穿越断层隧道地震响应规律动力对比试验研究

Comparison test of dynamic response characteristics of the tunnels through fault

为研究断层隧道在地震作用下的影响规律,开展了穿越断层隧道的振动台对比试验,介绍了试验材料、相似比选取及动力加载情况。试验表明:地震作用下衬砌腰侧的受力明显大于顶部和底部,在进行结构设计时应进行加强;隧道衬砌具有一定的加速度放大效应,衬砌结构的加速度傅里叶谱值主要集中于中低频,在结构临近破坏时,加速度和应变响应值将发生突变;隧道衬砌裂缝发展与结构位置密切相关,地震作用下底部裂缝由内向外发展,腰部裂缝由外向内发展;断层走向与隧道纵向夹角越小,地震对隧道的作用越大,裂缝的发育越明显;隧道的最终破坏形式为管节本身的纵向拉裂缝和管节接缝处的错台组成。该研究成果为穿越断层隧道的相关设计提供参考。

The shaking table comparison test was carried out to study the dynamic response of the tunnel through fault under earthquake. In this study, the test materials, choice of the similarity ratio and the dynamic loading conditions were introduced. Test results show that stress on the waist is obviously greater than that on the top and bottom of the tunnel lining under earthquake, which means the waist needs to be strengthened in design. The tunnel lining has a certain acceleration magnification effect. In addition, the main Fourier spectrum energy of the lining is concentrated in the middle and low frequency, and the acceleration and lining strain responses will change abruptly when the structure gets close to failure triggered by earthquake. The development of lining cracks is closely related to their location. Cracks at the bottom of the lining develop from the inside to the outside;however, cracks at the waist develop from the outside to the inside. The smaller the angle between the fault and axial direction of the tunnel is, the more obviously the cracks develop. The ultimate tunnel failure modes consist of longitudinal tensile crack and joint dislocation. This research results provide a reference for the relevant design of the tunnel through fault.