The Stability Research Of Internal Brace Support System Under Asymmetric Load In Deep Excavation

With the development of urban construction,more and more large deep foundation pit,the surrounding environment and geological conditions are also different.The current researches mainly focus on the load around the foundation pit is symmetric,both finite element simulation and structure optimization design,is the role of symmetry around the foundation pit under load,and in engineering practice,a considerable part of the excavation are asymmetric load problems,such as high field,different landmarks and permanent temporary buildings building materials,stacking and temporary pile caused by load around the foundation pit and sometimes there are different,different and dig deep foundation pit soil etc.Due to the influence of the hydrogeological conditions and the asymmetric load around the foundation pit,the stability of the support structure of the row piles internal support system is lack of in-depth study.In this paper,Xu Dong Harbourside foundation pit project,for deep foundation pit under asymmetric load supporting system was studied,which finds out the existing rules,and provide the basis for the optimization design,the main contents are as follows:(1)This paper introduces the domestic and foreign asymmetric loads of row piles in supporting the research status,the supporting system of the characteristics,theoretical analysis and calculation method.(2)In the deep excavation of Wuhan Xu Dong Harbourside A land as the basis,using the geotechnical engineering numerical analysis software MIDAS/GTS to establish three-dimensional model of foundation pit,construction conditions of different simulation of excavation process,found in asymmetric load in row piles supporting body line displacement,bending moment and internal change of axial support force,combined with the data support monitoring of foundation pit,and MIDAS/GTS numerical simulation are analyzed and compared.(3)Using MIDAS/GTS software,the pit surrounding load changes,support number,support section size,support pile spacing,pile diameter and other factors on the influence of deformation and internal force of supporting system and analysis,thus obtains the effect of asymmetric load,different influencing factors on retaining pile and inner support force,influence deformation,provide a theoretical basis for the optimization design.(4)Through the MIDAS/GTS software simulation,the optimization program is a supporting pile,support size and reinforcement component are calculated,that after the optimization of a reinforced concrete support in supporting pile,support size and reinforcement components than the conventional two brace size and reinforcement too large,despite the maximum horizontal displacement of an internal bearing and bending moment of pile is lower than the conventional two inner supporting structure to be big,but the MIDAS/GTS simulation data showed that the displacement,deformation and internal forces are within the range of the specification,only the displacement,deformation and internal force of large parts of the supporting plate increase increased.The local integral rigidity and stability.Based on the optimized support scheme of Tianhan software analysis calculation,further simulation results of the MIDAS/GTS review,to ensure the safety of foundation pit supporting scheme,reduce project cost.And the surrounding environment and the whole supporting structure of the real time monitoring,monitoring data analysis and timely feedback,the implementation of information technology,the dynamic construction of the whole process to ensure the safety and stability of foundation pit construction.