The Analysis Of Deformation And Supporting Interaction About A Deep Foundation Pit In Shijiazhuang

With the rapid development of the national economy and urban construction, the deep foundation pit engineering has widely applied in the whole country. But there are a lot of questions in the design and construction of deep foundation pit, such as some latent problems in the imperfect theory of supporting structure design, the unreasonable selection of supporting structure and the unreasonable control of deep foundation pit deformation. In addition, deep foundation pit engineering is a discipline in a wide range of the application, the engineering geological condition is very different in different areas. These factors all make the design and construction of deep foundation pit engineering more complicated.Deformation control of deep foundation pit supporting structure is the chief problem on ensuring the safety of foundation pit. This paper briefly introduces the supporting structure, design elements and the reasonable selection of the deep foundation pit supporting structure commonly used in deep foundation pit engineering design and construction. This paper expounds the deformation forms of deep foundation pit, the influencing factors of deformation, the deformation control standards and measures to reduce the deformation. Focus on a deep foundation pit engineering in Shijiazhuang city as an example, on the basis of the monitoring data, using the large finite element software PLAXIS to simulate the whole process of excavation and supporting of deep foundation pit. And it is concluded that the ultimate deformation situation compared with the actual monitoring value analysis and fitting. Then simulation and study the deep foundation pit deformation situations under six conditions of the different pile bending stiffness, axial stiffness of pile, soil conditions, anchor cable free end axial rigidity, axial stiffness and prestress anchor cable anchor end respectively.We can draw the following conclusions through the deep foundation pit simulation analysis in Shijiazhuang city. The location of the maximum horizontal displacement of pile occurrs in the lowest position of the deep foundation pit. The location of the maximum horizontal displacement of pile changes little when change the above six conditions. But increasing the pile bending stiffness and prestress can effectively reduce the horizontal displacement value of pile body. It impacts on the horizontal displacement value of pile body little when increasing pile axial rigidity, anchor cable free end axial stiffness, anchor cable anchor end axial stiffness. The different soil conditions affected the horizontal displacement of the pile body a lot.