岩土工程学报2017，Vol.39Issue(7)：1282-1291,10.DOI:10.11779/CJGE201707015
易液化深厚覆盖层地震动放大效应台阵观测与分析
Observations and analyses of site amplification effects of deep liquefiable soil deposits by geotechnical downhole array
摘要
Abstract
Based on the accelerations recorded from two downhole arrays instrumented by the Caltrans/CDMG project, the siteamplification effects of deep liquefiable soil deposits are analyzed in both time and frequency domains, and several importantfeatures of the wave propagation from the bedrock to the overlying soil layers are observed: (1) The depth of soil deposit affectsthe site amplification considerably, and large part of the amplification occurs in the near-surface zone within the depth of 20~30m; (2) The amplification differs from one to another direction, and the difference between the horizontal and vertical shakings issignificant; (3) The amplification occurs when the input bedrock motion is small, while the de-amplification effects areobserved when the bedrock input motion is large enough; (4) The amplification is frequency dependent, and the deep depositsamplify the bedrock ground motion in a wide frequency band. The underlying mechanisms are preliminarily analyzed. The simplified function accounting for the impedance contrast amplification and thickness attenuation effects is proposed based onthe plane wave assumptions, and the parameters are improved for the quarter wave length method. The amplification ratios arepredicted for all four events in conjunction with "free-surface effect", where the predictions are found in good agreement withthe observations either in time or frequency domain. The present study provides a theoretical basis and simplified method forestimating the ground motions for liquefaction evaluation and seismic design of deep liquefiable soil deposits.关键词
深厚覆盖层/地震动/放大效应/井下台阵/峰值加速度/反应谱/平面波Key words
deep deposit/ground motion/site amplification/geotechnical downhole array/peak acceleration/response spectrum/plane wave分类
建筑与水利引用本文复制引用
周燕国,谭晓明,陈捷,裴向军,陈云敏..易液化深厚覆盖层地震动放大效应台阵观测与分析[J].岩土工程学报,2017,39(7):1282-1291,10.基金项目
国家自然科学基金项目(51578501) （51578501）
浙江省自然科学基金项目(LR15E080001) （LR15E080001）
"国家特支计划"青年拔尖人才项目(2013) （2013）
国家重点基础研究发展计划("973"计划)项目(2014CB047005) （"973"计划）
地质灾害防治与地质环境保护国家重点实验室开放基金项目(SKLGP2015K017) （SKLGP2015K017）
