Permeability of carbonate rocks of the Chandragiri limestone using discontinuity analysis and rock mass classification system, central Nepal

Document Type : Research Paper

Authors

Central Department of Geology, Tribhuvan University, Nepal.

10.22059/ijmge.2026.380823.595187

Abstract

The purpose of this study was to understand rock mass characteristics of carbonate rocks using parameters of RMR and GSI and their bearing on effective porosity or permeability of rocks, which is the crucial entity in the flow and storage of water within a rock mass, which is an important consideration in groundwater investigations. Discontinuity analysis is a technique that describes the geometry and characteristics of joints and fractures in a mass of rock. The carbonate rocks of the Chandragiri Limestone of the Phulchauki Group were assessed for strength, joint volume, spacing, joint conditions, and groundwater. Many researchers use the combined condition value of the Lugeon and the RQD value to develop the empirical relation to estimating them. The maximum RMR (77.50%) and the lowest RMR (51.75%) indicate good to fair rock mass. GSI computed based on structural rating and surface condition rating falls between 33 and 55, indicating a blocky, disturbed structure with a fair to very good surface. GSI* computed using the joint condition and RQD (using empirical equation) falls between 42.53 and 73.85, showing somewhat different results. The rock mass permeability (from RQD) varies from 2 to 8.78, indicating a range from slightly permeable to permeable. The RMR-GSI charts were used to evaluate the permeability of the rock mass, which also indicates slightly permeable to permeable rock mass. The permeability (Lugeon) is more than 100 for all locations classified as very high, indicating the rock is permeable.

Keywords

Main Subjects

References

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International Journal of Mining and Geo-Engineering
Volume 60, Issue 1
March 2026
Pages 83-90

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