| With the development of urbanization,the application of underground engineering,especially deep foundation pit engineering in the city is increasing day by day.In order to solve the new problems encountered,more and more engineering methods have emerged,and the development of foundation pit engineering goes far beyond the extent of its theoretical development.Whether these novel methods are reasonable,and how to maintain the balance between the reasonable control of the safety and the deformation and the economic efficiency of the deep foundation pit engineering in practice,so it is necessary to carry out in-depth study.Based on the previous research on deep foundation pit engineering,the deformation mechanism of foundation pit excavation is analyzed in this paper,and the natural factors,design factors and construction factors of foundation pit deformation are summarized.The deformation law of deep foundation pit supported by the concrete diaphragm wall and the inner supporting structure is obtained based on the analysis of monitoring data of the surface subsidence,the horizontal displacement of the concrete diaphragm wall and the internal support axial force from the deep foundation pit engineering of the third phase of the Beijing Metro Line 8,Yongdingmenwai station.Space-time effect and the characteristics of the deformation of the foundation pit under different working conditions are also studied in this paper.Combined with the particularity of this project,and the deformation characteristics of the foundation pit under various new working conditions such as the underwater excavation and bottom sealing of the foundation pit are analyzed,the drainage and the recharge of the water in the pit,and the deformation rule of the underwater excavation is summarized.The numerical simulation software Midas/GTS is used to model and analyze the actual engineering.The simulation results are compared with the monitoring data to verify the accuracy of numerical simulation and analyze the deformation law of the foundation pit more intuitively.The effect of partition wall on the deformation of foundation pit is verified by numerical simulation.On the basis of accurate numerical simulation,the factors influencing the deformation of the foundation pit are analyzed by numerical simulation method.The effects of the wall thickness and embedded depth,the influence of the partition wall arrangement on the deformation of the supporting structure is put forward,and the optimization suggestions are made for the design of the wall.The law value of m is analyzed based on the deformation analysis,and the optimization of the design parameters is put forward. |
