Comprehensive Mechanical Analysis Model for Stability of Thin Sidewalls Under Localized Complex Loads

This study proposes a mechanical model for evaluating the stability of thickened structural walls (TSWs) under complex local loading conditions. The model allows for the calculation of stress distribution and yielding status of TSWs based on the Drucker–Prager (D–P) yield criterion. Compared with two existing theoretical models, the proposed model improves calculation accuracy by approximately 5% and 53%, respectively. The analysis results indicate that the maximum principal stress of TSWs primarily occurs at the midpoint of the left boundary (0, h/2), the center of lateral loading on the bottom boundary (LP, 0), or the center of lateral loading (LP, h/2). As the lateral load position (LP) and width (LW) increase, both the maximum principal stress and the yielding area increase. Increasing the sidewall thickness (ST) and length (SL), while reducing the sidewall height (SH), significantly enhances the overall stability of TSWs. To meet residual ore recovery requirements, it is recommended to increase SL and reduce LP, LW, and SH. In the residual ore recovery project of the Jubankeng tungsten mine, the critical thicknesses of four TSWs were calculated using the proposed mechanical model, yielding values of 4.6 m, 4.2 m, 2.6 m, and 11.9 m. Based on field validation conducted in stopes V3412 and V3301, the discrepancy in maximum principal stress (MPS) between the mechanical model and numerical simulations was within 4% for both cases, further confirming the accuracy and applicability of the proposed model in engineering practice.