摘要
研究目的:复杂地层大直径地铁盾构井基坑施工过程中,土体变形受到诸多因素影响,具有显著的地区、形状等差异性,有必要基于施工前的数值模拟与施工中的监测数据,进行施工土体变形规律研究。研究结论:(1)基于假设条件与工程简化模型,对于本工程初始方案的12个典型工况进行了数值模拟,基坑长边、短边方向上12个施工步可能出现的最大竖向变形分别为17.21 mm、50.81 mm,应在施工过程进行实时监测;(2)施工过程中,监测竖向变形最大值为28.01 mm,已接近工程允许值30.00 mm,建议适当延长监测周期;(3)对于本工程而言,监测区段的竖向变形在空间上与理论曲线较为接近,并随盾构井开挖深度增加而增大,同时因为监测点布置空间距离较小等因素影响,监测数据在空间上未能形成空间上的完整沉降槽;(4)数值模拟与工程实际存在差异,而施工监测由于多类条件限制,数据通常不完备,施工中二者应相互补充;(5)本研究成果可为类似地铁基坑工程的土体竖向变形规律研究提供参考。
Research purposes:The soil deformation in the metro foundation pit construction in composite strata is affected by many factors and has significant differences considering regional and shape factors.It is necessary to investigate the deformation mechanism based on the numerical simulation before construction and on the monitoring data during construction.Research conclusions:(1)Based on the simplified engineering model and assumptions,12 scenarios of the initial scheme are numerically simulated.The maximum vertical deformation of the 12 construction steps in the direction of long side and short side of the foundation pit is 17.21 mm and 50.81 mm respectively.The deformation should be real-time monitored in the construction process.(2)The monitored maximum vertical deformation is 28.01 mm,which is close to the allowable value of 30.00 mm.The monitoring period in the engineering is recommended to extend.(3)The vertical deformation of the monitoring section is relatively close to the theoretical curve in space,and increases with the increase of the excavation depth of the shield shaft.The settlement trough in space is uncompleted because of the small spatial distance of the monitoring points,and the effects of the other factors.(4)There are differences between the numerical simulation and the monitoring data.The monitoring data in construction are usually incomplete due to lots of factors,so the two should complement each other during construction.(5)The research results can provide reference for the similar foundation pit projects in metro construction.
作者
李炜明
朱义
王慕鸿
连杰
刘旭强
吴政
LI Weiming;ZHU Yi;WANG Muhong;LIAN Jie;LIU Xuqiang;WU Zheng(Wuhan Polytechnic University,Wuhan,Hubei 430023,China;China Railway 22nd Bureau Group Rail Engineering Corporation Limited,Beijing 100040,China)
出处
《铁道工程学报》
EI
CSCD
北大核心
2023年第5期102-109,共8页
Journal of Railway Engineering Society
基金
武汉轻工大学2021年度校立科研项目(2021Y45)
关键词
地铁施工
土体变形
基坑监测
数值模拟
规律分析
metro construction
soil deformation
foundation pit monitoring
numerical simulation
mechanism analysis
