长水泥土桩-短碎石桩复合地基固结解析解  

Analytical solution for consolidation of composite ground with long cement-soil columns and short stone columns

作　　者：杨涛[1] 管柯君 李超 YANG Tao;GUAN Kejun;LI Chao(School of Environment and Architecture,University of Shanghai for Science and Technology,Shanghai 200093,China;College of Civil Engineering and Architecture,Zhejiang University,Hangzhou 310058,China)

机构地区：[1]上海理工大学环境与建筑学院,上海200093 [2]浙江大学建筑工程学院,杭州310058

出　　处：《上海理工大学学报》2021年第3期268-276,共9页Journal of University of Shanghai For Science and Technology

基　　金：国家重点研究发展计划(2016YFC0802405)。

摘　　要：基于轴对称固结模型并采用等竖向应变假设,给出瞬时荷载下长水泥土桩–短碎石桩复合地基的固结方程,推导出单面排水条件下复合地基的固结解析解,包括桩间土和碎石桩的平均超静孔隙水压力解和复合地基的整体平均固结度解。将固结度解析解与有限元数值解进行对比,证明了解析解的合理性。最后,利用固结度解对影响复合地基固结速率的主要因素进行了分析,研究了这种复合地基的固结特性。结果表明:碎石桩的贯入比是影响复合地基固结速率的最重要因素,贯入比的数值越大,复合地基固结越快。复合地基的固结速率随碎石桩渗透系数和置换率以及水泥土桩置换率和压缩模量的增加而逐渐增大,只有当碎石桩的贯入比较大时,其井组和置换率的变化才会对复合地基固结速率产生较大影响。碎石桩压缩模量的变化对复合地基固结速率的影响很小。Combining the axisymmetric consolidation model and the equal vertical strain assumption,differential equations governing the consolidation of a composite ground with long cement-soil columns and short stone columns subjected to an instant load were presented.The corresponding analytical solutions were derived under single-drainage condition,including the solution of average excess pore water pressures in the interior of a stone column and subsoil around a cement-soil column,and the solution of overall average degree of consolidation of the composite ground.Then,the proposed analytical consolidation solution was verified via the comparison with the numerical solution by the finite element method.Finally,some main influencing factors were analyzed to investigate the consolidation behavior of the composite ground.The results show that the penetration ratio of the stone columns(ratio of stone column length to soil thickness)is a crucial factor affecting the consolidation rate of the composite ground,and the higher the penetration ratio,the faster the consolidation of the composite ground.It increases gradually with the increase of the permeability coefficient and area replacement ratio of the stone columns,as well as the area replacement ratio and constrained modulus of the cement-soil columns.For the situation of higher values of penetration ratios,the variation of the well resistance and the area replacement ratio of the stone columns has obvious influence on the consolidation rate.The change in the constrained modulus of the stone columns has a limited effect on the consolidation rate of the composite ground.

关 键 词：复合地基 固结 解析解 碎石桩 水泥土桩 

分 类 号：TU473[建筑科学—结构工程]