密实散体材料桩减轻液化触发微倾地层场地侧向变形研究  

Mitigation of liquefaction-induced lateral deformation in a slightly sloping stratum by dense granular column

作　　者：李平[1] 张宇东[1] 张建毅[1] 辜俊儒 周春澍 LI Ping;ZHANGYudong;ZHANG Jianyi;GU Junru;ZHOU Chunshu(Institute of Disaster-Prevention,Sanhe,Hebei 065201,China)

机构地区：[1]防灾科技学院

出　　处：《岩石力学与工程学报》2018年第A02期4320-4328,共9页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51508096);中国地震局地震科技星火计划项目(XH15067Y)~~

摘　　要：液化触发的微倾地层场地侧向变形将加重震害,密实散体材料桩能够有效减轻震害。本文聚焦密实散体材料桩置换率对该类型场地处理效果,在基于离心机模型试验和有限元(OpenSees)校核土体参数基础上,采用2D有限元模型(OpenSees)对该问题开展相关研究。研究结果表明:对于微倾砂土场地砂土液化将产生很大的侧向位移,而非液化土产生的侧向位移较小,砂土液化是导致较大侧向位移的主要原因;布设密实散体材料桩能够明显减轻液化触发的侧向变形,处理效果与桩的置换率有着密切关系,随着置换率的增加侧向位移明显减小。数值模拟表明当液化土厚度6m时置换率大于20%时,水平侧向位移趋于常数,这表明部桩置换率不同对微倾液化场地处理有效的深度也不同,因此使用该方法处理深厚微倾液化场地时要验算其有效深度,进而确定设计方案。Liquefaction-induced lateral spreading in slightly sloped sites may result in serious earthquake damage, and the dense granular column is used to mitigate this kind damage. The influence of improvement ratios in the treated sites was focused in this paper,then this problem was studied by 2D-FEA,based on the calibration of soil parameters using centrifuge test and 2D-FEA(OpenSees). The research results shown that as below,a large lateral deformation happened within the liquefied soil in the slightly sloped sites , but lateral deformation of non-liquefiedsoil layers were much smaller,so liquefaction is the main reason for large lateral deformation. Installation of dense granular column can mitigate liquefaction-induced lateral deformation in slightly sloped sites obviously. Improvement effectiveness has a close relationship with displacement ratios,furthermore lateral deformation were decreased obviously as displacement ratios increased. Numerical simulation results shown that the lateral deformation tend to be a constant when depth of liquefied soil was more than 6m and the displacement ratios was greater than 20%,it shown that there were different effective improvement depth with different displacement ratios,so the effective improvement depth should be calculated and checked when this method is used to improve slightly sloped liquefaction site,then determining the designing scheme.

关 键 词：土力学 OPENSEES 砂土液化 离心机试验 密实散体材料桩 侧向变形 地震工程 

分 类 号：TU43[建筑科学—岩土工程]