深基坑内钢支撑轴向压力变化规律研究  

Variation of axial force of steel struts in deep excavations

作　　者：曹雪山[1] 陆新宇 顾祎鸣 CAO Xue-shan;LU Xin-yu;GU Yi-ming(College of Civil Engineering and Transportation Engineering,Hohai University,Nanjing 210024,China;Shanghai Tunnel Engineering Co.,Ltd.,Shanghai 200032,China;Sinoroad Traffic Science&Technology Co.,Ltd.,Nanjing 210032,China)

机构地区：[1]河海大学道路与铁道研究所,江苏南京210024 [2]上海隧道工程有限公司,上海200032 [3]中路交科科技股份有限公司,江苏南京210032

出　　处：《岩土工程学报》2022年第11期1988-1997,共10页Chinese Journal of Geotechnical Engineering

基　　金：江苏高校优势学科建设工程资助项目(SYS19092);国家重点研发计划重点专项(2017YFC0404801,2017YFC0404804)。

摘　　要：钢支撑轴力实测数据离散、变化规律性不清是钢支撑设计的重要问题,严重影响着深基坑工程安全和工程经济合理性。以南京地铁某车站软土基坑工程为例,通过建立三维有限元模型,研究了钢支撑轴力变化规律。结合基坑开挖过程中的监测数据,提出了钢支撑轴力与围护墙体位移双元组合的方法,验证了模型合理性,同时揭示了深基坑开挖过程中围护墙位移和支撑轴力变化的相关性规律。然后研究了单道、双道预加轴力对钢支撑轴力、墙体位移和弯矩的影响,提出了采用预加轴力技术控制变形的基本要求,研究了支撑架设条件的影响,阐明了支撑轴力实测值离散的原因和超挖对基坑安全的重要影响,进而明确了悬挂架设钢支撑的研究意义。研究成果对厚层软土深基坑的变形控制技术发展提供了新方向。The discrete data and unclear variation trend of axial force of steel structs are the important design problems, which seriously affect the safety and economic rationality of deep excavations. A three-dimensional finite element model for a deep soft excavation in Nanjing Metro station is established to study the variation of axial force of steel struts. Based on the monitoring data in the process of excavation, the dual-combination method for the axial forces of steel struts and wall deflection is put forward to validate the rationality of the model and parameters. The correlation between the wall deflection and the axial force of steel struts during is excavation revealed. Then, the influences of single-and double-axial preloading on the axial forces of steel structs, wall deflection and moment are studied to propose the basic requirements of using the preloading axial force technology to control deformation. The influences of struct erection conditions are studied to expound the reason of the discrete measured values of axial force of steel struts and the important influences of over-excavation on the safety of engineering, and to reveal the research significance of hanging steel struct erection. The research results may provide a new direction for the development of deformation control technology of deep excavations in thick soft soils.

关 键 词：深基坑 钢支撑 轴力变化 预加轴力 支撑架设条件 

分 类 号：TU476[建筑科学—结构工程]