不同褥垫层厚度下大直径CFG桩复合地基桩土应力比试验研究  

Experimental Study on Pile-Soil Stress Ratio of Large Diameter CFG Pile Composite Foundation under Different Cushion Thickness

作　　者：李扬波 容耀 任志勇 吴波 刘聪 梁华 LI Yangbo;RONG Yao;REN Zhiyong;WU Bo;LIU Cong;LIANG Hua(School of Civil and Architectural Engineering,East China University of Technology,Nanchang 330013,China;Engineering Research Center for Geological Environment and Underground Space of Jiangxi Province,East China University of Technology,Nanchang 330013,China;Hunan Jiao Jian Group Co.,Ltd.,Changsha 410013,China;Jiangxi Provincial Communication Investment Group Co.,Ltd.,Nanchang 330003,China)

机构地区：[1]东华理工大学土木与建筑工程学院,江西南昌330013 [2]东华理工大学江西省地质环境与地下空间工程研究中心,江西南昌330013 [3]湖南教建集团有限公司,湖南长沙410013 [4]江西省交通投资集团有限公司,江西南昌330003

出　　处：《东华理工大学学报（自然科学版）》2023年第2期179-185,共7页Journal of East China University of Technology(Natural Science)

基　　金：江西省地质环境与地下空间工程研究中心开放基金项目(JXDHJJ2021-007);江西省教育厅科学技术研究项目(GJJ210705);国家自然科学基金项目(52168055);江西省自然科学基金项目(20212ACB204001);江西省“双千计划”创新领军人才项目(jxsq2020101001)。

摘　　要：褥垫层厚度是调整复合地基工作状态的主要参数。基于相似关系开展了室内模型试验,分析了砂土地基中不同褥垫层厚度下大直径CFG桩复合地基桩土应力比的变化规律。试验结果表明:当褥垫层厚度一定时,桩土应力比随荷载增加先快速上升后趋于稳定;当荷载一定时,桩土应力比随褥垫层厚度增大而逐渐减小;在加载初期,桩间土发挥主要承载作用,随着荷载增加,桩体逐渐发挥承载能力;褥垫层具有应力扩散作用,过薄不利于桩间土承载能力的发挥,过厚不利于桩体承载能力的发挥;当桩土应力比为5.4~11.2,砂土地基的褥垫层厚度与桩径比合理取值范围为0.37~0.74,能够充分发挥桩土共同承载能力。基于试验结果,提出能合理反映砂土地基中褥垫层厚度对桩土应力比影响规律的数学模型,以期为类似工程设计施工提供借鉴。The cushion thickness is an important parameter for adjusting the working state of the composite foundation.Based on the similarity relationship,the indoor model test is carried out to analyze the variation law of pile-soil stress ratio of large-diameter CFG pile composite foundation under different cushion thickness in sand foundation.The experimental results indicate that,with a constant thickness of the bedding layer,the stress ratio of the pile-soil increases rapidly with an increase in load and then tends to stabilize.When the load is constant,the pile-soil stress gradually decreases with the enhanced cushion thickness.The inter-pile soil plays an important role in the initial phase of loading,and the bearing capacity of the pile develops gradually.The cushion has a stress diffusion effect.Too thin thickness of the cushion is not conducive to the bearing capacity of soil between piles,and too thick thickness is not conducive to the bearing capacity of piles.When the pile soil stress ratio is 5.4~11.2,the optimum range of the cushion layer thickness to pile diameter ratio of the sandy foundation is 0.37~0.74.This enables the joint bearing capacity of the pile and soil to be fully utilized.Finally,based on the test results,a mathematical model that can reasonably reflect the influence of cushion thickness on pile-soil stress ratio in sand foundation is proposed to provide reference for similar engineering design and construction.

关 键 词：大直径CFG桩 模型试验 褥垫层 桩土应力比 

分 类 号：TU472.99[建筑科学—结构工程]