The Study On The Deformation Property Of Combined Foundation Pit Support Of Soil Nailing And Pile-interal-struct

The soil nailing and pile-interal-struct combined support is a new form of support structure which combine the pile-interal-struct and soil nailing wall to using in excavation.This form of supporting can effectively take advantage of the advantages of both the supporting structure and improving support efficiency.It has been successfully applied in Changsha Metro deep foundation pit design.Based on the study of one open-cut station of Changsha Metro Line 3,the theoretical calculation,field monitoring and finite element simulation has been used combined to calculate the deformation of retaining structures and deformation law of retaining structures.The main contents and conclusions are as follows:(1)Describes the characteristics of soil nailing row piles combined support structure and explains this kind of support not only economical,but also safe and reliable through the analysis and summary of the current research(2)According to the combined support retaining structure feature,the soil nailing part will be regarded as vertical load in the top of the pile by combined support structure equivalent calculation model and the elastic sub grade was used to calculate the deformation of supporting structure.The results show that the horizontal displacement of pile continued to increase with excavating,and deformation curve is multi fulcrum envelope feature.(3)Study on site monitoring data and focus on the analysis of the deformation of retaining structure and ground settlement around the pit during excavation with the excavation depth and the variation of time.(4)The elastic plastic finite element analysis method was used to simulated deep station foundation and analyzed the deformation feature of pit and retaining structure during excavation,and compared with the measured data.