多道撑式深基坑垮塌事故连续破坏机理研究  

Study on three-dimensional progressive collapse mechanism of excavation retained by multi-braced diaphragm wall

作　　者：程雪松[1,2] 裴昊田 衣凡 赵璟璋 俞丹瑶 刘晓敏 贾建伟 焦莹 Cheng Xuesong;Pei Haotian;Yi Fan;Zhao Jingzhang;Yu Danyao;Liu Xiaomin;Jia Jianwei;Jiao Ying(Key Laboratory of Coastal Civil Structure and Safety of Ministry of Education,Tianjin University,Tianjin 300072,China;School of Civil Engineering,Tianjin University,Tianjin 300072,China;China Construction Sixth Engineering Bureau Corp.,Ltd.,Tianjin 300457,China)

机构地区：[1]天津大学滨海土木工程结构与安全教育部重点实验室,天津300072 [2]天津大学建筑工程学院,天津300072 [3]中国建筑第六工程局有限公司,天津300457

出　　处：《土木工程学报》2024年第3期102-109,共8页China Civil Engineering Journal

基　　金：国家自然科学基金(52178343);中建股份科技研发计划资助(CSCEC-2020-Z-46)。

摘　　要：随着城市地铁建设不断发展,多道撑式深基坑应用日益广泛,然而目前对于内撑式深基坑局部破坏引发连续破坏在空间上的传递规律仍缺乏系统研究。文章依托新加坡地铁Nicoll Highway基坑事故,建立三维有限差分模型,提出内支撑荷载传递百分比S1,i和荷载增量承担百分比S2,i两种支撑荷载(轴力)传递评价指标。对比分析了单位厚度平面应变模型与三维模型的模拟结果,探究了不同初始破坏支撑数量在不同位置发生初始破坏所引发的荷载重分布规律,同时还研究了围护结构体系刚度和强度对于连续破坏发展的影响。结果表明,三维模型可以避免平面应变模型传力路径单一的局限性,更好地反映出连续破坏在三维空间中的传递现象;初始破坏支撑所释放的荷载主要作用在紧邻层支撑;当失效荷载存在向下的传递路径时,紧邻初始破坏的上层和同层支撑承担的荷载增量明显减少;底层支撑的安全系数提高会减缓连续破坏在水平方向的发展;支撑刚度越大,在初始破坏后所承担的荷载增量越多;当墙体间无有效连接时,支撑连续破坏沿竖直方向发展的趋势更加显著。At present,there is still a lack of systematic research on the three-dimensional transmission law of progressive collapse caused by local failure of braced deep excavation.Based on the Nicoll Highway accident in Singapore,a three-dimensional finite difference model was established and two evaluation indexes for the axial force transfer of struts,namely the percentage of self-load transfer of struts S1,i and the percentage of incremental load bearing S2,i,were proposed.The calculation results of the plane-strain model and three-dimensional model were compared and analyzed,and the load redistribution law caused by the failure of struts with different initial failure quantities at different positions was explored.The influence of stiffness and strength of struts on progressive collapse was also studied.The three-dimensional model can avoid the limitation of single force transmission path of the plane-strain model and better reflect the transmission phenomenon of progressive collapse in three-dimensional space.The load released by the initial failure struts mainly acts on the adjacent struts.When the failure load has a downward transfer path,the load increment of the upper layer and horizontal struts adjacent to the initial failure is significantly reduced.The improvement on the safety factor of bottom struts can retard the development of progressive failure in the horizontal direction.The larger the struts stiffness,the more load increment will be borne after the initial failure.When there is no effective connection between the diaphragm walls,the trend of progressive collapse of struts along the vertical direction is more significant.

关 键 词：深基坑 内支撑 有限差分模型 连续破坏 荷载传递 

分 类 号：TU473[建筑科学—结构工程]