单 位：
南京林业大学土木工程学院;江苏建科工程咨询有限公司
关键词：
地铁车站;基坑开挖;地表沉降;支撑优化;基坑支护体系
摘 要：
为揭示地铁车站基坑开挖变形规律及探究支撑优化,以南京某车站西区标准段基坑工程为背景,将开挖阶段现场实测位移与数值模拟进行对比,验证数值模拟方法正确性,并通过数值模拟分析首道支撑类别、支撑刚度,以及首末道支撑位置、支撑预加轴力对基坑变形及受力的影响,对钢支撑体系进一步优化,以期为今后类似工程提供借鉴。结果表明:随基坑开挖深度的增加,墙体水平位移整体逐渐增大,且最大位移位置逐渐下移,地表沉降也逐渐增大,且最大沉降位置距坑壁越来越远。将首道支撑由钢筋混凝土支撑替换为钢支撑可行,替换后位移量仍远小于报警值;适当增加刚度有一定优化作用,但刚度过大达到一定限值后,优化作用不明显,刚度取值应该在1～2倍。首道支撑架设位置下移对基坑变形受力影响较大,可考虑略微上移首道支撑位置,末道支撑假设位置移动影响很小,末道支撑位置可不做改变。增大预加轴力有利于减小基坑变形,钢支撑施加预加轴力的合理范围宜为设计轴力的70%～90%。
译 名：
Deformation law and support optimization of narrow and long foundation pit excavation
作 者：
TAO Yong;YANG Ping;JIA Hongzheng;QIN Hui;College of Civil Engineering,Nanjing Forestry University;Jiangsu Jianke Engineering Consulting Co.Ltd.;
关键词：
subway station;;foundation pit excavation;;surface settlement;;support optimization;;foundation pit support system
摘 要：
In order to reveal the deformation law of foundation pit excavation of subway station and explore support optimization,the foundation pit project in a standard section of a subway station in Nanjing is taken as the background,the field measured displacement data in the excavation stage are compared with the numerical simulation results,and the correctness of the numerical simulation method is verified by comparison.Through numerical simulation,the influence of the first support type,support stiffness,first and last support position and pre-axial force on the deformation and stress of the foundation pit is analyzed,and the steel support system of the foundation pit is further optimized,so as to provide reference for similar underground foundation pit projects in the future.The results show that,with the increase of excavation depth,the horizontal displacement of retaining wall increases gradually,and the maximum displacement position of retaining wall gradually moves down.The surface settlement also increases gradually,and the maximum settlement position is farther and farther away from the pit wall.It is feasible to replace the first support with a reinforced concrete support as a steel support,and the displacement after the replacement is still far less than the alarm value.Increasing the stiffness appropriately has a certain optimization effect,but when the stiffness reaches a certain value,the optimization effect is not obvious and the stiffness should be between one and two times.The downward movement of the first support erection position has a great influence on the deformation of the foundation pit,for this project,the first support position can be slightly moved up.The assumed position of the last support has little influence on the deformation and stress of the foundation pit,and the position of the last support can not be changed.Increasing the pre axial force can reduce the deformation of foundation pit,and the reasonable range for applying the pre-axial force to the steel support is preferably 70% to 90% of the designed axial force.
