中文摘要：

针对目前上海地区第⑤2层砂质粉土的液化特性尚缺乏研究的实际问题，结合上海某电厂海底隧道的工程实例，基于动三轴试验，对场地内第⑤2层土体动力特性进行研究．内容包括往返作用力、固结压力、结构性、颗粒组成等因素对于液化特性的影响，确定了场地内饱和粉性土的抗液化强度指标等．通过Seed简化法，判别该土层地震液化可能性，给工程场地抗震设计及液化防治提供了科学依据，同时对类似工程的可液化场地处理可以有良好的借鉴．

英文摘要：

Based on a case study of underground projects at a power station in Shanghai area, the researches on the dynamic characteristics of liquefiable sandy silt are conducted by means of dynamic triaxial tests with a consideration of such influencing factors on liquefaction as cyclic stress, consolidation pressure, structure, particle composition and parameters for liquefaction evaluation are obtained. The seed simplified method is adopted to verify the results of the laboratory method. Some scientific conclusions on earthquake resistant design of this project are proposed and can be referred to the similar engineering projects of ground improvement for liquefaction mitigation