Risk Assessment Method of Internal Support Structure and Feasibility Study of Dismantling the Support

The study of risk assessment methods of internal support structures, which are widely used in the construction of deep foundation pit projects, can timely discover the risks existing in the construction process and effectively reduce the probability of engineering accidents. Starting from the actual needs of the project, the typical deformation and internal force monitoring data of the internal support structure were summarized as safety evaluation indexes. The monitoring alarm values were used as evaluation scales to quantify each index. According to the Analytic Hierarchy Process (AHP) theory, a risk analysis method based on on-site measured data was established, and the rationality of the risk assessment method was verified through practical engineering. Finally, a finite element three-dimensional simulation model was established using PLAXIS3D software to analyze the feasibility of the support demolition stage. The study shows that the problem of taking the corresponding weights of each evaluation index is the key to influence the risk level of the foundation pit, and the pile body measurement inclination, as the main safety evaluation index, should play a controlling role in the process of risk analysis. It is suggested that the risk degree should be strictly controlled below 0.6 in the actual project to ensure that the foundation pit is in a safe state.