穿越软硬突变地层盾构隧道纵向地震响应振动台试验研究

发布时间：2019-05-19 20:37

【摘要】：为探讨穿越软硬突变地层盾构隧道纵向地震响应特性,基于纵向等效刚度模型,开展几何相似比为1∶40的振动台模型试验,研究软硬突变地层加速度以及隧道结构加速度、应变响应频谱特性,并采用数值模拟手段对试验结果进行验证。试验及计算结果显示:软硬突变地层及赋存其中的隧道结构加速度响应频谱曲线吻合较好,均表现出"双卓越频率"现象;输入地震频率接近坚硬地层主频时,软硬突变地层加速度放大倍率随埋深减小不再单调递增;软硬突变地层中结构应变显著增大,最大应变出现在地层软硬交界面软土一侧,隧道纵向应变增大区域分布于软硬地层交界面两侧2.5~3.5倍隧道直径范围内;应变响应从大到小依次为拱顶、拱底、拱腰,地层突变处隧道断面顶底应变差以及两侧拱腰应变差较均匀地层显著增大,软硬突变地层不仅增大了隧道纵向内力,也改变了其纵向整体弯曲方向。研究结果将为进一步揭示盾构隧道纵向地震响应特性及盾构隧道纵向抗、减震设计提供有益参考。
[Abstract]:In order to discuss the longitudinal seismic response characteristics of shield tunnel passing through soft and hard sudden change strata, based on the longitudinal equivalent stiffness model, the shaking table model test with geometric similarity ratio of 1:40 is carried out to study the acceleration of soft and hard abrupt formation and tunnel structure. The spectrum characteristics of strain response are verified by numerical simulation. The test and calculation results show that the acceleration response spectrum curves of the soft and hard abrupt formation and the tunnel structure are in good agreement with each other, and all of them show the phenomenon of "double excellent frequency". When the input seismic frequency is close to the main frequency of the hard formation, the acceleration magnification of the soft and hard abrupt formation does not increase monotonously with the decrease of the buried depth. In the soft and hard abrupt formation, the structural strain increases significantly, the maximum strain appears on the soft soil side of the soft and hard interface of the formation, and the longitudinal strain increase area of the tunnel is distributed in the range of 2.5 times 3.5 times the diameter of the tunnel on both sides of the interface of the soft and hard strata. The strain response from large to small is arch roof, arch bottom, arch waist, the strain difference between the top and bottom of the tunnel section and the strain difference between the two sides of the tunnel section at the sudden change of the strata are significantly larger than those of the uniform strata, and the soft and hard abrupt strata not only increase the longitudinal internal force of the tunnel. It also changes its longitudinal overall bending direction. The research results will provide a useful reference for further revealing the longitudinal seismic response characteristics of shield tunnel and the longitudinal resistance and damping design of shield tunnel.
【作者单位】：西南交通大学交通隧道工程教育部重点实验室;
【基金】：国家自然科学基金资助项目(51378433,51578457)~~
【分类号】：U455.43

【相似文献】