液化场地群桩基础地震反应离心机试验及损伤数值模型研究  

Seismic response of pile group foundations in liquefied sites based on centrifuge test and numerical simulation

作　　者：李雨润 闫志晓[1] 张健 LI Yurun;YAN Zhixiao;ZHANG Jian(College of Civil Engineering and Transportation,Hebei University of Technology,Tianjin 300401,China;Civil Engineering Technology Research Center of Hebei Province,Hebei University of Technology,Tianjin 300401,China)

机构地区：[1]河北工业大学土木与交通学院,天津300401 [2]河北工业大学河北省土木工程技术研究中心,天津300401

出　　处：《岩石力学与工程学报》2023年第1期212-223,共12页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51778207);河北省研究生创新培养资助项目(CXZZBS2022038)。

摘　　要：地基液化导致桩基础破坏是地震中建筑物和公共基础设施震害的主要原因。开展离心机振动台试验探究液化场地中直、斜群桩基础地震反应,并建立动静耦合边界非线性砂土液化大变形桩基塑性损伤有限元数值模型,进行地震作用下群桩基础的塑性反应分析。研究结果表明:地震作用下,地基土液化最先出现在群桩基础周围的地基土表面处,随着地震动峰值加速度的增大,液化范围逐渐向地基深处和桩基础两侧发展;群桩基础的动弯矩在桩底、地基土表面、承台嵌固位置较大;直群桩基础桩身变形较大位置出现在桩底部和地基土表面位置处,斜群桩变形较大位置则出现在桩身中间处;地基土超孔压比在地基浅层最大,并随输入地震动峰值增大而增大;地基土受地震动影响产生液化的同时,会在桩周20倍桩径范围内产生地基隆起,远桩区域产生地基震陷;地震作用下,直、斜群桩受压损伤较小,受拉损伤严重,0.3 g强震工况直、斜群桩桩底受拉破坏。Liquefaction-induced pile failure during earthquake is the main reason for building and public infrastructure damage.A centrifuge shaking table test was carried out to explore the seismic response of pile group foundations in the liquefaction sites.A finite element numerical model considering nonlinear liquefaction large deformation under dynamic static coupling,for carrying out plastic response analysis of pile group foundation under earthquake,was established.The research indicates that the liquefaction of the foundation under the action of an earthquake first appears on the surface of foundation around the pile.As the PBA increases,the liquefaction range of the foundation develops toward the depth of the foundation and both sides of the pile.The position of the maximum bending moment of pile group appears at the bottom of the pile,soil surface and caps.The larger deformation of the straight pile occurs at the bottom of the pile and the surface of the foundation,and the larger deformation of the oblique group piles appears in the middle of the piles.The excess pore pressure ratio of the foundation decreases with the foundation depth,but increases with the PBA.The foundation will produce foundation uplift within 20 times the pile diameter of the pile,and foundation seismic subsidence will occur in the far pile area.The group-pile suffers less compression damage and serious tensile damage.The pile bottom produces tensile failure during 0.3 g strong earthquake condition.

关 键 词：土力学 砂土液化 群桩基础 动力反应 塑性损伤 离心机振动台试验 数值模拟 

分 类 号：TU43[建筑科学—岩土工程]