75°倾角正断层黏滑错动对公路隧道影响的模型试验研究

 通过1∶50室内模型试验，开展75°倾角正断层黏滑错动影响下隧道的受力变形机制研究，并监测隧道顶部和底部的地层压力、隧道轴向和环向应变。结果表明，地层的永久变形和地层–结构的相互作用，导致围岩压力在剪切带附近发生显著变化，上盘范围内拱顶压力显著增大，下盘拱顶压力次之，上盘隧道底部压力减小，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；上盘范围内为正，下盘范围内纵向弯矩为负；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 = 1.25 m，理论上该值略偏大。

MODEL EXPERIMENT ON EFFECT OF NORMAL FAULT WITH 75° DIP ANGLE STICK-SLIP DISLOCATION ON HIGHWAY TUNNEL

The paper conducts the research on the force-deformation mechanism under the effects of stick-slip dislocation of the normal fault with 75° obliquity by making use of 1∶50 model experiment. And the strata pressure of the tunnel vault and bottom，axial strain and hoop strain are monitored. Result shows that with the normal fault rupture propagating in the overburden layer，the tunnel structure which is orthogonal to the normal fault will undergo relatively big shear displacement. The strata permanent deformation and the interaction between the strata and the tunnel structure causes the formation pressure changes significantly，of which the pressure on the vault in the hanging wall zone increases significantly，followed by the pressure on the vault in the foot wall zone. The pressure on the tunnel bottom in the hanging wall zone decreases，while greatly increases in the foot wall zone. That leads the tunnel being possibly separated from the wall rock so as to accommodate the shear displacement of the fault. The longitudinal bending moment in the hanging wall zone is positive and negative in the foot wall zone. By judging the lining failure from the cement prototype under compression，the maximum allowed fault displacement of the prototype structure D = 1.25 m is determined. Theoretically，the value is overestimated.