深基坑桩锚支护结构位移分析及数值模拟

Displacement Analysis and Numerical Simulation of Pile-anchor Retaining Structure in Deep Foundation Pit

基坑开挖会引起周边既有建筑和道路的沉降和位移。为了研究基坑开挖过程中,土体卸载对周边既有建筑的影响规律,以安徽璀璨明珠商场深基坑工程为研究对象,对桩锚支护结构在深基坑中的应用进行研究。通过理论分析、现场实测和三维快速拉格朗日方法(FLAC_(3D))数值模拟对支护结构进行综合分析,重点对比了在基坑开挖过程中支护结构及周边环境的位移实测数据和数值模拟结果的偏差,结果表明:运用FLAC_(3D)软件进行数值模拟,模型结果总体上与现场实测数据具有良好的相似性,能够比较准确地反映基坑开挖土体压力、变形的演变规律。本工程基坑水平位移监测点最大位移为25.96 mm,小于监测报警值30 mm。其中基坑侧壁水平位移监测是重点。分析了造成数值偏差的三大原因,对于深基坑支护结构设计具有一定的参考价值。

Foundation pit excavation will cause settlement and displacement of surrounding existing buildings and roads.In order to study the influence law of soil unloading on the surrounding buildings during pit foundation excavation,the application of pile-anchor retaining structure in deep foundation pit was studied by taking the deep foundation pit project of Anhui Bright Pearl Mall as the research object.Through theoretical analysis,field measurement and Fast Lagrangian Analysis of Continua 3D(FLAC_(3D))numerical simulation,the supporting structure was comprehensively analyzed,and the deviation between the measured displacement data and numerical simulation results of the supporting structure and surrounding environment during the excavation process of the foundation pit was compared.The results show that:the model results are generally similar to the field measured data by using the software of FLAC_(3D) to perform numerical simulation,which can more accurately reflect the evolution law of soil pressure and deformation in foundation pit excavation.The maximum displacement of the horizontal displacement monitoring point of the foundation pit of this project is 25.96 mm,which is less than the monitoring alarm value of 30 mm.The horizontal displacement monitoring of the sidewall of the foundation pit is the key point among them.The three major causes of numerical deviation are analyzed,which has certain reference value for the design of deep foundation pit supporting structure.