Simulation for the Construction Process of Deep Pit
Abstract: The size of a very deep pit is about 69กม50กม50m. The excavation support structure in this pit is continuous concrete wall with internal support structure, and the continuous wall is embedded into bedrocks. In order to know the safety margin and the damage process of this pit, 3-D nonlinear finite element analysis with excavation simulation is carried out. The self-weight of soil in the finite element model is increased hypothetically until the support structure is destroyed. Comparing the assumed self-weight of soil to the real one, the safety margin of the pit can be obtained. The numerical results show that all the failure of the pit begins with the collapse of the internal supports and the failure models are different in various excavation depths.
Keywords: deep pit; spatial finite element analysis; damage model; safe margin
Abstract: The size of a very deep pit is about 69กม50กม50m and it is difficult to analyze with traditional approximate method. In order to know the details of the deformation and internal force of the excavation support structure, spatial non-linear finite element analysis is carried out in which the excavation process is considered. The interaction between the excavation support and the soil, the difference between various excavation plans, the influence of ground water lowering and sensitive analysis of critical parameters are discussed in detail. The numerical results show that the deformation of the continuous concrete wall with interaction effect will be 10 times of that without interaction effect, while the difference of support axial force will be 1.5 times in the two cases. At the same time, the excavation plan and ground water lowering are also important for the deformation and internal force in the support. The analysis results show that the interaction between soil and structure and simulation of excavation process are necessary in such complex problems.
Keywords: interaction, deep pit, spatial finite element analysis