利用地震动强度指标评价场地液化的离心模型试验研究  

Evaluation of soil liquefaction by ground motion intensity index by centrifuge model test

作　　者：周燕国[1] 谭晓明[1,2] 梁甜 黄博[1] 凌道盛[1] 陈云敏[1] ZHOU Yan-guo TAN Xiao-ming LIANG Tian HUANG Bo LING Dao-sheng CHEN Yun-min(MOE Key Laboratory of Soft Soils and Geoenvironmental Engineering, Institute of Geotechnical Engineering, Zhejiang University, Hangzhou, Zhejiang 310058, China Investment Development Co., Ltd, CCTEB, Wuhan, Hubei 430070, China PowerChina Zhongnan Engineering Corporation Limited, Changsha, Hunan 410014, China)

机构地区：[1]浙江大学软弱土与环境土工教育部重点实验室,浙江大学岩土工程研究所,浙江杭州310058 [2]中建三局投资发展有限公司,湖北武汉430070 [3]中国电建集团中南勘测设计研究院有限公司,湖南长沙410014

出　　处：《岩土力学》2017年第7期1869-1877,共9页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.51578501);浙江省自然科学基金资助(No.LR15E080001);“国家特支计划”青年拔尖人才项目(2013);国家重点基础研究发展计划(973)项目课题(No.2014CB047005);浙江大学曹光彪高科技发展基金资助(2014)~~

摘　　要：场地地震液化灾变(液化触发与震后变形)评价对基础设施抗震设计和安全服役有重要意义。为研究目前常用地震动强度指标IM的液化灾变评价能力,开展水平饱和砂土场地离心机振动台模型试验,对模型在50 g离心加速度下进行了20次不同幅值的振动,得到了液化与非液化响应数据。基于振动台台面输入建立峰值加速度a_(max)、地震剪应力比CSR、阿里亚斯强度I_a和累积绝对速度CAV_5的算法,并利用模型试验数据检验了这几种IM与液化触发和震后变形的相关性。分析表明,几类IM对液化触发的评价能力接近,且从超静孔压产生到初始液化触发都存在明显的IM阈值;几类IM对震后沉降评价能力有一定差异,其中I_a和CAV_5优于a_(max)和CSR,并对造成上述差异的原因做了初步分析。文中研究为选择合理的地震动强度指标评价场地液化灾变提供了科学依据。Evaluation of ground liquefaction hazards （e.g. the triggering and the post-liquefaction consequences） is essential for the seismic design and operational safety of infrastructures. To investigate the evaluation capability of different ground motion intensity measures （IM）, the present study conducts a series of dynamic centrifuge model tests under 50 g centrifugal acceleration. A level saturated sand model ground is shaken 20 times with different amplitudes of input motion to obtain both liquefied and non-liquefied case histories. Then the calculation procedures of the peak ground acceleration amax, the earthquake-induced cyclic stress ratio CSR, the Arias intensity Ia and the filtered accumulative absolute velocity CA V5 are presented based on the recorded base motion. All these IMs are processed and checked by the model test data. The analyses indicate that, several types of IMs have similar ability to evaluate the liquefaction triggering. There are obvious IM thresholds from the generation of excess pore pressure to the initial liquefaction trigger. Several types of IMs have differences in the evaluation ability of post-earthquake settlement. Ia and CA V5 perform better than amax and CSR, and the possible reasons are preliminary explained. This study presents basis for reliable evaluation of liquefaction catastrophe by selecting appropriate ground motion intensity index.

关 键 词：地震液化 离心模型试验 地震动强度指标 峰值加速度 地震剪应力比 阿里亚斯强度 累积绝对速度 

分 类 号：TU435[建筑科学—岩土工程]