软弱地层基坑开挖支护方案比选研究  

Study on Comparison and Selection of Foundation Pit Excavation and Support Schemes in Soft Ground

作　　者：贺旭 HE Xu(China Railway Urban Construction Group Co.Ltd.,Changsha Hunan 410208,China)

机构地区：[1]中铁城建集团有限公司,湖南长沙410208

出　　处：《铁道建筑技术》2023年第5期100-104,125,共6页Railway Construction Technology

基　　金：中铁城建集团有限公司科技研究开发计划项目(CJKY-NC-2022-009)。

摘　　要：针对软弱地层基坑开挖稳定性问题,结合实际软弱地基基坑开挖实例,以不同开挖步骤为基础,分析了软弱地层基坑在开挖过程支护结构内力变化,并依据软弱地层土体性质对其稳定性进行校核。通过对不同支护方案下结构内力和安全系数对比分析,明确了软弱地层基坑支护最佳支护方案。结果表明:软弱地层基坑开挖可分为“浅部开挖和支护”“深部开挖和支护”“拆除支护”三个步骤进行,“PC工法桩+钢筋混凝土支撑”的方式可以有效抑制软弱地层边坡变形,增加基坑稳定性。本工程中基坑开挖的深度影响范围约为5~10 m,且基坑边坡土体最大位移出现在基坑顶部;竖向支护结构的弯矩和剪力在基坑开挖底部附近会出现极值,并呈现正负交替现象。In view of the stability of foundation pit excavation in soft stratum,this paper combines with the actual case of foundation pit excavation in soft stratum to analyze the internal force change of support structure in soft stratum foundation pit excavation process based on different excavation steps,and checks its stability according to the nature of soft stratum soil.Through the comparative analysis of structural internal force and safety factor under different support schemes,the best support scheme of foundation pit support in soft stratum is determined.The results show that the excavation of foundation pit in soft stratum can be divided into three steps:“shallow-excavation and support”,“deep excavation and support”,“support demolition”.The“PC construction pile+reinforced concrete support”method can effectively restrain the deformation of soft stratum slope and increase the stability of foundation pit.In this project,the influence range of the depth of the foundation pit excavation is about 5~10 m,and the maximum displacement of the foundation pit slope soil appears at the top of the foundation pit.The bending moment and shear force of vertical support structure will appear extreme value near the bottom of foundation pit excavation,and show positive and negative alternation.

关 键 词：软弱地层 支护结构 方案比选 内力包络图 稳定性 

分 类 号：TU753[建筑科学—建筑技术科学]