修正等应变假定下刚性桩复合地基固结特性分析

doi:10.16285/j.rsm.2019.1551

岩土力学 ›› 2020, Vol. 41 ›› Issue (3): 813-822.doi: 10.16285/j.rsm.2019.1551

修正等应变假定下刚性桩复合地基固结特性分析

郎瑞卿¹，杨爱武^{1, 2}，闫澍旺³

1. 天津城建大学天津市软土特性与工程环境重点实验室，天津 300384；2. 东华大学环境科学与工程学院，上海 201620； 3. 天津城建大学土木工程学院，天津 300384

收稿日期:2019-09-09 修回日期:2020-01-20 出版日期:2020-03-11 发布日期:2020-05-25
通讯作者: 杨爱武，男，1971年生，博士，教授，主要从事软黏土力学性质及土体微观结构的研究工作。E-mail: tulilab@163.com E-mail:tculrq@163.com
作者简介:郎瑞卿，男，1991年生，博士，讲师，主要从事地基处理等工作
基金资助:
天津市自然科学基金项目（No.19JCQNJC06900，No.19JCZDJC39700）；国家自然科学基金项目（No.51978440）。

Analysis of consolidation properties of rigid pile composite foundation based on modified equal strain assumption

LANG Rui-qing¹, YANG Ai-wu^{1, 2}, YAN Shu-wang³

1. Key Laboratory of Soft Soil Engineering Character and Engineering Environment of Tianjin, Tianjin Chengjian University, Tianjin 300384, China; 2. College of Environmental Science and Engineering, Donghua University, Shanghai 201620, China; 3. School of Civil Engineering, Tianjin Chengjian University, Tianjin 300384, China

Received:2019-09-09 Revised:2020-01-20 Online:2020-03-11 Published:2020-05-25
Supported by:
This work was supported by the Natural Science Foundation of Tianjin, China(19JCQNJC06900, 19JCZDJC39700) and the National Natural Science Foundation of China(51978440).

摘要/Abstract

摘要： 刚性桩复合地基固结特性是影响工程进度的重要因素。为研究外荷载作用下刚性桩复合地基固结特性，结合刚性桩和桩间土应力?应变特点对等应变假定进行修正。在此基础之上，考虑涂抹效应、桩间土和下卧层土体固结特性的影响，推导得到桩间土和下卧层土体固结微分方程。基于双层地基固结理论，考虑单级匀速施加荷载和附加应力沿深度变化等边界条件，推导得到其固结度解析解。最后，利用数值模拟方法对解析解进行验证，并对影响刚性桩复合地基固结特性的因素进行分析。结果表明：理论计算与数值模拟结果较为吻合；刚性桩复合地基固结速率受到贯入比影响较大，当贯入比较小时，与天然地基相比，其固结速率较小，贯入比较大且桩端阻力系数较小时，复合地基固结速率大于天然地基；随着贯入比、桩?土相对刚度和垫层?土体相对刚度的增大，复合地基整体固结速率加快；随着置换率的增大，复合地基整体固结速率降低。

关键词: 刚性桩复合地基, 修正等应变假定, 固结特性, 变附加应力, 下卧层

Abstract: The consolidation characteristics of rigid pile composite foundation is a key factor affecting the progress of the project. To study the consolidation properties of rigid pile composite foundation under external load, the equal strain assumption was modified based on stress-strain characteristics of rigid pile and its surrounding soil. Considering the smearing effect, the consolidation behavior of surrounding soil and underlying stratum, the governing equations for the average excess pore water pressure within the surrounding soil and the underlying soil were developed. According to the boundary conditions of a time-dependent loading and additional stress varied with time and depth, the analytic solutions of consolidation degree were derived based on the consolidation theory of double-layered ground. The proposed method was validated by numerical simulation method. The factors that affect consolidation properties were systematically analyzed. It shows that the analytical solutions have great agreement with the numerical simulation results. The average consolidation rate strongly depends on the penetration ratio of the rigid pile. The average consolidation rate is slower than that of natural ground when the ratio is small. The average consolidation rate of rigid pile composite foundation with a greater penetration ratio and a smaller pile end resistance coefficient is faster than that of natural ground. With the increase of pile penetration ratio, the ratio of the constrained modulus of the pile to that of the soil and the ratio of the constrained modulus of the cushion layer to that of the soil, the overall consolidation rate of the composite foundation is accelerated. With the increase of the replacement rate, the overall consolidation rate of the composite foundation decreases.

Key words: rigid pile composite foundation, modified equal strain assumption, consolidation characteristic, stress varied with depth, underlying stratum

中图分类号:

TU473

郎瑞卿, 杨爱武, 闫澍旺, . 修正等应变假定下刚性桩复合地基固结特性分析[J]. 岩土力学, 2020, 41(3): 813-822.

LANG Rui-qing, YANG Ai-wu, YAN Shu-wang, . Analysis of consolidation properties of rigid pile composite foundation based on modified equal strain assumption[J]. Rock and Soil Mechanics, 2020, 41(3): 813-822.

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修正等应变假定下刚性桩复合地基固结特性分析

Analysis of consolidation properties of rigid pile composite foundation based on modified equal strain assumption

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