Research On Support Design Of A Deep Foundation Pit Project In Guangyuan City, Sichuan Province

In the form of the rapid development of today's society,especially the development of the city so that human demand for space increased dramatically,due to the development and utilization of land area is limited,making the human turn to the air and underground development.With the depth of the excavation depth gradually increased,the difficulty of the design of foundation pit support is also getting higher and higher.In this paper,a deep foundation pit in Guangyuan City,Sichuan Province is taken as the object of study.Based on the collection of large amounts of data,the engineering geology and hydrogeological characteristics of the foundation pit are analyzed.The incremental method and total stress method are used to analyze the The excavation process and the sensitivity of the foundation pit are analyzed by ansys finite element analysis method.The main contents and conclusions of this paper are as follows:(1)The research and research on the design of foundation pit support at home and abroad are reviewed and analyzed,and the present research situation of foundation pit support is summarized and summarized.(2)Engineering geological surveying,drilling and sampling experiments in the study area,and obtain geological data such as engineering geological features and hydrogeological characteristics of the study area.(3)According to the engineering geology and hydrogeological conditions,combined with the surrounding environment of the study area,the support scheme of the study area is taken as follows:the support scheme of" Soldier Pile with Supporting " is adopted on the east and north and south sides,Practice and reverse practice method;the west side of the second phase between the use of "part of the Step-Slope and suspended mesh gunite technology "support program.(4)Based on the calculation method,the earth pressure,displacement,bending moment and shear distribution,soil settlement,integral stability coefficient and anti-overturning coefficient of the row pile under 5 working conditions are calculated by incremental method and total stress method.The results show that the foundation pit support scheme is feasible.(5)The calculation model of foundation pit excavation is established and the corresponding simulation parameters are given.Using the ansys finite element analysis software,the strain and deformation characteristics of the sidewall soil and supporting facilities during the excavation of the foundation pit are analyzed and studied.The results show that the horizontal displacement,settlement range,settlement and horizontal displacement of the pile are obviously increasing during the excavation process,and the distance between the farthest potential slip surface and the foundation pit is gradually increasing And the plastic deformation zone gradually decreased,the plastic area gradually increased,but the internal support to reduce this trend.Row stress distribution from top to bottom is gradually increasing and symmetrical characteristics.(6)The influence of different parameters on the design of foundation pit support is simulated and calculated.The main parameters are cohesion force c and internal friction angle cp and internal support.The position of the maximum horizontal displacement of the sidewall of the foundation pit is smaller than that of the cohesion c,the internal friction angle ? and the internal support prestress.According to the linear regression prediction,the sensitivity of the internal friction angle and the maximum horizontal displacement is 0.2002,and the sensitivity of the cohesion and the maximum horizontal displacement is 0.0687,and the sensitivity of the inner support prestress and the maximum horizontal displacement is 0.0007.The influence of the internal friction angle on the maximum horizontal displacement is relatively large.