摘要
为研究液化土体侧向扩展对群桩基础动力响应的影响,设计了可液化场地流动变形对桩基础地震反应影响的小型振动台模型试验。采用"钢带法"估计不同位置、不同类型场地地基土的侧向位移,探讨了地基土侧向流动速率与桩基结构地震内力的相关性,对比分析了上部结构惯性力及场地类型对桩身内力反应的影响,研究了由倾斜场地土体侧向扩展导致的群桩偏移运动。试验结果表明,桩周及下游土体的侧向位移随着土层深度的减小而逐步增大。可液化土体发生液化时所产生的流滑效应促使土体孔压加速消散。在水平场地条件下,土体侧向扩展沿土层深度方向线性分布;而倾斜场地条件下,土体的侧向扩展沿土层深度呈"抛物线型"分布。随着地基土液化,群桩基础受到的土体侧向约束力逐渐降低,进而使得群桩的峰值位移逐渐减小。
In order to study the influence of the lateral expansion of liquefied soil on the dynamic response of pile group foundation,a small-scale shaking table model test was designed for the influence of flow deformation of the liquefied site on the pile foundation seismic response.By using the "steel strip method",the lateral displacement of soils in different types of sites is estimated.The correlation between the lateral flow rate of the foundation soil and the seismic internal force of the pile foundation was discussed.The influence of the inertial force and site type on the internal force reaction of the pile body was compared and analyzed,and the pile group migration result from the lateral expansion in the sloping site was analyzed.The test results show that the lateral expansion of the soil around the pile and the downstream soil gradually increases from bottom to top along the depth direction.The effect of soil liquefaction and sliding on soil pore pressure dissipation can be promoted.The lateral displacement pattern of hori- zontal site is linear,while the distribution pattern of lateral displacement along the depth of sloping site is parabolic.The liquefaction of foundation soil weakens the lateral constraint of soil on pile group foundation,resulting in the decrease of the displacement amplitude of pile groups after liquefaction.
作者
沈吉荣
王志华
林文品
高洪梅
郭恩成
SHEN Jirong;WANG Zhihua;LIN Wenpin;GAO Hongmei;GUO Encheng(Urban Underground Space Research Center,Nanjing Tech University,Nanjing 210009,China)
出处
《自然灾害学报》
CSCD
北大核心
2018年第6期27-33,共7页
Journal of Natural Disasters
基金
国家自然科学基金项目(51378257
51678300)~~
关键词
砂土液化
液化流滑
侧向大变形
振动台试验
sand liquefaction
liquid flow
lateral deformation
shaking table test
