New rock mass classifications for limestone of the Woyla group and its empirical relationship in Aceh Province, Indonesia

The rock mass characteristic study, including RMR89, GSI, and RMR14 and their empirical relationships, had been conducted at ten slopes in Aceh Province, Indonesia. This study aims to determine the RMR89, RMR14 and GSI, as well as develop the empirical relationships among those rock mass classifications especially for limestone of the Woyla group. The scan-line method has been adopted in the collection of RMR and GSI data from the slope faces that consist of geological structures, condition of joints, groundwater, and mechanical parameters of intact rock. The regression analysis was utilised to produce the empirical connection of RMR89 with GSI and new RMR14 by plotting those data in graph and trend-line to produce the empirical relationship. The results revealed that beddings, joints, and minor fault system on the slopes determined the quality of rock mass. RMR89 for limestone in our study area were 58-64 or classified as fair to good, whilst the RMR14 were 61.7-67.7 or categorised as good. The RMR14 were just 1.3-5.7 points higher than RMR89. Besides, GSI value was in the range from 49.3 to 54.1. The empirical correlation between RMR89 and GSI was more likely similar to the previous study; however, the empirical relationship between RMR14 and RMR89 was different and it revealed a lower value compared to other rocks.