饱和砂土中直群桩动力响应离心机振动台试验与简化数值模型研究  

Centrifugal shaking table test and numerical simulation of dynamic responses of straight pile group in saturated sand

作　　者：李雨润 闫志晓[1] 张健 黄达 LI Yurun;YAN Zhixiao;ZHANG Jian;HUANG Da(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》2020年第6期1252-1264,共13页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(51778207,51008110);河北省自然科学基金资助项目(E2018202107)。

摘　　要：饱和砂土液化场地高承台直群桩及土体横向动力响应分析一直是岩土工程抗震的热点和难点。针对这一问题,设计制作饱和砂土液化场地的2×2直群桩模型,进行离心机振动台试验,分析液化场地群桩–土动力响应规律。在此基础上,基于ABAQUS有限元软件平台,通过引入砂土液化大变形本构模型,采用有限元网格自适应调整技术克服大变形畸变问题,建立可液化场地群桩基础静动耦合非线性相互作用的二维有限元模型进行数值模拟分析,并用试验结果进行验证。结果表明:峰值加速度0.3 g正弦波工况下离心机振动台试验饱和砂土地基液化速度非常快,直群桩基础承台加速度与土中加速度放大峰值均不会超过输入波峰值,地基液化后承台加速度便开始衰减;饱和砂土地基超静孔隙水压力发展直接影响加速度响应,土体液化直接导致加速度衰减;数值模拟加速度结果与试验的加速度动力响应特性相符合,但量值上有区别,将数值模拟结果进行一定比例缩小后与试验结果基本吻合;数值模拟超静孔隙水压力与超静孔压比与试验结果基本一致,数值模拟显示浅层土较深层土液化明显;数值模拟的承台位移相较于试验偏保守。The analysis of lateral dynamic responses of high cap straight piles in saturated sand liquefaction sites is a hot and difficult point for geotechnical engineering.A 2×2 group straight pile model in saturated sand liquefaction sites was designed,and the centrifuge vibration test was carried out to analyze the dynamic responses of piles and soil in liquefaction sites.The sand liquefaction large deformation constitutive model was introduced into ABAQUS finite element software platform and the finite element mesh adaptive adjustment technique was used to overcome the large deformation distortion problem.A 2D finite element model for simulating the static and dynamic coupled nonlinear interaction of pile foundations in liquefiable sites was established and compared with the test.The test results show that,in the case of the sine wave with a peak acceleration of 0.3 g,the liquefaction rate of the saturated sand foundation is very fast.The peak accelerations of both the pile cap and the soil will not exceed the input wave peak,and the acceleration of the pile cap begins to attenuate after the ground liquefies.The development of the excess pore water pressure in saturated sand soil directly affects the acceleration response,and the liquefaction of soil directly leads to acceleration attenuation.The acceleration dynamic response behavior by numerical simulation is similar to that from the experimental test,and the scaled-down results of numerical simulation are approximately equal to the experimental results.The excess pore water pressure and the excess pore pressure ratio obtained from simulation and test are consistent.The simulation results also indicate that the shallow soil liquefies more obviously than the deep soil and that the displacement of the pile cap is smaller than that of the test.

关 键 词：土力学 离心机振动台试验 饱和砂土 直群桩 数值模拟 动力响应 

分 类 号：TU43[建筑科学—岩土工程]