 10 seg 1 prop 5001
struct liner begin node 10 end node 11 seg 1 prop 5001
struct liner begin node 11 end node 12 seg 1 prop 5001
struct liner begin node 12 end node 13 seg 1 prop 5001
struct liner begin node 13 end node 14 seg 1 prop 5001
struct liner begin node 14 end node 15 seg 1 prop 5001
struct liner begin node 15 end node 16 seg 1 prop 5001
struct liner begin node 16 end node 17 seg 1 prop 5001
struct liner begin node 17 end node 18 seg 1 prop 5001
struct liner begin node 18 end node 19 seg 1 prop 5001
struct liner begin node 19 end node 20 seg 1 prop 5001
struct liner begin node 20 end node 21 seg 1 prop 5001
struct node 22 grid 33,30
struct node 23 grid 32,30
struct node 24 grid 32,29
struct node 25 grid 31,29
struct node 26 grid 30,29
struct node 27 grid 29,29
struct node 28 grid 28,29
struct node 29 grid 27,29
struct node 30 grid 26,29
struct node 31 grid 26,30
struct node 32 grid 25,30
struct liner begin node 21 end node 22 seg 1 prop 5002
struct liner begin node 22 end node 23 seg 1 prop 5002
struct liner begin node 23 end node 24 seg 1 prop 5002
struct liner begin node 24 end node 25 seg 1 prop 5002
struct liner begin node 25 end node 26 seg 1 prop 5002
struct liner begin node 26 end node 27 seg 1 prop 5002
struct liner begin node 27 end node 28 seg 1 prop 5002
struct liner begin node 28 end node 29 seg 1 prop 5002
struct liner begin node 29 end node 30 seg 1 prop 5002
struct liner begin node 30 end node 31 seg 1 prop 5002
struct liner begin node 31 end node 32 seg 1 prop 5002
struct liner begin node 32 end node 1 seg 1 prop 5002
struct prop 5001
struct prop 5001 e 3E10 height 0.30 width 1.0 pratio 0.23
struct prop 5002
struct prop 5002 e 3E10 height 0.30 width 1.0 pratio 0.23
set =large
history 999 unbalanced
solve

下台阶开挖
apply remove mech long from 29,35 to 29,35
model null region 28 28
group 'null' region 28 28
group delete 'null'
model null region 29 25
group 'null' region 29 25
group delete 'null'
struct node 33 grid 29,24
struct node 34 grid 30,24
struct node 35 grid 31,24
struct node 36 grid 32,24
struct node 37 grid 32,25
struct node 38 grid 33,25
struct node 39 grid 33,26
struct node 40 grid 33,27
struct node 41 grid 34,27
struct node 42 grid 34,28
struct node 43 grid 34,29
struct node 44 grid 28,24
struct node 45 grid 27,24
struct node 46 grid 26,24
struct node 47 grid 26,25
struct node 48 grid 25,25
struct node 49 grid 25,26
struct node 50 grid 25,27
struct node 51 grid 24,27
struct node 52 grid 24,28
struct node 53 grid 24,29
struct liner begin node 33 end node 34 seg 1 prop 5001
struct liner begin node 34 end node 35 seg 1 prop 5001
struct liner begin node 35 end node 36 seg 1 prop 5001
struct liner begin node 36 end node 37 seg 1 prop 5001
struct liner begin node 37 end node 38 seg 1 prop 5001
struct liner begin node 38 end node 39 seg 1 prop 5001
struct liner begin node 39 end node 40 seg 1 prop 5001
struct liner begin node 40 end node 41 seg 1 prop 5001
struct liner begin node 41 end node 42 seg 1 prop 5001
struct liner begin node 42 end node 43 seg 1 prop 5001
struct liner begin node 43 end node 21 seg 1 prop 5001
struct liner begin node 33 end node 44 seg 1 prop 5001
struct liner begin node 44 end node 45 seg 1 prop 5001
struct liner begin node 45 end node 46 seg 1 prop 5001
struct liner begin node 46 end node 47 seg 1 prop 5001
struct liner begin node 47 end node 48 seg 1 prop 5001
struct liner begin node 48 end node 49 seg 1 prop 5001
struct liner begin node 49 end node 50 seg 1 prop 5001
struct liner begin node 50 end node 51 seg 1 prop 5001
struct liner begin node 51 end node 52 seg 1 prop 5001
struct liner begin node 52 end node 53 seg 1 prop 5001
struct liner begin node 53 end node 1 seg 1 prop 5001
solve

liuzhiqiang06

怎么没人回答呢，顶起！