Excavation deformation analysis of subway foundation pits based on finite element analysis

The excavation deformation of subway foundation pit engineering is limited by the engineering characteristics. There is a risk of collapse lag and incalculable consequences. To improve the safety factor in subway foundation pit construction and prevent the risk of foundation pit collapse, finite element analysis was utilized to simulate the deformation of subway foundation pit excavation. Meanwhile, a risk assessment method for the collapse of foundation pit support was constructed by combining the fuzzy hierarchical comprehensive evaluation model in the experiment. Numerical analysis confirmed that the maximum horizontal displacement of the foundation pit when excavated to the bottom was 11.96 mm, and the maximum surface settlement was 11.50 mm. These simulation results were highly consistent with the measured curve, with a maximum displacement difference of only 2.87 mm and a maximum settlement difference of 2.00 mm. According to the proposed method, foundation pit engineering’s evaluation was carried out, with a support structure score of 0.437, a surrounding soil score of 0.450, a bottom soil score of 0.267, and an overall project risk score of 0.416, all within an acceptable range. Therefore, the method of simulating and predicting excavation deformation of subway foundation pits using the finite element software is effective and reliable. According to the risk assessment results of foundation pit collapse, relevant management personnel should strengthen and attach importance to the prevention of collapse of the surrounding soil and support structures of the foundation pit.