基于Plaixs2D的非对称开挖支撑刚度对基坑支护结构的变形影响

Influence of bracing stiffness of asymmetric excavation on deformation of foundation pit retaining structure based on Plaixs2D

基于南昌地铁3号线艾溪湖地铁隧道工程案例,结合非极限状态下的土压力理论和基坑支护结构综合刚度理论,应用Plaxis有限元软件对照实测数据研究了非对称基坑开挖过程中单水平横向支撑的基坑支护结构变形特性和支撑刚度的不同对基坑支护结构变形特性的影响。结果表明非对称基坑开挖过程中现有的支护结构的设计存在安全冗余,值得进一步做经济效益上的优化;随着水平横向支撑刚度的增大,支护结构的最大变形也会减小但减小速度会放缓,且深侧支护结构会对浅侧支护结构产生推回位移,由此如何安全经济地设计水平横向支撑也十分重要。

Based on the case of Aixihu subway tunnel in Nanchang Metro Line 3,combined with the earth pressure theory in non-limit state and the comprehensive stiffness theory of foundation pit supporting structure,the influence of deformation characteristics and bracing stiffness of foundation pit retaining structure with single horizontal lateral support on the deformation characteristics of foundation pit retaining structure in the process of asymmetric foundation pit excavation is studied using Plaxis method.The results show that there is safety redundancy in the design of the existing supporting structure in the process of asymmetric foundation pit excavation,which is worthy of further optimization in economic benefits;with the increase of horizontal lateral bracing stiffness,the maximum deformation of the supporting structure will also decrease,but the speed of reduction will slow down,and the deep side supporting structure will produce push-back displacement to the shallow side supporting structure,so how to design the horizontal lateral support safely and economically is also very important.