Study On Construction Deformation Characteristic Of Deep Foundation Pit Of A Tunnel Working Well

With the rapid development of modern urban construction, and further development and utilization of underground space, the deep foundation construction on the surrounding environment influence has been highly valued. How to control the retaining structure deformation and soil displacement around deep foundation, protect the surrounding buildings and public facilities is the question which must be considered in excavation process. Background in Pudong working well of Shanghai West Changjiang Road Tunnel, a series of studies for deformation law and control measures of retaining structure and soil in the whole process of excavation and supporting construction of deep foundation in soft soil area is carried out, the main contents are as follows:1.At the excavation process of foundation with depth of 28m of Pudong working well of Shanghai West Changjiang Road Tunnel, retaining structure deformation and surrounding displacement of soil are actually measured and researched, and the appropriate monitoring scheme is formulated according to the design and construction project of supporting structure of this foundation. In different conditions, the lateral displacement and the vertical displacement of diaphragm wall, the settlement of lattice column and soil behind the wall, the axial force of struts, and the settlement of existing buildings are made on monitoring in the whole process. A profoundly analysis is made to monitoring results, then obtained the laws of the displacement of diaphragm wall varied with depth, the settlement of lattice column and the vertical displacement of diaphragm wall varied with time, the axial force of struts varied with time, and the settlement of soil behind the wall varied with horizontal distance, can provide a reference to design of same foundation.2.The full construction process of the retaining scheme in this project was simulated by three-dimensional finite element software-ADINA according to the actual construction conditions, the nonlinear of soil and interaction between soil and structure are considered in simulation process. The displacement of diaphragm wall, soil resilience, the axial force of struts, the displacement of soil behind the wall, and so on are obtained in different conditions.3.The actual measurement data and numerical simulation results are compared in the project of Pudong working well of Shanghai West Changjiang Road Tunnel, the reason of being differences and lack of numerical simulation is analyzed, can propose a reasonable advice for the design of deep foundation.