Dynamic Construction Deformation Analysis Of Deep Foundation Pit Support Struction Based On Soil Harding Model

Nowadays, the underground foundation of underground buildings is developing in a deeper and deeper direction, which is a great challenge to the requirements of construction site and construction environment.Therefore, the application of reverse construction method is of great significance. Compared with the conventional method, the method has the advantages of shortening the construction period, the influence on the surrounding environment and saving the construction cost, which opens up a new world for the underground construction of the city. However,there are still a lot of potential problems to be solved urgently in the theoretical and practical application of the construction technology of reverse construction. We need to carry on the continuous exploration research and provide a more perfect analysis method for the reverse construction technology.Based on the construction of the foundation pit, the deformation of the foundation pit is carried out, and the deformation of the foundation pit is carried out. The back analysis method is used to analyze the finite element model of the HS and the deformation of the foundation pit is carried out by numerical simulation. The dynamic prediction analysis shows the superiority of HS model and the safety of foundation pit design. The main work and research are as follows:(1) Based o the basic theory of reverse construction method, the difference and advantage between the construction technology of reverse construction method and construction technology are analyzed. The classification of construction technology and the prospect of research and development in recent years are summarized.(2) The horizontal displacement of the top of the underground continuous wall, the settlement of the ground around the foundation pit,the horizontal displacement of the underground continuous wall, the uplift of the foundation pit and the deformation of the settlement of the building are analyzed and studied in the process of the reverse construction of the project. The safety of the foundation pit engineering design is verified.(3) In this project, the construction process of the foundation pit is divided into the following ten working conditions : initial stress field simulation, piling underground continuous wall construction and pressure roof construction, excavation of the basement roof cover,construction of the basement of the basement floor, excavation basement layer of soil body, the construction of the basement of a layer of floor,excavation of the basement of the second floor of the soil, the construction of the basement of the second floor of the basement,excavation of the basement of the three layers of soil and the construction of the basement floor. Based on the measured data of the deformation of the foundation pit, the parameters in the H-S model are solved by the displacement back analysis method in geotechnical engineering. The deformation curves of the foundation pit which are solved by the H-S model and the M-C model are compared and analyzed.The optimal combination of H-S model is obtained.(4) Based on the research and summarization of the existing reverse engineering project, the finite element software PLAXIS is used to simulate the excavation of the foundation pit. The boundary conditions and model dimensions of finite element numerical simulation are determined by the basic situation of foundation pit. The results show that the H-S model is superior to the M-C model in the simulation of foundation pit excavation. The results show that the H-S model is better than the M-C model, and the H-S model is used to simulate the foundation pit. The horizontal displacement of the underground continuous wall, the horizontal displacement of the foundation pit and the settlement and deformation of the pillar and the underground continuous wall during the excavation of the foundation pit are simulated and analyzed by using the PLAXIS finite element software under the H-S model. Finally, the concept of information construction is put forward. The large-scale deep foundation pit project should be integrated into the field monitoring, theoretical analysis and forecasting, and effectively guide the construction of the project safety.