Study On Bearing Characteristics Of Double Row Piles Considering The Effect Of Soil Reinforcement Around Piles

Double row piles,as an effective form of supporting structure in the dense area of urban buildings and complex surrounding environment,have been widely used in the deep foundation pit engineering of urban soft soil.However,due to the complexity of the mechanical properties of double row piles,the current technical code for the support of building foundation pit(JGJ120-2012)fails to fully consider the effect of soil reinforcement around piles and the influence of mechanical properties of soil between piles on its design parameters.In order to further improve the design and calculation theory of double row piles,based on the existing research results,the bearing characteristics of double row piles was analyzed through theoretical analysis,model test,numerical simulation and field test.The main researching contents and achievements are as follows:(1)This paper summarizes the existing calculation theory and related research results of double row pile supporting structure was summarized,and then the problems and shortcomings of various calculation models of double row pile supporting structure were analyzed.(2)Based on the comprehensive consideration of the influence factors of the reaction at the bottom of coupling beam on the pile top and pile side friction on the bearing behavior of double row piles,an improved calculation model of double row piles is established.(3)Based on the indoor model test,the five working conditions of soil between piles were analyzed,which are not reinforced,embedded in the bottom of piles,soil between piles,passive area reinforcement,soil between piles and passive area reinforcement respectively,and then,the deformation and internal force distribution of double row piles under different reinforcement conditions were discussed,and some reference was provided for engineering practice.(4)Based on the above research results,a deep foundation pit of soft soil wastaken as an example,the bearing characteristics of double row piles are compared and analyzed through the research methods of three-dimensional finite element simulation,model test,theoretical analysis and field test,for the more,the results of theoretical analysis and model test have been proved to be reasonable.The research results of this paper have certain reference significance for improving the design and calculation theory of double row piles and optimizing the design parameters of double row piles.