双向渗流下考虑应力时空效应的组合桩复合地基固结理论研究  

Theoretical study on consolidation of composite foundation with composite piles considering spatiotemporal effect of stress under bidirectional seepage

作　　者：张玉国[1] 杨文兵 赵雅纯 王闯 赵亚敏 ZHANG Yu-guo;YANG Wen-bing;ZHAO Ya-chun;WANG Chuang;ZHAO Ya-min(Institute of Civil Engineering,Zhongyuan University of Technology,Zhengzhou,Henan 450007,China)

机构地区：[1]中原工学院建筑工程学院,河南郑州450007

出　　处：《岩土力学》2024年第1期184-196,共13页Rock and Soil Mechanics

基　　金：国家自然科学基金(No.U1204511,No.51509274);河南省高等学校重点科研项目(No.19A560027);河南省自然科学基金面上项目(No.222300420596)。

摘　　要：碎石桩和不排水桩联合使用的组合型复合地基,既可以提高地基承载力,又可以加快土体固结,对处理饱和软黏土地基有很高的应用价值。基于双向渗流的轴对称固结计算模型,考虑中心及外围碎石桩的体积压缩、桩体施工的扰动效应,建立了组合碎石桩-不排水桩复合地基固结微分方程,采用解析法推导了附加应力随时间和深度变化下的组合桩复合地基固结解析解,包括碎石桩、桩间土的平均超静孔隙水压力解和复合地基整体平均固结度解。进行退化研究,并与已有解分析对比;验证了此解的正确性,且通过参数分析研究了复合地基的固结性状。结果表明:复合地基底部附加应力越小、碎石桩与不排水桩布置越密集,固结越快;碎石桩施工的扰动效应对复合地基影响大于不排水桩;忽略碎石桩体积压缩的影响会高估复合地基固结速率,且桩径比越小,误差越大;理论解预测的复合地基固结度与实测值拟合性较好。The composite foundation with combined stone columns and impervious piles can not only improve the bearing capacity of the foundation,but also accelerate the consolidation of soil,which has a strong application value in treating saturated soft clay foundation.Based on the calculation model of axisymmetric consolidation with bidirectional seepage,a consolidation differential equation of composite foundation reinforced by stone columns and impervious piles is established by considering the volume compression of central and peripheral stone columns and the disturbance effect of piles construction.The analytical solution of the combined composite foundation consolidation under the variation of additional stress with time and depth is derived by using the analytical method,including the solutions of average excess pore water pressure of stone columns and soil and the average consolidation degree of composite foundation.The correctness of the solution is verified by degradation study and comparison with existing solutions.Finally,a smaller additional stress at the bottom of the composite foundation,or a denser distribution of stone columns and impervious piles,will lead to a faster consolidation of the combined composite foundation.The disturbance effect of stone columns construction on composite foundation is greater than that of impervious piles.Ignoring the effect of the volume compression of stone columns will overestimate the consolidation rate of composite foundation;the smaller the radius ratio is,the larger the error will be.A good agreement can be observed between the predicted consolidation degree by the theoretical solution and the measured one.

关 键 词：复合地基 双向渗流 体积压缩 附加应力 解析解 

分 类 号：TU470[建筑科学—结构工程]