Study On Excavation Deformation Law And Prediction Of Hongdian Building Foundation Pit Engineering Of Shenzhen

Engineering construction is in a stage of rapid development,and the excavation depth and area of deep foundation pit engineering are increasing in China.However,since deep foundation pit projects are usually located in places with small areas and high population density,the construction of deep foundation pits will have great adverse effects on the surrounding environment.Especially in the excavation of foundation pits in soft soil areas,engineering accidents such as instability of the foundation pit and the rupture of surrounding buildings are often caused due to the failure to control the deformation value of the foundation pit.The excavation of the foundation pit must not only grasp the overall deformation of the foundation pit itself,but also effectively predict the change of the surrounding surface settlement during the excavation process of the foundation pit,so as to ensure the safety of the foundation pit itself and the surrounding environment.Therefore,this paper is based on Hongdian Building Foundation Pit Engineering of Shenzhen Building,uses Flac^3D software to establish the overall numerical model of the foundation pit,and combined with the field monitoring data,systematically studies the internal retaining structure and surface settlement deformation law outside the foundation pit during the excavation stage in Shenzhen soft soil area.A ground subsidence prediction method based on Stacking multi-model integration is proposed.The prediction results are more reasonable and reliable.In order to realize the safety and economy of foundation pit construction in the soft soil area with poor engineering characteristics and complex surrounding environment,an information construction mode combining the simulation of the whole deformation of foundation pit and the dynamic prediction of ground surface settlement is explored.The main research contents of this paper are as follows:（1）Based on Hongdian Building Foundation Pit Engineering of Shenzhen,Flac^3D software is used to simulate the overall excavation process of the foundation pit engineering,and the variation rules and characteristics of the displacement of the foundation pit retaining structure,the axial force of the support and the settlement of the surrounding surface are analyzed during the excavation process.（2）Sorting out on-site monitoring data.By combing and summarizing the actual monitoring data during the foundation pit construction,the variation law of the top displacement of the pit enclosure structure,the settlement of the surrounding surface and the axial force of the internal support structure in the time of the foundation pit construction is analyzed,so as to explore its deformation characteristics during the foundation pit construction.The variation law of the measured data from statistical analysis is compared with the numerical simulation results to verify the correctness and effectiveness of the three-dimensional finite element simulation established in this paper.（3）Prediction of surface settlement around foundation pit based on Stacking model fusion.Based on Stacking integrated learning technology,a multi-model fusion scheme for predicting ground settlement of deep foundation pits is presented.The Stacking fusion model was established based on three traditional basic models（random forest,support vector machine and artificial neural network）,and the prediction accuracy of Stacking model and three basic models was compared and analyzed.