| The construction of shield tunneling method has its unique characteristics such as safety, high degree of automation and rapidity. However it will also disturb or destroy the soil body with different degrees, and result in ground movement and deformation, even induce a series of questions, such as surface. subsidence, tunnel gushing, damage of surrounding buildings. Consequently, it appears especially important that selecting appropriate construction technology parameters based on different geological conditions.Based on a shield project segment of Beijing subway, this paper uses finite element method to simulate the process of shield tunnel excavation. Disciplinarian of stratum settlement under different technical parameters such as soil warehouses pressure and grouting pressure was analyzed. Following are the main contents of research and conclusion:(1) The deformation disciplinarian of sandy cobble stratum in the process of shield tunnel excavation and the reasons of stratum settlement are discussed.(2) According to the engineering geological conditions, a3D tynnel model was established to simulate the tunnel excavating by mean of the Finite element analysis software. The key factors such as the the nonlinearity of soil material, the structure void of shield and stress release rate been taken into account in this3D model.(3) According to the results of the analysis, disciplinarian of stratum settlement under different soil warehouses pressure sand grouting pressures is obtained.The reference values of technical parameters in the real engineering are given finally.(4) The selection of cutters in sandy cobble stratum are summarized. According to the real engineering, the optimization measures of cutters disposition are given. |
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