覆水液化场地群桩–土动力相互作用p-y曲线特性研究  

Study on p-y curve characteristics of pile group soil dynamic interaction in overlaying water liquefied sites

作　　者：兰天 李雨润 闫志晓 王永志[2] LAN Tian;LI Yurun;YAN Zhixiao;WANG Yongzhi(College of Civil Engineering and Transportation,Hebei University of Technology,Tianjin 300401,China;Key Laboratory of Earthquake Engineering and Engineering Vibration,Institute of Engineering Mechanics,China Earthquake Administration,Harbin,Heilongjiang 150080,China)

机构地区：[1]河北工业大学土木与交通学院,天津300401 [2]中国地震局工程力学研究所地震工程与工程振动重点试验室,黑龙江哈尔滨150080

出　　处：《岩石力学与工程学报》2025年第2期505-518,共14页Chinese Journal of Rock Mechanics and Engineering

基　　金：国家自然科学基金资助项目(52278340);河北省自然科学基金资助项目(E2023202028);河北省研究生创新资助项目(CXZZSS202409)~~。

摘　　要：强震引发的场地液化是造成桥梁震害的重要原因,由于现有研究主要集中在无上覆水的普通场地,忽略上覆水存在对桩土相互作用的影响,因此,采取离心机振动台试验结合数值模型的方法,通过p-y曲线特征分析覆水液化场地群桩–土动力相互作用规律。研究表明:(1)强震作用下,覆水场地桩周土刚度更大,呈现出一定的抗液化性;(2)有无覆水存在的场地液化过程相似,桩周土刚度呈现先减小后增大的趋势,覆水场地液化土体在超静孔压比稳定后,桩周土刚度恢复更慢;(3)随着上覆水深度的增加,土体的初始刚度不断增大,p-y曲线滞回圈包围面积减小,不利于振动能量的耗散;(4)当输入振动幅值较小时,上覆水会降低桩周土的刚度,放大超静孔压比;当振动幅值较大时,上覆水会增加桩周土的刚度,减小超静孔压比。研究成果为合理评价覆水液化场地桥梁桩土动力相互作用规律提供理论参考。Site liquefaction induced by significant seismic events constitutes a critical factor contributing to the structural damage observed in pile-supported bridge systems.Existing literature predominantly addresses typical sites that lack overlying water,thereby neglecting the implications of such water on pile-soil interaction dynamics.This investigation employs a centrifugal shaking table test,supplemented by numerical modeling,to elucidate the dynamic interaction characteristics between piles and soil within overlying water-liquefied contexts,utilizing p-y curves for analytical characterization.The results indicate that:(1)under substantial seismic loading,the soil stiffness surrounding piles in water-covered sites exhibits an increase,thereby demonstrating a degree of resilience to liquefaction;(2)the liquefaction processes in sites,regardless of the presence of overlying water,exhibit comparable characteristics,with the soil stiffness around piles initially diminishing before ultimately recovering;however,recovery in soil stiffness within water-covered liquefied sites occurs at a nominally slower ratesubsequent to the stabilization of the excess pore pressure ratio;(3) an increase in overlying water depthcorresponds to an elevation in the initial stiffness of the soil matrix while concurrently reducing the enclosed areaof the hysteresis loop of the p-y curve,which adversely affects the dissipation of vibrational energy;(4) at loweramplitudes of input vibration,the presence of overlying water reduces the stiffness of the soil surrounding thepile,thereby amplifying the excess pore pressure ratio;conversely,at higher vibration amplitudes,overlying waterincreases the soil stiffness around the pile and diminishes the excess pore pressure ratio. The findings of this studyprovide crucial theoretical insights for the comprehensive evaluation of pile-soil dynamic interaction mechanismsin bridges situated within water-influenced liquefaction zones.

关 键 词：土力学 覆水液化场地 群桩 P-Y曲线 离心机试验 数值模拟 

分 类 号：TU43[建筑科学—岩土工程]