Stability Analysis of Jinan Qixiuchang Metro Station during the Foundation Pit Temporary Supports Dismantling

Abstract

Objective It is prone to lose stability, affecting the engineering safety in the process of dismantling the supports for metro station deep and large foundation pit. Therefore, it is necessary to analyze the stability in the above process. Method Based on the deep and large foundation pit project of Jinan Qixiuchang Metro Station, on-site monitoring and three-dimensional numerical simulation are used to study the deformation characteristics and the dynamic evolution of mechanical response during deep and large foundation pit excavation and the supports dismantling, focusing on problems like supporting axial force, deformation of underground diaphragm wall and land subsidence. Result & Conclusion When the excavation is completed, the depth point where the underground diaphragm wall shows the maximum horizontal displacement is 0.7~0.8 times the total excavation depth. After the bottom steel support is removed, the diaphragm wall deformation accelerates and the axial force of the first support increases by 4 to 6 times. In order to ensure the construction safety, the unsupported time should be reduced as short as possible. The main ground area affected by foundation pit construction ranges from 0 to 20 m, and should be the focus of monitoring. On-site monitoring results verify the effectiveness of the numerical simulation.

Keywords

• metro station
• deep and large foundation pit
• supports dismantling
• stability analysis