Stability Analysis and Support System Timing for Mine Block ۳ of Parvadeh ۴ Coal Mine Using Numerical Modelling

Ensuring the stability of the main inclined shaft in coal mining operations is of particular importance. The instability of inclined shaft seriously restricts the safe and efficient mining of coal resources. In this paper, stability of main inclined shaft of mine block ۳ of Parvadeh ۴ coal mine in Tabas is modeled to design support system and to determine its optimal installation time by using the finite difference numerical method. To assess the stability conditions of the excavation, we employed the empirical method introduced by Barton, which facilitated the proposal of an appropriate support system. Subsequently, to evaluate the proposed support system and ascertain its optimal installation time, numerical simulations were conducted using Fast Lagrangian Analysis of Continua in ۳ Dimensions (FLAC ۳D) software. This involved analyzing the rock mass properties surrounding the main inclined shaft, understanding the mechanics of the surrounding rocks, and applying in-situ stresses and boundary conditions within the model. The results indicated that the optimal timing for installing the combined support system—comprising shotcrete with a thickness of ۱۰ centimeters, a mesh frame with a diameter of ۶ millimeters and a spacing of ۱۵ centimeters, along with designed rock bolts—occurs during the initial stage of drilling and bolt installation, accompanied by stress release. In the final phase, to evaluate the proposed support system, the interaction diagram (bending moment-axial force diagram) obtained from the SAP۲۰۰۰ software was analyzed. The findings from this section demonstrated that the proposed support system exhibits satisfactory performance against axial force and bending moment in the given conditions.

کلیدواژه ها:

Numerical modeling ، finite difference ، inclined shaft ، support system ، Tabas Coal mine