Research Of Retaining Wall Reinforced In The Passive Zone Of Deep Soft Soil Foundation Pit

With the continuous improvement of China’s unbanization and the economy development, the urban land becomes less, making the city more and more develops to the underground space, thus, the problem what we must mention is the retaining and protection of foundation excavation. The situation that the buttom of foundation pits lie in the deep soft soil becomes more common, in this case, the primary problems are supporting structure’s stabilization and the horizontal displacement too large. Large researches and practice shown that reinforce the passive zone of deep soft soil foundation pit can improve the supporting structure’s stabilization and control the horizontal displacement, but the effect of the passive zone reinforcement relate to the width and depth of the passive zone reinforcement and cement content, thus, the primary problem is how to determine the width and depth of passive zone reinforcement and the cement content in the project. This thesis used Midas GTS NX to simulate and analyze, and then calculated by the link finite element method, with the background of Baoyin foundation pit in Longjiang town, Foshan city, studied the effect of increasing the resisting force of the passive zone reinforcement. The main research contents of this thesis can be summarized as follows:(1)Firstly, based on the large researches, summarized the current research status and method of passive zone reinforcement, and then defined the research direction of this thesis, demonstrated the rationality and feasibility of the research mothed;(2) By using Midas GTS NX finite element software to simulate the project, compared the results of calculation and the actual monitoring, proved the finite element model that established by Midas GTS NX was right;3)Based on the finite element moded, adjusted the width and depth of the passive zone reinforcement and the cement content, analyzed the pile’s deformation curves of different models, and then calculated the pile’s deformation by the link finite element method, compared the results of finite element simulation and calculation, can obtain the m-values of complex soil when the results of finite element simulation and calculation were close;(4)Analyzed the m-values of different reinforcing models, and then summarized the law of m-values;(5)corrected the m-values formula of specification, obtained the amendatory m-values formula that can consider the effect of width and depth of the passive zone reinforcement and cement content, besides, verified the amendatory m-values formula by one real project.