ABSTRACT

Sand liquefaction is considered to be one of the main causes of severe earthquake damage. The seismic response of large-scale underground structures is mainly controlled by the deformation of surrounding soils, and the large liquefaction-induced lateral displacement poses a serious threat to large underground structures. In this paper, a large-scale shaking table test is performed to simulate the dynamic interaction between liquefiable foundation, diaphragm wall and underground subway station. The results indicate that the interaction mode between soil and underground structure changes significantly with the different liquefaction states of surrounding soil. The underground structure improves the liquefaction resistance of adjacent lateral soils, but significantly reduces the liquefaction resistance of soils located directly below the structure. The development of dynamic pore pressure is related to the seismic intensity, and a significant dissipation of dynamic pore pressure usually occurs after the end of a strong seismic excitation. Moreover, the acceleration response law along the vertical direction has changed significantly within the buried depth of the underground structure. Specifically, the acceleration response of the lateral foundation is inhibited in the absence of liquefaction, but is enhanced in the complete liquefaction. In addition, the liquefaction states of model site also affect the spatial strain response of the underground structure.

摘要

沙土液化被认为是严重地震破坏的主要原因之一。大型地下结构的地震响应主要受控于周围土体的变形，液化引起的较大侧向位移对大型地下结构构成严重威胁。本文通过大型振动台试验模拟可液化地基、地下连续墙与地下地铁车站之间的动力相互作用。结果表明，随着周围土体液化状态的不同，土体与地下结构的相互作用方式发生显着变化。地下结构提高了相邻侧向土壤的液化阻力，但显着降低了位于结构正下方的土壤的液化阻力。动孔隙压力的发展与地震烈度有关，动孔隙压力的显着消散通常发生在强烈地震激发结束后。此外，在地下结构埋深范围内，垂直方向的加速度响应规律发生了显着变化。具体而言，横向基础的加速度响应在没有液化时受到抑制，但在完全液化时增强。此外，模型场地的液化状态也会影响地下结构的空间应变响应。在地下结构埋深范围内，垂直方向的加速度响应规律发生了显着变化。具体而言，横向基础的加速度响应在没有液化时受到抑制，但在完全液化时增强。此外，模型场地的液化状态也会影响地下结构的空间应变响应。在地下结构埋深范围内，垂直方向的加速度响应规律发生了显着变化。具体而言，横向基础的加速度响应在没有液化时受到抑制，但在完全液化时增强。此外，模型场地的液化状态也会影响地下结构的空间应变响应。