巨厚沉积土夹火山岩场地非线性地震反应特性  

Nonlinear seismic response characteristics of extremely deep deposit site with volcanic hard rock interlayers

作　　者：陈国兴[1,2] 李磊 丁杰发[1,2] 赵凯 CHEN Guo-xing;LI Lei;DING Jie-fa;ZHAO Kai(Institute of Geotechnical Engineering,Nanjing Tech.University,Nanjing,Jiangsu,210009,China;Civil Engineering and Earthquake Disaster Prevention Center of Jiangsu Province,Nanjing Tech.University,Nanjing,Jiangsu 210009,China)

机构地区：[1]南京工业大学岩土工程研究所,江苏南京210009 [2]南京工业大学江苏省土木工程防震技术研究中心,江苏南京210009

出　　处：《岩土力学》2020年第9期3056-3065,3076,共11页Rock and Soil Mechanics

基　　金：国家重点研发计划项目(No.2018YFC1504301)。

摘　　要：地震基岩深度和土体动力本构模型的选取对核岛场地地震效应评价结果的合理性具有重要影响。以拟建某沿海核电厂深度470 m沉积土夹火山岩层场地的3个钻孔剖面为研究对象,采用一维等效线性波传分析(ELA)法、基于Matasovic本构模型和Davidenkov-Chen-Zhao(DCZ)本构模型的一维非线性分析(NLA)法,选取不同剪切波速的5个岩土层作为地震基岩,研究了输入地震动特性、地震基岩深度和土体动力本构模型的选取对巨厚沉积土夹火山岩层场地非线性地震反应特性的影响。结果表明:(1)以浅层硬岩夹层或深部土层作为地震基岩,NLA法计算的5%阻尼比的地表谱加速度SA的短周期部分较之ELA法的计算值大,但两者计算的地表SA谱的长周期部分几乎一致;(2)基于Matasovic模型和DCZ模型的NLA法计算的地表SA谱谱形和峰值加速度随深度的变化趋势基本一致;(3)从NLA法计算的地表峰值加速度和累积绝对速度而言,以剪切波速约2500 m/s的浅层硬岩夹层作为地震基岩是适宜的。The depth to seismic bedrock and the nonlinear and hysteretic model of soil under cyclic loading have essential influences on the evaluation results of the nuclear island seismic site response.Using the one-dimensional(1D)equivalent linear wave propagation analysis(ELA)and nonlinear analysis(NLA)methods based on both the Matasovic and the Davidenkov-Chen-Zhao(DCZ)hysteretic models,three borehole profiles of 470 m depth with volcanic rock interlayer for the AP1000 nuclear plant located in the coastal deposits in China are selected to numerically simulate seismic site response.Five rock and soil layers with different shear wave velocities and depths are selected as the seismic bedrocks,the effects of input ground motion characteristics,the depth to seismic bedrock and the soil nonlinear and hysteretic model on the nonlinear site response characteristics of extremely deep deposit with volcanic hard rock interlayer are investigated.The results show that regardless of taking a shallow hard rock interlayer or a deep soil layer as the seismic bedrock,the 5%-damped surface spectral accelerations(SAs)at short periods calculated by the NLA method is greater than those calculated by the ELA method.However,the surface SAs at long periods calculated by the NLA and ELA methods are almost identical.Moreover,the curve shapes of surface SAs and peak accelerations along the soil depth calculated by the NLA method based on both the Matasovic and the DCZ models are basically consistent.Finally,from the surface peak ground acceleration and the cumulative absolute velocity calculated by the NLA method,it is suitable to select a shallow hard rock interlayer with the shear wave velocity of approximately 2500 m/s as the seismic bedrock.

关 键 词：巨厚沉积土场地 场地非线性地震反应 地震基岩 硬岩夹层 

分 类 号：TU435[建筑科学—岩土工程]