45°倾角正断层粘滑错动对隧道影响试验分析

Modeling Experiment on Effect of Normal Fault with 45° Dip Angle Stick slip Dislocation on Tunnel

摘要:

通过1∶50室内模型试验，模拟了45°倾角正断层粘滑错动下，与之正交的隧道结构的受力变形破坏过程，并布置传感器监测了隧道顶部和底部的围岩压力、隧道轴向的应变和隧道环向的应变.结果表明，围岩压力在剪切带附近发生显著变化，上盘和剪切带范围内拱顶压力显著增大，下盘拱顶压力次之，上盘和剪切带隧道底部压力减小，下盘底部压力显著增大，隧道与下部围岩可能局部脱空以适应断层的剪切位移；上盘和剪切带范围内隧道纵向弯矩为正，下盘范围内为负，隧道偏心受压；以原型混凝土压坏来判定衬砌破坏，初步确定原型结构破坏所容许的最大断层位移D=0.7 m，理论上该值略偏大；隧道衬砌破坏区域长度，在剪切带和下盘范围分别为1.7和2.8倍隧道宽度.

Abstract:

The force deformation mechanism and failure process under the effects of stick slip dislocation of the normal fault with 45° obliquity was studied by a 1∶50 model experiment. And the strata pressure of the tunnel vault and bottom, axial strain and hoop strain were monitored. Results show that the strata pressure on the vault in the hanging wall and the shear zone increases significantly, followed by the pressure on the vault in the foot wall. The pressure on the tunnel bottom in the hanging wall and the shear zone decreases, while it greatly increases in the foot wall. The tunnel is separated from the wall rock so as to accommodate the shear displacement of the fault. The longitudinal bending moment in the hanging wall and the shear zone is positive and negative in the foot wall zone. By judging the lining failure from the cement prototype under compression, the maximum allowable fault displacement of the prototype is D=0.7 m. Theoretically, the value is overestimated. Tunnel lining fracture length is 1.7 and 2.8 times the width of the tunnel in the shear zone and foot wall respectively.