围岩的特征曲线,亦称为围岩的支护需求曲线。它形象的表明围岩在洞室周边所需提供的支护阻力及与其周边位移的关系。
2.求解
同一围岩级别下,相同隧道埋深情况下,通过改变衬砌的强度(修改体积模量及剪切模量)分别求解相应强度下隧道收敛平衡时的拱顶竖直位移和应力,根据所得数据绘制该围岩级别下相应埋深的围岩——支护特征曲线。
3.建模及计算要求
4.材料参数
表4-1 材料力学参数表
5.衬砌参数不变,埋深改变
import itasca as it
import matplotlib.pyplot as mpl
false")
# rock porperties of grade IV in N-m-s unit system
dens4 = 2600.0
E4 = 2.0e9
v4 = 0.3
coh4 = 0.15e6
fric4 = 30.0
# lining porperties in N-m-s unit system
densC = 2500.0
EC = 31.5e9
vC= 0.2
cohC = 3.2e6
fricC = 50.0
[] =
zstress = []
:
print(i)
buried_depth_inc = i*50
overburden = -1*dens4*9.81*buried_depth_inc
print(overburden)
it.command("""
model new
model largestrain off
zone import 'mesh.f3grid'
;赋予本构及参数
zone cmodel assign mohr-coulomb
zone property young {} poisson {} density {} cohesion {} friction {}
;赋予边界条件
zone face skin
zone face apply velocity-normal 0 range group 'west' or 'east'
zone face apply velocity-normal 0 range group 'south' or 'north'
zone face apply velocity-normal 0 range group 'bottom'
;设置重力并求解初始地应力
model gravity 9.81
zone initialize-stresses overburden {}
zone face apply stress-normal {}
model solve elastic
;清除初始位移、速度及塑性区
zone gridpoint initialize displacement (0,0,0)
zone gridpoint initialize velocity (0,0,0)
zone initialize state 0
;开挖及支护
zone cmodel assign null range group 'cut' or 'lining'
zone cmodel assign mohr-coulomb range group 'lining'
zone property young {} poisson {} density {} cohesion {} friction {} range group 'lining'
;求解
model solve
""".format(E4,v4,dens4,coh4,fric4,overburden,overburden,EC,vC,densC,cohC,fricC))
gpnt = it.gridpoint.near((25,0.5,59.7))
zpnt = it.zone.find(6686)
disp.append(-1.0*gpnt.disp_z())
zstress.append(-1.0*zpnt.stress()[2][2])
# 绘制围岩特征曲线
'black' ,linewidth = 1.0,marker = '*',markerfacecolor = 'red') =
curve of surrounding rock")
mpl.ylabel("stress/(Pa)")
mpl.xlabel("disp/(m)")
#C:\Users\18190\Desktop\case-01\为项目路径,根据实际路径进行替换
\Users\18190\Desktop\case-01\buried_depth.png', dpi=600) :
mpl.show()
图5-1 围岩特征曲线
6.埋深不变,衬砌参数改变
import itasca as it
import matplotlib.pyplot as mpl
false")
# rock porperties of grade IV in N-m-s unit system
dens4 = 2600.0
E4 = 2e9
v4 = 0.3
coh4 = 0.15e6
fric4 = 30.0
# lining porperties in N-m-s unit system
densC = 2500.0
EC = [31.5e10,31.5e9,31.5e8,31.5e7,31.5e6]
vC= 0.2
cohC = 3.2e6
fricC = 50.0
[] =
zstress = []
:
print(i)
print(EC[i])
it.command("""
model new
model largestrain off
zone import 'mesh.f3grid'
;赋予本构及参数
zone cmodel assign mohr-coulomb
zone property young {} poisson {} density {} cohesion {} friction {}
;赋予边界条件
zone face skin
zone face apply velocity-normal 0 range group 'west' or 'east'
zone face apply velocity-normal 0 range group 'south' or 'north'
zone face apply velocity-normal 0 range group 'bottom'
;设置重力并求解初始地应力
model gravity 9.81
zone initialize-stresses
model solve elastic
;清除初始位移、速度及塑性区
zone gridpoint initialize displacement (0,0,0)
zone gridpoint initialize velocity (0,0,0)
zone initialize state 0
;开挖及支护
zone cmodel assign null range group 'lining' or 'cut'
zone cmodel assign mohr-coulomb range group 'lining'
zone property young {} poisson {} density {} cohesion {} friction {} range group 'lining'
;求解
model solve
""".format(E4,v4,dens4,coh4,fric4,EC[i],vC,densC,cohC,fricC))
gpnt = it.gridpoint.near((25,0.5,59.7))
zpnt = it.zone.find(6686)
disp.append(abs(gpnt.disp_z()))
zstress.append(-1.0*zpnt.stress()[2][2])
# 绘制围岩特征曲线
'r' ,linewidth = 1.0,marker = '*',markerfacecolor = 'black') =
curve of surrounding rock")
mpl.xlabel("disp/(m)")
mpl.ylabel("stress/(Pa)")
#路径说明同上
\Users\18190\Desktop\case-01\E_changed.png', dpi=600) :
mpl.show()
图6-1 围岩特征曲线