| The traditional reinforced concrete bracing system is polluting to the environment and cannot be reused,and the monopole steel internal bracing has the characteristics of poor integrality,but the assembled H-beam combined internal bracing as a new horizontal internal bracing system has the advantages of being recyclable,polluting to the environment less,and having greater stiffness and significantly shortening the construction period,etc.In this paper,for the H-beam combined internal bracing system,we use " Midas GTS" three-dimensional finite element numerical simulation and "Tongji qixing" software are used to simulate and calculate the whole process of excavation and support of an underground parking lot in Maanshan,and the method of theoretical analysis,finite element simulation combined with field monitoring data is used to discuss the temperature change,stiffness and soil excavation volume.The relationship between the stability of the assembled H-beam combined internal support in the foundation pit project was investigated by using theoretical analysis,finite element simulation and field monitoring data,mainly to provide guidance for the foundation pit support design stage.The main research contents and results of this paper are as follows.(1)Theoretical calculation analysis of the research related to the stability of assembled H-beam combined internal support in foundation pit engineering,mainly doing the theoretical derivation of the stiffness coefficients of angle braced and octagonal braced,the theoretical analysis of the influence of temperature change on stability and the theoretical analysis of the influence of earth excavation on stability,analysis of the strength of the cross-section of assembled H-beam combined internal support beam and its stability verification method,and drawing stability related Conclusion,and take a foundation pit project in Maanshan as an example for calculation and verification.(2)According to the engineering geological conditions,hydrological conditions and the surrounding environment of a proposed project in Maanshan,the design and calculation analysis of the support scheme were carried out,and two software programs "Tongji qixing" and "Midas GTS" 3D finite element numerical simulation were used to investigate the proposed support scheme respectively.The proposed support scheme was subjected to unit calculation and spatial analysis,and the proposed support scheme was tested for stability.(3)According to the proposed support scheme,Midas GTS was used to carry out3 D excavation simulation to analyze the horizontal displacement of the soil around the pit,the axial force relationship between the angle brace and the counter brace in the assembled H-shaped steel combination internal support,and the horizontal displacement of the encircling pile,and compare the simulation results with the theoretical calculation results to investigate the stability of the assembled H-shaped steel combination internal support in the pit project.The simulation results are compared with the theoretical calculation results to investigate the stability of assembled H-shaped steel composite internal support in foundation pit project.(4)On-site monitoring of the foundation pit project is carried out,and the monitoring data are compared with the finite element numerical simulation results to verify the accuracy of the conclusions related to stability from the finite element numerical simulation analysis.The experimental scheme of the effect of temperature change on the axial force of the combined internal support of steel sections is also developed,and the conclusions from the field experiments are compared and analyzed with those from the theoretical derivation to verify the accuracy of the theoretical derivation. |
PDF Full Text Request