Modified RMR to determine rock mass quality, study case of diversion tunnel in Meninting Dam, West Nusa Tenggara, Indonesia

The Meninting Dam under construction on Lombok Island, West Nusa Tenggara, Indonesia, requires a good planning to build diversion tunnel support its development and mobilization. is planned be built through rocks with medium poor rock mass quality. stage involves various parameters, i.e., the classification, using either RMR or GSI method. Converting values from one method another makes work easier. However, constraints found were limitations of observational data, such as discontinuity conditions. objective this article discuss alternative depiction conditions in An equation was developed obtain prediction model for determining value, based data. evaluation showed that mathematical models research had small gap error compared other values. then can used predict value data vice versa, higher degree accuracy precision according actual surface conditions, especially site at Dam.