摘要
坑中坑式基坑在基坑底部进行二次开挖,其隆起破坏机理比普通单一基坑要复杂.采用强度折减有限元分析法研究坑中坑式基坑的抗隆起稳定性.研究了内外坑间平台宽度,内坑宽度和深度,内外坑挡墙的插入深度,软土层不排水抗剪强度等归一化参数对坑中坑式基坑抗隆起破坏模式及抗隆起稳定安全系数的影响.坑中坑式基坑的抗隆起破坏模式可分为三种内外坑整体隆起破坏(M1),内外坑整体隆起破坏和外坑独立隆起破坏同时发生(M2),外坑独立隆起破坏(M3).确定基坑破坏模式在M1,M2以及M3之间转化时,各个参数的临界值.增大内外坑间平台宽度,内外坑挡墙的插入深度以及软土层的不排水抗剪强度,会提高坑中坑式基坑的抗隆起稳定安全系数.增大内坑的宽度和深度则会降低坑中坑式基坑的抗隆起稳定安全系数.
For pit-in-pit excavated in the bottom of outer pit,the failure mechanism of basal heave is more complicated than normal pit.Finite element method based on the reduced shear strength technique is used to evaluate the basal heave stability of pit-in-pit excavations.The influence of spacing between inner and outer pit,width and depth of inner pit,depth of inner and outer wall insertion,undrained shear strength of clay on the failure modes and factor of safety is analyzed.In conclusion,there are three kinds of failure modes of pit-in-pit excavation:entire f ailure of inner and outer pit(M1),entire failure of inner and outer pit(M2),failure of outer braced pit(M3).The critical value of parameters is determined for the change of different failure modes.The basal stability of pit-in-pit excavations will increase with the spacing between inner and outer pit,The depth of inner and outer wall insertion,and the undrained shear strength of clay.Nevertheless it will decrease with the increase of width and depth of inner pit.
作者
朱兴云
繆广吉
周宏伟
林上顺
李惠霞
ZHU Xingyun;MIAO Guangji;ZHOU Hongwei;LIN Shangshun;LI Huixia(China Railway Second Bureau Fifth Engineering Co.,Ltd.,Chengdu 610000,China;College of Civil Engineering,Fuzhou University,Fuzhou 350116,China;China Railway Second Bureau Third Engineering Co.,Ltd.,Chengdu 610000,China;School of Civil Engineering,Fujian University of Technology,Fuzhou 350118,China)
出处
《西安建筑科技大学学报（自然科学版）》
北大核心
2020年第4期505-513,共9页
Journal of Xi'an University of Architecture & Technology(Natural Science Edition)
基金
国家自然科学基金资助项目(41572253)。
关键词
坑中坑
抗隆起稳定
强度折减
有限元
pit-in-pit
basal heave stability
shear strength reduction technique
finite element method
