考虑桩体压缩变形的碎石桩复合地基非线性固结分析  

Analysis of Nonlinear Consolidation of Gravel Pile Composite Foundation Considering Compression Deformation of Pile

作　　者：赵明华[1] 陈侃[1] 刘猛[1] 顾美湘[1] 孙琮涵 

机构地区：[1]湖南大学岩土工程研究所,湖南长沙410082

出　　处：《公路交通科技》2015年第6期46-53,共8页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(51078138;51208191)

摘　　要：针对碎石桩复合地基固结研究的不足,通过引入土体压缩系数的e-lgσ'和渗透系数的e-lg k半对数模型,综合考虑碎石桩的固结压缩变形和桩身的井阻作用、扰动作用以及应力集中效应,建立出碎石桩复合地基非线性固结微分方程组,推导得到了非线性固结解析解。同时,针对各类因素对碎石桩复合地基平均固结度的影响进行了分析,结果表明:随着Cc/Ck的增大,碎石桩复合地基的固结速率减慢,但变化幅度不大。当Cc/Ck<1时,固结速率随均布荷载的增大而加快;当Cc/Ck>1时,固结速率随着均布荷载的增大而减慢;此外,桩、土压缩模量比的减小和土、桩渗透系数比的增大,均会降低碎石桩复合地基的固结速率,扰动区渗透系数的减小会显著减慢固结速率。通过工程实例和已有解析方法的对比分析,表明本文方法具有较好的合理性与可行性,且当碎石桩的渗透系数较小(即碎石级配较好)时,本文方法更适宜。For lack of researching consolidation of composite foundation of gravel piles, by introducing the elg σ＇ of compressibility coefficient of soil and the e-lg k semi-logarithmic model of permeability coefficient of soil, considering the consolidation compression deformation, of gravel piles and the well resistance, disturbance and stress concentration effects, the nonlinear consolidation differential equations of the gravel pile composite foundation is established, and the nonlinear consolidation analytical solution is derived. Meanwhile, all kinds of factors that affect the average consolidation degree of gravel pile composite foundation are analyzed. The result shows that （1） with the increase of Cc/Ck, the consolidation rate of gravel pile composite foundation slows down, but the variation is very small; （2） when C/Ck 〈 1, the consolidation rate speeds up with the increase of uniform load; （3） when C/Ck 〉 1, the consolidation rate slows down following the increase of uniform load; （4） the decrease of pile-soil compression modulus ratio and the increase of soil-pile permeability coefficient ratio will reduce the consolidation rate of gravel pile composite foundation, and the decrease of disturbance zone permeability coefficient will significantly slow down the consolidation rate. The comparative analysis between engineering examples and existing analytical solution shows that this method has preferable rationality and feasibility, and it is even more appropriate when thepermeability coefficient of gravel pile is small （ i. e. , the gradation of gravel is well）.

关 键 词：道路工程 碎石桩复合地基 半对数模型 非线性固结解析解 固结压缩变形 

分 类 号：U418.5[交通运输工程—道路与铁道工程]