地震液化对地铁工程的危害及对策

Hazard of Seismic Liquefaction for Metro Tunnel Structural Engineering and Countermeasures

研究目的:随着国内各大城市地下空间的不断开发和利用,大断面、浅埋地下结构越来越多,以往震害情况表明地铁结构容易遭受地震作用的破坏,地震中饱和砂土地层的液化是造成地铁结构破坏的重要原因之一,而目前国内外对于地铁地下结构的抗震研究,考虑地震液化的尚少,需研究并提出工程对策。研究结论:(1)地震液化对地铁隧道结构工程有很大的危害性,需采用合理的处理方式进行处理;(2)影响饱和砂土液化的主要因素有三大类:动荷条件、埋藏条件及土性条件;(3)具体工程中应根据液化地层埋藏深度、工程设置条件、工程类型等特点,通过采用控制结构埋深、采用地下连续墙围护型式、加强结构抗浮能力、考虑一定的地震作用附加内力等方式处理地震液化;(4)该研究成果可应用于城市轨道交通车站及隧道工程方案的经济比选及设计中。

Research purposes： With the development and utilization of underground space ol cities m tnma, ~arge sections and shallow underground structure are growing at the same time. The former seismic disaster shows that the metro structure can be easily destroyed by the earthquake. One of the main reasons for metro structures destroy is saturated sandy layers liquefaction. At present there is little anti - seismic research of metro underground structure on seismic liquefaction at home or aboard. Research conclusions： （ 1 ） Seismic liquefaction is very destructive for metro tunnel structural engineering. It should be solved carefully. （2）There are three main factors which affect the saturated sandy soil liquefaction which are dynamic load condition, embedding condition and soil texture condition. （3）The specific project should choose suitable methods which are based on buried depth of liquefaction formation, project settings and project type, to deal with seismic liquefaction. Seismic liquefaction can be solved by controlling burial depth, using underground continuous wall -enclosure, strengthening anti- floating ability of structure, and considering additional internal force which is caused by earthquake. （4）The result can be used for the technical and economic comparison in urban rail transit station and tunnel project.