不同嵌岩深度圆形地连墙的受力及变形特性数值分析  

Numerical Analysis on Mechanical Behavior and Deformation Characteristics of Circular Diaphragm Wall with Different Rock-socketed Lengths

作　　者：李宁[1,2] 张茂建 许建聪[2] 张慧莉 汪波 LI Ning;ZHANG Mao-jian;XU Jian-cong;ZHANG Hui-li;WANG Bo(School of Environment and Architecture,University of Shanghai for Science and Technology,Shanghai 200093,China;Key Laboratory of Geotechnical and Underground Engineering of Ministry of Education,Tongji University,Shanghai 200092,China)

机构地区：[1]上海理工大学环境与建筑学院,上海200093 [2]同济大学岩土及地下工程教育部重点实验室,上海200092

出　　处：《公路交通科技》2024年第10期149-162,共14页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(40872179,U1765110);上海市自然科学基金项目(16ZR1423300)。

摘　　要：对于土岩结合地质基坑圆形围护结构,国内外学者多数是基于嵌岩深度相同情况下对圆形地连墙的变形或力学特性进行研究,而根据基坑地质具体情况采用不同嵌岩深度的地连墙则可缩短施工周期,节约施工成本。清晰认识墙体在基坑开挖过程中的受力及变形特性对于预防潜在的安全风险至关重要。结合某竖井工程基坑土岩结合的地质特点,通过有限元计算软件建立了不同嵌岩深度圆形地连墙三维模型,分析了基坑的最大坑底回弹位移及圆形地连墙的水平、竖直位移与轴向弯矩和剪力变化规律。结果表明:基坑坑底回弹整体呈“N”形变化,且基坑软土部分开挖出现的坑底回弹要远大于岩层部分的开挖;墙体嵌入深度小于1/2基坑开挖深度,墙体水平变形呈“弓”形变化;墙体嵌入深度为50%~100%基坑开挖深度时,其水平变形呈“悬臂”形变化;墙体嵌入深度不小于基坑开挖深度,墙体水平变形呈“W”形变化,并且地连墙的竖向变形会在整个基坑开挖过程中呈现先上升后下降的变化规律;地连墙的轴向弯矩及剪力最大值均出现在土岩交界位置处,并且其最大值会随地连墙嵌岩深度的增加而增大。For the circular retaining structure of soil-rock combined geological foundation pit,most of scholars at home and abroad study the deformation or mechanical characteristics of circular diaphragm wall based on the same rock-socketed length;however,adopting diaphragm walls with various rock-socketed lengths tailored to the specific pit geological conditions can reduce the construction period and lower construction costs.Furthermore,a clear understanding of wall’s force and deformation characteristics during the excavation process is essential for preventing potential safety hazards.Considering the soil-rock interface geological features of vertical shaft engineering pit,the 3D model of circular diaphragm wall with different rock-socketed lengths was constructed by using finite element analysis software.The analysis focused on the maximum rebound displacement at pit bottom and the patterns of horizontal and vertical displacements,as well as the variations in axial bending moments and shear forces of circular diaphragm walls.The result indicates that the overall rebound of pit bottom follows an N-shaped pattern.The rebound at foundation pit bottom in soft soil is much larger than that in rock stratum.When the rock-socketed length is less than half of the excavation depth,the wall’s horizontal deformation exhibits an arch-shaped pattern.When the rock-socketed length is between 50%and 100%of excavation depth,the horizontal deformation follows a cantilever-shaped pattern.When the rock-socketed length is not less than the excavation depth,the horizontal deformation displays a w-shaped pattern;and the vertical deformation of diaphragm wall shows the initial increase followed by a decrease throughout the excavation process.The maximum axial bending moments and shear forces of diaphragm wall are located at the soil-rock interface;and these values increase with the increase of rock-socketed length.

关 键 词：隧道工程 内力及变形 数值模拟 复杂地层 不同嵌岩深度 圆形地连墙 

分 类 号：U455.8[建筑科学—桥梁与隧道工程]