考虑排水板淤堵时空变化的多元复合地基固结性状研究  

Consolidation behaviors of multi-reinforcement composite ground considering time-and depth-dependent clogging effects of prefabricated vertical drains

作　　者：卢萌盟 白垚[1,2] 杨康 LU Mengmeng;BAI Yao;YANG Kang(School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou 221006;China State Key Laboratory of Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Xuzhou 221006,China)

机构地区：[1]中国矿业大学力学与土木工程学院,江苏徐州221116 [2]中国矿业大学深部岩土力学与地下工程国家重点实验室,江苏徐州221116

出　　处：《岩土工程学报》2023年第8期1564-1573,共10页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金项目(52178373,51878657);江苏省高校“青蓝工程”项目。

摘　　要：以塑料排水板联合水泥搅拌桩复合地基为研究对象,假定排水板的渗透系数随时间的指数函数与深度的线性函数同时衰减,考虑了排水板淤堵的时空变化效应;同时,考虑排水板涂抹作用、水泥搅拌桩的扰动效应以及土体径、竖向渗流,建立了该问题的多元复合地基固结解析模型,推导了该模型的固结控制方程及其解析解,并将解答退化到排水板淤堵效应仅随时间变化和仅随深度变化的工况。通过将本文解答与实际工程案例进行对比分析,验证了本文解答的正确性。最后,采用参数敏感性分析法对多元复合地基固结性状进行研究。研究结果表明:相对于恒井阻的情况,考虑排水板的淤堵效应时空变化的地基平均孔压的消散和固结将减慢,且减慢的趋势可看作单一因素减慢趋势的叠加;θ_(1)越小,θ_(2)和θ_(3)越大,多元复合地基固结越慢,当θ_(3)较大时,径向固结停止,地基最终只靠竖向渗流完成固结。Taking the composite ground improved by prefabricated vertical drains(PVDs)and cement mixing piles as the research object,an analytical model for the consolidation of multi-reinforcement composite foundation is established by considering the clogging effects of PVDs based on an assumption that their permeability coefficient decays simultaneously as an exponential function of time and a linear function of depth.Moreover,the following factors are also considered:the smearing effects of PVDs,the disturbance effects of cement mixing piles,and the radial and vertical seepages within the soil.The analytical solutions for the analytical model are subsequently deduced.After then,the solutions are degenerated to the cases with only the time-or depth-dependent well resistance.The correctness of the solutions is verified by comparing the predicted results with the measured data.Finally,the consolidation behaviors of the multi-reinforcement composite foundation are investigated through a series of the parametrical analysis.The results show the consolidation rate slows down when considering the time-and depth-dependent well resistance of PVDs by comparing that of the constant well resistance.Moreover,the reduction in the consolidation rate can be regarded as the sum of the influences of each single factor.The smaller the values of 1qand the larger the values of 2qand 3q,the slower the consolidation rate.When 3qincreases to a certain extent,the radial consolidation ceases,and the consolidation process will be completed only by the vertical flow at the later stage of consolidation.

关 键 词：多元复合地基 排水板 变井阻 固结 淤堵效应 

分 类 号：TU470[建筑科学—结构工程]