| Deep foundation pit is one of the hot spot and very important research topics in the field of construction engineering.The supporting structure of the deep foundation pit is a key factor affecting the deformation of the foundation pit.This paper is presented the previous research results of the deep foundation pit supporting project at home and abroad.And Combined with the engineering examples of the support structure which is involved in ultra-deep foundation pit of the North Anchorage of the Yangsigang Yangtze River Bridge in Wuhan,it is developed in accordance with research methods and relevant technical route and is made about excavation monitoring scheme through geological conditions,design requirements,supporting forms,and construction processes of the project area.Based on three-dimension finite element analysis software for Midas GTS NX to establish a calculation model,considering the interaction between the soil and the supporting structure,the excavation is made a numerical simulation analysis about the excavation and supporting and the comparative analysis is combined with on-site monitoring data,the deformation and stress characteristics of the supporting structure in different excavation stages are obtained.According to the analysis of the monitoring data and the calculation results of finite element,the following conclusions are derived,combined with the requirements of safety control about the foundation pit supporting structure.First,it is summarized the purpose and significance of deep foundation pit in this paper.The particularity of this project is analyzed by combining with the actual situation,and it specifies appropriate scheme and requirements about monitoring,to be given a reasonable monitoring layout.At the same time,in order to the smooth running for ensuring monitoring,monitoring alarm values and monitoring frequency are proposed for the necessity,which,all of this can provide a reliable basis for grasping the overall safety and progress control.Second,as a research object on the project of deep foundation pit supporting structure about Hanyang side anchorage in Wuhan Yansigang Yangtze River Bridge,a three-dimension finite element simulation model for the excavation is established based on three-dimension finite element analysis software for Midas GTS NX,and the process of excavation and supporting on the deep foundation pit are simulated and analyzed to obtain the horizontal displacement,settlement,the stress and deformation characteristics of the vertical stresses and supporting structure.Third,the on-site monitoring of the foundation pit supporting structure and its deformation is carried out.The variation of the deformation of the supporting structure during the construction of the foundation pit with the depth and time of excavation.The comparative analysis is combined with on-site monitoring data.The deformation and stress characteristics of the supporting structure in different excavation stages are obtained.The results are showed that the theoretical calculation results are basically consistent with the variation of on-site monitoring data.In the process of construction about the deep foundation pit,it is necessary to control the excessive deformation of ground and monitor the internal forces of the supporting structures due to the excavation.The numerical simulation results are consistent with the on-site monitoring rules,which verifies the rationality of the finite element numerical simulation.Fourth,compared with the data of simulation and monitoring,confirm the theoretical basis and practical significance of the numerical simulation software analysis for the early stage construction guidance,and provide the reference for the construction side to take the corresponding measures during the excavation.Through detailed comparison and analysis of three-dimensional numerical simulation model and actual monitoring data.,the excavation has a certain influence on the safety of the surrounding environment,but within the control range. |
PDF Full Text Request