软黏土地区深大基坑工程桩-连续墙体系空间变形效应  

Spatial deformation effect of pile-diaphragm wall system in deep and large foundation pit in soft clay area

作　　者：盛兴旺[1] 林超 郑纬奇 尹逊一 孙焕重 杨峰[1] SHENG Xingwang;LIN Chao;ZHENG Weiqi;YIN Xunyi;SUN Huanzhong;YANG Feng(School of Civil Engineering,Central South University,Changsha 410075,China;Hunan Tieyuan Civil Engineering Testing Co.,Ltd.,Changsha 410075,China;China Railway 14th Bureau Second Engineering Co.,Ltd.,Tai’an 271000,China)

机构地区：[1]中南大学土木工程学院,湖南长沙410075 [2]湖南铁院土木工程检测有限公司,湖南长沙410075 [3]中铁十四局集团第二工程有限公司,山东泰安271000

出　　处：《铁道科学与工程学报》2024年第2期591-601,共11页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(52078488);湖南铁院土木工程检测有限公司开放基金资助项目(HNTY2022K08)。

摘　　要：土体开挖过程中深大基坑存在明显的空间变形效应,对其主体结构力学行为产生影响。以新建苏州南站枢纽深大基坑为工程背景,考虑地连墙厚度及工程桩的影响,基于ABAQUS建立三维空间有限元模型,采用修正剑桥模型考虑软黏土的应变硬化特征,从地连墙侧向位移、墙后地表沉降、工程桩和坑底土体隆起3个方面,研究软黏土地区深大基坑工程桩-连续墙体系的变形特征及空间效应。研究结果表明:深大基坑地连墙的侧向位移和地表沉降均呈现明显的角部效应,基坑A区(地连墙厚度1 m、桩径1 m)地连墙侧向位移角部效应的影响范围为1.05~1.71倍开挖深度,基坑B区(地连墙厚度0.8 m、桩径1.5 m)地连墙侧向位移角部效应的影响范围为0.91~1.48倍开挖深度;基坑A区、B区地表沉降角部效应的影响范围分别为1.24~2.10和1.77~2.47倍开挖深度;深大基坑空间变形角部效应与工程桩桩径及地连墙厚度有关,并且对基坑长边的影响效果大于短边。工程桩可有效增大基坑开挖面以下土体的刚度,减小地连墙的侧向位移;增大地连墙厚度可有效降低基坑的整体变形。基坑工程桩与坑底土体隆起总体呈现中间大、周边小的特征,工程桩周边土体受其约束,隆起较小;在一定范围内,工程桩对土体隆起抑制作用与其桩径呈正相关,与其桩间距呈负相关。软黏土地区深大基坑设计计算中需关注工程桩-连续墙结构体系的空间变形效应。Significant spatial deformation effects are observed in deep and large foundation pits during soil excavation,which impacts the primary structure’s mechanical behavior.The deep and large foundation pit of the newly-built Suzhou South Railway Station was used as the engineering background,and the influences of the thickness of the diaphragm wall and the engineering piles were considered to establish a three-dimensional space finite element model based on ABAQUS.The modified Cam-clay model was used to consider the influence of the strain hardening characteristics of soft clay.This paper studied the deformation characteristics and spatial effects of the pile-diaphragm wall system in a deep and large foundation pit located in a soft clay area from three aspects:lateral displacement of the diaphragm wall,ground surface settlement behind the wall,and engineering piles and soil uplift at the bottom of the pit.The research results indicate that the lateral displacement of the diaphragm wall and the surface settlement behind the diaphragm wall in a deep and large foundation pit exhibit significant corner effects.For area A of the foundation pit(with a wall thickness of 1 meter and pile diameter of 1 meter),the influence range of the corner effect of the lateral displacement of the wall is 1.05 to 1.71 times the excavation depth.For area B of the foundation pit(with a wall thickness of 0.8 meters and pile diameter of 1.5 meters),the influence range of the corner effect of the lateral displacement of the wall is 0.91 to 1.48 times the excavation depth.The influence range of the corner effect on surface settlement for areas A and B of the foundation pit are 1.24~2.10 and 1.77~2.47 times the excavation depth,respectively.The spatial deformation corner effect of the deep foundation pit is related to the pile diameter and wall thickness,and has a greater effect on the long side of the pit than on the short side.The engineering piles effectively enhance the stiffness of the soil beneath the excavation surface,reducing the late

关 键 词：深大基坑 软黏土地区 有限元 修正剑桥模型 空间变形效应 

分 类 号：U231.3[交通运输工程—道路与铁道工程]