Study On Support Optimization And Positive Angle Stress And Deformation Of Irregular Shape Deep Foundation Pit In Wuhan

With the rapid development of city construction, Higher requirements of city underground space utilization rate is proposed. The problem in the field of engineering becomes more and more complex with the increasing super high-rise buildings, subway engineering, underground shopping malls. As a complex problem in geotechnical engineering, the deep foundation pit has increasingly attracted the attention of experts and scholars, who has achieved a lot of successful experience. At present, for the regular shape foundation pit, it has formed an analysis method and theoretical system. However, the study of irregular shape foundation pit is relatively less, especially for the stress and deformation of deep foundation pit with positive angle.It only proposes the importance of the stress and deformation of foundation pit with positive angle in the building excavation monitoring technical specifications.however, it doesn’t contrast with other part of foundation pit. Therefore, in view of the irregular foundation pit problems, this paper is mainly engaged in the following several aspects of research:(1) Based on the foundation pit monitoring data collation and analysis, draw the curve of lateral displacement of retaining wall changes, crown beam settlement, crown beam lateral displacement, axial force project which change with time. Through the analysis the curve deformation trend of different measuring points, we can point out the deformation of foundation pit has obvious effect of three-dimensional space, for example,the deformation fo foundation pit positive angle in the middle of retaining wall is significantly greater than the deformation of the end position of retaining wall.(2) According to the geotechnical parameters which is supposed in the foundation pit engineering geological investigation and foundation pit supporting design scheme, it is modeled by the finite element program Ansys and introduced into the Flac3 d for calculation. According to the results of analysis, draw the curve of the retaining wall lateral displacement and ground settlement, reinforced concrete meter axial force, bottom rebound deformation in different conditions. Contrasting the curves of different projects, we can get that the maximum deformation increasing conditions, and then find the critical step of excavation, to provide guidance for the excavation of foundation pit.(3) According to the excavation simulation results and the analysis of the influence of different supporting ways which cause force and deformation of foundation pit positive corner, to find out the best way to decrease the stress and deformation of foundation pit with positive angle.(4) Based on the study of the stress and deformation of corner space and axial force of support with different angle positive corner, this paper points out that with the increase of the positive corner angle,the deformation of overcast corner is lower,while the deformation of positive corner is greater. The maximum stress occuer at the positive corner when the positive corner angle is 145°,when the angle is greater than 150 ° the phenomenon of stress concentration of positive corner disappear gradually.