既有建筑物地下增层基坑开挖数值模拟分析

Numerical simulation analysis of foundation pit excavation in existing buildings

利用Plaxis建立二维有限元模型,对既有建筑物地下增层基坑开挖进行数值模拟分析,计算结果表明,基坑开挖及降水引起的中间区域既有桩基几乎无水平位移,边桩水平位移相对较大(mm数量级);基坑开挖引起工程桩隆起,基坑降水引起工程桩下沉。同时提出了有利于减少既有桩基变形的措施:适当增大围护、支撑刚度,工程桩设置联系杆(拉结杆)及基坑按需降水等,这一结论可为类似工程提供借鉴作用。

Using Plaxis to establish a two-dimensional finite element model to the existing buildings,underground excavation is simulated by layer analysis,the calculation results show that the foundation pit excavation and precipitation in the middle region of the existing pile almost no horizontal displacement,horizontal displacement of pile side is relatively large. At the same time is proposed to reduce the existing pile deformation measures: increasing pit,bracing stiffness,pile setting connection rod,and excavation according to precipitation. This conclusion can provide reference for similar engineering.