深基坑开挖坑底隆起影响因素有限元分析

Finite Element Analysis of Influence Factors for Basal Heave of Deep Foundation Excavation

深基坑工程中由于土体开挖卸荷,导致基坑坑底隆起,其隆起量的大小直接关系到基坑安全和稳定,已越来越受到重视。系统地研究基坑坑底隆起的影响因素并对其进行有限元分析尚不多见。利用有限元软件ABAQUS建立有限元模型,研究坑底工程桩、坑底被动区加固、地下连续墙插入深度和坑底软土层厚度等对坑底隆起变形的影响,并探讨各隆起变形控制措施的控制效果。最后通过南京某隧道基坑的实测数据,验证了坑底设置工程桩对坑底隆起的控制效果。

Due to soil unloading in deep excavation,causing basal heave in the bottom pit,and the amount of basal heave is directly related to the security and stability of foundation pits,which has been receiving increasing attention. Systematic study and finite element analysis of influence factors for basal heave of deep foundation pits is still rare. A finite element model is established by means of ABAQUS to study the effect of some influence factors on basal heave in the bottom pit and discuss the effect of various measures to control the deformation of basal heave. These factors include foundation piles below excavation base, soil improvement below excavation base, wall penetration depth and thickness of soft clay below excavation. Finally,the measured data of a tunnel excavation in Nanjing reveals the effect of the measure of constructing foundation piles below excavation base to control the deformation of basal heave.