Stability Analysis And Design Optimization Of T-shaped Deep Foundation Pit At Changning Avenue Station Of Hefei Metro

In recent years,with the rapid development of cities,subway has become one of the important ways to alleviate traffic congestion.There are 11 planned metro lines in Hefei,and the first line was opened and operated in 2016.Taking the deep foundation pit engineering of Changning Avenue T-shaped transfer station of Hefei Metro Line 4 and 7 as the research background,the mechanical and deformation characteristics of the foundation pit engineering in the construction process are analyzed by field monitoring and numerical calculation method,and the support structure scheme at the transfer joint is optimized.The main research contents are as follows:(1)In the process of foundation pit construction of Changning Avenue Station,we participated in the field monitoring of foundation pit construction of Changning Avenue Station,collated and analyzed the monitoring data of each stage of foundation pit excavation process,and focused on the ground settlement around foundation pit of Changning Avenue Station,the horizontal displacement of retaining structure and the change of internal support axial force in different construction stages.(2)Using Midas GTS/NX finite element software,the whole process of foundation pit excavation and support of Changning Avenue Station is numerically simulated.Firstly,the field monitoring results and numerical simulation results are compared and analyzed to verify that the finite element numerical simulation method is accurate in analyzing the construction process of the foundation pit of Changning Avenue Station.At the same time,the surface settlement,horizontal displacement of retaining piles,supporting axial force and the bottom heave of the foundation pit produced in the dynamic excavation simulation process of the deep foundation pit of the T-shaped transfer station are also verified.The law of change is analyzed and summarized.(3)In view of the problems encountered in the actual construction of the foundation pit at the transfer node of Changning Avenue Station,the internal support structure of the foundation pit at the transfer node is optimized and analyzed.Firstly,three optimization schemes of primary selection are compared and analyzed with Qixing software,and a support structure optimization scheme with certain safety,economy and feasibility is selected.Secondly,the whole process of excavation and support of foundation pit is simulated with Midas GTS/NX finite element software,and the final optimization is verified by comparing and analyzing with the original design scheme.The case is reasonable and safe.Figure 78 table 13 reference 55...