Fundamental study on seismic stability of tunnels in weakly cemented soil and its countermeasures

在弱胶结或无胶结土层中修建的隧道容易受到地震引起的位移或地面运动的破坏。为了研究此类隧道复杂的地震土-结构相互作用，发展了各种模型试验技术，如主动式剪切盒和断层模拟器。研究中考虑了三种具体情况，即：1）浅埋隧道受地层剪切变形的影响，2）软弱地层中隧道受大土压力的影响，3）冲积层中隧道受断层位移的影响。通过模型试验和数值模拟，分析了隧道的典型变形破坏机理，并探讨了有效的防治措施。

Tunnels in weakly cemented or no-cemented soils are susceptible to damages by ground motions or displacements caused by earthquake. In order to investigate complicated seismic soil-structure interaction of such tunnels, various model testing techniques has been developed, such as an active type shear box and a fault simulators. Three specific conditions were considered in this study, namely, 1) shallow tunnels which are subjected to shear deformation of grounds, 2) Tunnels in weak ground which is subjected to large earth pressure, and 3) tunnels in an alluvium subjected to fault displacement. From the model test results and numerical simulation, typical deformation and failure mechanism of these tunnels are scrutinized and effective countermeasures against them are discussed.