穿越断层隧道节段衬砌结构破坏机理:试验与数值研究

Failure mechanism of segmental lining structure in fault-crossing tunnel:An experimental and numerical investigation

随着穿越活断层隧道工程建设的飞速发展,跨断层隧道的分析和设计方法迫切需要相应的理论指导。本研究通过振动台模型试验和数值模拟,探讨了断层位错和地面运动对不同长度管片衬砌结构的影响规律和破坏机制。结果表明,随着衬砌纵向连接刚度(节理和节段衬砌)的减小,上盘与断裂带之间的结构相对位移减小,而下盘与断裂带之间的结构相对位移变化趋势相反。因此,应根据工程要求将靠近上盘的衬砌段划分为较小的段,而靠近下盘的衬砌段应划分为较大的段。结合试验结果提出了断层附近影响带的设防范围。在划分分段长度时还应考虑衬砌接缝的作用,以便在断层位错的影响下实现纵线的平滑过渡。本文数值模拟的破坏演化过程与振动台试验结果吻合较好。

With the rapid development and construction of tunnel engineering across active faults,the analysis and design methods for crossing-fault tunnels urgently need appropriate theoretical guidance.Under the action of fault dislocation and ground motion,the influence law and failure mechanism of segmental lining structures with different lengths were explored via shaking table model test and numerical simulation.The results show that the structural relative displacement between the hanging wall and the fracture zone is reduced,accompanying by the decrease of lining longitudinal connection stiffness,while the variation tendency of structural relative displacement between the footwall and the fracture zone is to the contrary.Therefore,the lining segments near the hanging wall should be divided into smaller segments,and the lining segments near the footwall should be larger according to engineering requirements.Combined with the test results,the fortification range of the affected zone near fault is proposed.The function of lining joints should also be considered when dividing the length of segments,so that the smooth transition of longitudinal lines under the affection of fault dislocation can be realized.It is found that the failure evolution process of numerical simulation is well coincided with the result of shaking table test.