Design Of Deep Foundation Pit Supporting System In Thick Clay With Composite Soil Nailing Wall

Composite soil nailing wall,refers to the soil nailing wall with one or several single support technology or water cut technology combined into the composite system,its components are mainly soil nails,prestressed anchor,Cut curtains,micro-piles,hanging net spray concrete surface layer,in situ soil and so on.The composite soil nailing support technology has the advantages of simple construction,low cost and good supporting effect,and is widely used in deep foundation pit engineering.Based on the foundation pit engineering of Rong'an in Guangxi,this paper adopts the method of theoretical analysis and finite element simulation to select the supporting scheme of the foundation pit and carry out the design of composite soil nailing wall,and then the numerical simulation results And the composite soil nailing wall design results were compared and analyzed,and finally the model was optimized.The main contents and conclusions are as follows:(1)According to the type of deep foundation pit,the principle of deep foundation pit support scheme selection,the choice of support program,comprehensive analysis of composite soil nailing wall selection program.(2)The design of composite soil nailing wall is carried out by using deep foundation pit software.The main design part is steel pipe pile,prestressed anchor and soil nailing.The deformation characteristics of the composite soil nailing wall structure during the excavation of the foundation pit are analyzed,and the stability test,the anti-overturning stability check and the anti-uplift check are carried out.(3)The numerical analysis method is used to analyze the deep foundation pit of the thick clay layer.The horizontal displacement and vertical displacement,the surface subsidence,the prestressed anchor cable force,the horizontal displacement of the steel pipe pile and the horizontal displacement Internal force characteristics,and with the composite soil nailing wall design were compared.Through the comparison of the numerical model,it is concluded that the double-row steel pipe pile composite soil nailing wall has better safety performance than the single-row steel pipe pile composite soil nailing wall.