Correlation of Bieniawski's RMR and Barton's Q System in the Nepal Himalaya

Rock mass classification systems have become one of the most important and necessary tool for determining the composition and characteristics of a rock mass. Its application in the Nepal Himalaya has been continuous from last few decades especially in hydropower, water supply and recently in road tunnel. Out of several classifications, RMR, Q and GSI system are the most accepted and implemented. Many researchers has published direct connections between the site-specific variables and various rock mass classification approaches that were developed as a result of number of assessments and evaluations. Correlations have been provided by number of authors in the past, therefore understanding the source data is crucial to understanding its reliability. The purpose of this research is to present a novel, precise relationship between RMR, Q and GSI in Nepal Himalaya. For this purpose, the data obtained from 14.91 km tunnel excavation from five different projects in Nepal Himalaya were employed. Using simple regression statistical analysis, it was possible to determine the correlations between the RMR, Q and GSI values as they were derived alongside the headrace tunnel. This paper present logarithmic, linear and logarithmic equation for estimating RMR from Q, GSI from RMR and GSI from Q, respectively.

Automated summary

Rock mass classification systems are essential tools for determining the composition and characteristics of rock masses, and have been widely applied in various projects in the Nepal Himalaya region. Among several classification systems, RMR, Q, and GSI are the most accepted and implemented ones. This research aims to establish precise relationships between RMR, Q, and GSI in Nepal Himalaya using data from tunnel excavations in five different projects. By conducting regression analysis, logarithmic, linear, and logarithmic equations were developed to estimate RMR from Q, GSI from RMR, and GSI from Q, respectively.