摘要
为了探究土岩双元基坑的破坏模式及判定标准,依托具体案例,采用PLAXIS 3D有限元数值模拟软件,利用强度折减法,得到下卧岩体稳定时不同上覆土层厚度的4种基坑破坏模式演变规律和不同下卧岩体的基坑破坏模式判定标准。利用条分法推导出圆弧、圆弧-平面、切面和滑切破坏模式整体稳定性统一解析解,针对切面和滑切破坏模式,得到不同下卧岩体发生破坏时的临界上覆土层厚度,推导出保持岩体切角稳定的最小支护作用力计算公式。结合多个基坑工程案例进行验证,结果表明:土岩双元基坑的破坏模式有别于土体基坑,应充分考虑岩体的强度和稳定性。下卧岩体稳定时,随上覆土层厚度增大,土岩双元基坑的破坏模式逐渐从圆弧破坏向圆弧-平面、切面和滑切破坏过渡转变,破坏模式判定标准及稳定性解析解具有合理性研究结果,可以为土岩双元基坑合理支护提供支持和参考。
In order to explore the failure mode and judgment criteria of soil-rock dual foundation pit,this paper relied on specific cases,adopted PLAXIS 3D finite element numerical simulation software and strength reduction method to obtain the evolution rules of four types of foundation pit failure modes for different overlying soil thickness and the criteria for determining foundation pit failure modes for different underlying rock mass when the rock mass was stable.A unified analytical solution for the overall stability of arc,arc-plane,tangent plane and slip shear failure modes was derived by using the strip division method.According to the failure modes of sectional-plane and slip-shear,calculated the critical overlying soil thickness of different underlying rock mass,and derived the calculation formula of minimum supporting force to keep the rock mass incisal angle stable.The results showed that the failure mode of soil-rock dual foundation pit was different from that of soil foundation pit,and the strength and stability of rock mass should be fully considered.When the underlying rock mass was stable,with the increase of the thickness of the overlying soil layer,the failure mode of the soil-rock dual foundation pit gradually changed from circular failure to circular plane failure,tangent failure and sliding shear failure.The criterion of failure mode and the analytical solution of stability were reasonable.The research results could provide support and reference for the rational support of soil-rock dual foundation pit.
作者
李连祥
韩志霄
张潇潇
陈家财
LI Lianxiang;HAN Zhixiao;ZHANG Xiaoxiao;CHEN Jiacai(Foundation Pit and Deep Foundation Engineering Research Center,Shandong University,Jinan 250061,Shandong,China;School of Civil Engineering and Hydraulic Engineering,Shandong University,Jinan 250061,Shandong,China;Qingdao Municipal Public Engineering Quality and Safety Supervision Station,Qingdao 266011,Shandong,China;The Fifth Engineering Co.Ltd.,China Railway First Inning Group,Baoji 721000,Shaanxi,China)
出处
《山东大学学报（工学版）》
CAS
CSCD
北大核心
2024年第3期70-80,共11页
Journal of Shandong University（Engineering Science）
关键词
土岩双元基坑
直立开挖
破坏模式
稳定性分析
解析解
soil rock dual foundation pit
vertical excavation
failure mode
stability analysis
analytical solution
