考虑G_(max)附加衰减的场地地震响应离心机试验数值模拟  

Numerical simulation for site seismic response of centrifuge model test considering effect of additional attenuation of G_(max)

作　　者：黄博[1] 李玲[1,2] 梁甜[1,3] 凌道盛[1] 

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,杭州310058 [2]东营市市级机关政府采购中心,山东东营257000 [3]中国水电顾问集团中南勘测设计研究院,长沙410014

出　　处：《岩土力学》2014年第7期2057-2063,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目(No.50908207;No.51178427;No.51278451)

摘　　要：在常规的场地地震响应有效应力分析法中,通常只考虑Gmax随有效应力和孔隙比的变化,而最新的试验研究表明,Gmax在大应变幅振动下存在附加衰减。收集了不同类型土体在大幅振动下的298组Gmax数据,拟合并给出了对应于两种Gmax附加衰减模式的计算模型,通过编制可考虑Gmax附加衰减影响的一维场地地震响应有效应力分析程序,分别对典型场地和离心机振动台模型场地的地震响应进行分析对比。结果表明:Gmax附加衰减对场地加速度和剪应力响应均有较大影响,将加速场地液化进程和扩大场地最终液化范围;考虑Gmax附加衰减可较好地模拟动力离心模型试验场地动力响应;但在强震情况下,场地迅速液化,Gmax附加衰减对场地动力响应的影响反而减弱。In the conventional effective stress method of site seismic response analysis, the changes of small strain shear modulus Gmax are only with the effective stress and void ratio. While the latest experimental studies show that under large amplitude vibration, there exists additional attenuation of Gmax. 298 groups of Gmax data of different types of soil under large amplitude vibration are collected and analyzed, based on which the computational equations corresponding to two additional attenuation modes of Gmax are provided. A one-dimensional site seismic response analytical program has been compiled based on effective stress principle, to account for the influence of additional attenuation of Gmax. A typical example and a dynamic centrifuge model test of sand field are separately simulated using the compiled program. It turns out that, the additional attenuation of Gmax has influence on both the response of accelerations and shear stresses. Besides, it can speed up the liquefaction of site and expand the final liquefied range. Numerical simulation of the centrifuge model test shows that, the acceleration and pore pressure responses are in good agreement with the experimental results when considering additional attenuation of Gmax. However, in case of strong acceleration, liquefaction comes soon, and the influence of additional attenuation of Gmax on site dynamic response becomes weakened instead.

关 键 词：小应变剪切模量Gmax 附加衰减 场地地震响应 有效应力分析法 

分 类 号：TU475.1[建筑科学—结构工程]