A multi-option RES-based model (MORESM) for selecting the optimum rock bolt system in underground coal mines

The research presents a method entitled MORESM based on the rock engineering system (RES) for selecting the optimum rock bolt (RB) for underground coal mines. This method introduces a new application of RES that simultaneously provides the possibility of comparing various options in rock engineering and validating the model based on the relevant hazards. The model is intended to operate based on routinely collected field data in underground coal mines and does not require specialized or costly testing equipment. The model is based on two key components: the interaction matrix, which determines the weights of effective system parameters, and the rating matrix, which evaluates the response level of each RB under various system conditions. The rating matrix is used to evaluate each RB’s relative efficiency by analyzing its responses compared to other RBs across different conditions, without considering the strength factors of each rock bolt, such as load-bearing capacity. This approach is applicable when outcome validation is supported by field data. Here, six RB types are involved as six options, and the model is capable of determining the risk of applying (VIap) for each RB. In the following, a case study including ۱۰۰ plus to ۱۰ locations/cases of an underground coal mine was used to test and validate the MORESM. In this regard, the amounts of roof convergence (tell-tale displacement (TTD) at considered locations) are considered as the relevant hazard caused by increasing the VIap of applied (installed) RB. The results demonstrated that there is an acceptable correlation between the determined VIaps and corresponding TTDs, with a coefficient determination (R۲) of ۰.۷۶۵, and also the measured and predicted TTDs, with an R۲ of ۰.۸۰۳. The findings also indicated that when the applied RB is far from the optimal RB, instability increases just as much. This could be considered as a criterion for evaluating the performance of MORESM. Finally, it is proven that the model could be helpful to estimate the substitution time of the applied RB with a useful option, which is investigated for the case study.

کلیدواژه ها:

Rock bolt ، Roof convergence ، Rock engineering system (RES) ، Multi-option RES-based model ، Underground coal mines