西安地铁正交地裂缝隧道的模型试验研究

以西安地铁二号线穿越地裂缝的区间隧道为对象，通过几何相似比尺50:1的物理模型试验，开展了地裂缝活动条件下地铁隧道骑缝（变形缝与地裂缝一致）正交穿越地裂缝时衬砌结构与围岩相互作用机制的试验研究。结果表明，在地裂缝发生各级错动位移条件下，不同围岩应力场的围岩土压力、衬砌结构应力及其不均匀沉降位移变化规律相似；上下盘内的衬砌结构之间具有明显的错断位移，下盘内衬砌结构的沉降量越小，上盘内衬砌结构的沉降量越大，均呈渐变趋势；上盘内衬砌结构应力、围岩土压力随地裂缝错动位移的增加而减小，下盘衬砌结构应力和围岩土压力随地裂缝错动位移的增加而增大，围岩土压力和衬砌结构应力的增量峰值均发生在地裂缝附近。模型试验研究研究结果对于分析地裂缝活动区间地铁隧道工程的运营及维护具有重要的理论与实际意义。

Research on physical model experiment of Xi’an metro tunnel orthogonally crossing ground fissure

For the Xi’an metro line No.2 passing through ground fissure active zones, the interaction mechanism between lining and surrounding rock was studied by the physical model test, stimulating the metro tunnel orthogonally crossing the ground fissure and being consistent with the settlement crack of lining structure, with geometrical proportion of 50:1. Test results show that the regularity of wall rock pressure, stress and uneven settlement of lining structure changing with the relatively vertical deformation are similar under the different stress fields for the case of the settlement crack being consistent with the orthogonal ground fissure in strata. The relative settlement between two sections of lining structure with deformation crack at ground fissure develops apparently with the relatively vertical displacement between upper strata above ground fissure and lower strata below ground fissure. The lining structure is of large settlement in the upper strata and small settlement in the lower strata. The additional stress of lining structure and increasing value of earth pressure acting on lining structure is small in the upper strata and large in the lower strata. The maximum value of additional stress and earth pressure locates at the section closing to the ground fissure. When the ground fissure being of largely vertical displacement, the wall rock pressure on the bottom of lining structure in the upper strata decreases obviously or equals to zero. It could point out that the research of physical model experiment has importantly theoretical and practical significance to the construction of underground engineering and maintenance operation in the area of ground fissure.