埋深组合群桩复合地基的沉降模式与模型试验验证

Settlement model and experiment of combined pile group composite foundation with embedded depth

采用理论分析和室内模型实验相结合的方法研究埋深组合群桩复合地基的沉降。研究结果表明:具有一定埋置深度的组合群桩复合地基受压后,桩间土顶面和桩顶面产生差异沉降,桩间土顶面沉降较大,长度和强度较大的桩顶面沉降较小;桩的长度和强度越大,桩顶面沉降越小,上刺入量越大;埋深组合群桩复合地基的沉降量等于桩顶沉降与桩顶垫层的压缩量之和,也等于桩间土顶面沉降量与土顶垫层的压缩量之和。具有一定埋置深度的组合群桩复合地基的p-s曲线呈缓变型,可以采用双曲线模型拟合,然后求得切线模量,再根据现行规范计算沉降。

Settlement of combined pile group composite foundation with embedded depth was studied by the method of theory analyses with indoor model experiments.The results show that,after being compressed,combined pile group composite foundation with embedded depth produces differential settlement between pile top and soil top,the top settlement of soil is larger and the one of longer and relatively strong pile is smaller.The bigger the length and strength of pile,the smaller the settlement of pile top,and the bigger the thrust amount of pile top.The settlement of the composite foundation is equal to the sum of settlement and cushion compression measure of pile top,and equal to the sum of settlement and cushion compression measure of soil top too.The settlement of the composite foundation varies gradually with pressure,and the p-s curve may be simulated by hyperbola curves so as to obtain tangent modulus and calculate settlement according to the current specification.