The Analysis Of The Deformation Affecting Factors Of Double-row Piles Supporting System In The Deep Foundation Pit

Double row piles structure is a cantilevered space support system which is widely used in engineering with its fast construction and without setting inner support,greater lateral stiffness,etc.However,there are a variety of computing models in its structure and the deformation is more complex,especially for in the design of the effects of various factors on double row pile retaining system for space effect,it remains to be further study.In the analysis of double row piles supporting system calculation theory based,this paper used large-scale general finite element software ABAQUS to establish a three-dimensional finite element model of double row piles,studied the effects of different factors on the stress and deformation influence of double row piles supporting system in deep foundation pit,and through the engineering example it is validated.The main contents of this paper are as follows:(1)First,this paper describes characteristics,advantages and disadvantages and research status of the double row pile supporting system;Secondly,several different theoretical calculation methods are introduced in detail;Based on ABAQUS finite element software,this paper introduces the element type,the selection of the constitutive model,the contact problem of piles,the establishment of 3D model and the simulation of excavation.(2)This paper established the three-dimensional finite element model and analyzed the influence of different factors for the stress and deformation of double row piles supporting system in the deep foundation.These factors include excavation depth,excavation width,double row pile spacing,pile length,pile diameter,soil cohesion and internal friction angle,and so on.It results: increasing the width and the depth of excavation,horizontal displacement of piles gradually increase;4d(d is the diameter of the pile diameter)is proposed to control the row spacing of the piles;The length and diameter of pile can effectively control the increase of horizontal displacement of double row piles supporting structure;The increase of soil cohesion and angle of internal friction,can reduce the horizontal displacement of double row piles supporting structure.(3)Taking a deep foundation pit engineering in Tianjin as an example,the finite element simulation results are compared with the observed data.The rationality of the finite element model is verified,and the reference value of different factors is proved.