场地土层结构对砂土液化的影响研究——以新西兰液化场地为例  

Influence of sediment architecture on sand liquefaction:A case study on a liquefaction site in New Zealand

作　　者：王浩宇 王伟 李金宇 张晓庆 杨研科 徐凯放 熊文 WANG Haoyu;WANG Wei;LI Jinyu;ZHANG Xiaoqing;YANG Yanke;XU Kaifang;XIONG Wen(School of Geological Engineering,Institute of Disaster Prevention,Langfang 065201,China)

机构地区：[1]防灾科技学院地质工程学院,河北廊坊065201

出　　处：《自然灾害学报》2024年第6期98-108,共11页Journal of Natural Disasters

基　　金：中央高校基本科研业务费研究生科技创新基金项目(ZY20230312);中国地震局地震科技星火计划项目(XH23062A);中央高校基本科研业务费项目(ZY20180107)。

摘　　要：目前国内外已有的液化判别方法大多依据易液化土层自身的原位测试数据静态地计算场地液化势,而忽略了在实际地震动作用下,由于土层结构和土体物理力学参数不均匀分布的影响,孔隙水压力分布会发生动态变化,进而导致测试点液化势的变化。文中以2010—2011年间新西兰的坎特伯雷地震序列中的液化场地为例,基于新西兰岩土工程数据库提供的钻孔和静力触探资料建立典型液化场地凯什米尔高中(Cashmere High School,CMHS)的二维地质剖面,采用Flac软件对相应的场地模型进行数值模拟,研究土层结构和物理力学参数对场地砂土液化的影响机制。结果表明:砂质砾石层良好的渗透性可以有效地降低相邻液化砂土层的孔压累积,降低了砂土层的液化能力;黏土、粉质黏土等透水性差的土层有利于相邻液化砂土的孔压累积,促进了砂土液化的发生。因此,在砂土液化判别的方法中需要考虑液化土壤相邻土层的结构特征、渗透性等影响因素。Most existing liquefaction discrimination methods statically calculate the liquefaction potential at a site based on in situ test data of liquefiable soil but ignore the fact that the pore water pressure distribution varies dynamically under actual ground motion due to the influence of sediment architecture and uneven distribution of the physical and mechanical parameters of the soil,leading to a change in the liquefaction potential of the site.In this study,taking a liquefaction site affected by the Canterbury earthquake sequence in New Zealand during 2010—2011 as an example,a 2D geological profile of a typical liquefaction site in Cashmere High School(CMHS)was established based on borehole and cone penetration test data obtained from the New Zealand Geotechnical Database.The Flac software was applied to study the influence of sediment architecture and physical and mechanical parameters on the corresponding site model.The results showed that the sandy gravel layer can effectively reduce the pore pressure accumulation in the adjacent liquefied sandy soil layer owing to its good permeability,thereby reducing the liquefaction capacity of the sandy soil layer.Soils with poor permeability,such as clay and silty clay,facilitate the accumulation of pore pressure in the adjacent liquefiable sandy soil,promoting the occurrence of liquefaction.Therefore,it is necessary to consider the influence of sediment architecture characteristics,permeability and other factors of the adjacent layers in liquefiable soil when discriminating the liquefaction potential of sandy soil.

关 键 词：砂土液化 土层结构 静力触探 二维地质剖面 数值模拟 

分 类 号：TU435[建筑科学—岩土工程] X43[建筑科学—土工工程]