3-Dimensional FEA for the interaction between supporting structure of excavation and soil in a very deep pit

The size of a very deep pit is about 69 m×50 m×50 m and it is difficult to be analyzed with traditional approximate method. In order to reveal the deformation and internal force of its 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 scheme, the influence of groundwater 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 supporting forces between the two cases will be 1.5 times.At the same time, the excavation scheme and ground water lowering are also important for the deformation and internal force of the support. The analysis results show that investigation of the interaction between soil and structure and simulation of excavation process are necessary in such complex problems.