1Central Soil and Materials Research Station, New Delhi
Online Published on 13 April, 2023.
In-situ shear tests in rock mass are mainly required for stability analysis of dam, bridges, slopes and numerical modelling of underground structures for river valley projects. The test gives shear strength parameters in terms of cohesion ‘c’ and friction angle ‘ϕ’ of rock mass. In the present study, in-situ direct shear test data of 39 projects from India and neighbouring countries have been taken into account for analysis where metamorphic rock was encountered. Test results were classified and analysed on the basis of rock types for different grade of metamorphic rock. The analysis and interpretations of this study suggests that minute geological variations can have significant effect on the shear strength parameters of the rock mass. It is observed from the analysis of data that with increase in metamorphism grade, the cohesion values increase and friction angle values shows a decreasing trend for both rock-rock and concrete-rock interfaces with few exceptions. Further, range of shear strength parameter for different types of metamorphic rock mass has been proposed, which can be used during the pre-feasibility study.
