Central Soil and Materials Research Station, New Delhi, India
Online published on 16 June, 2021.
Shear strength parameters of concrete-rock and rock-rock interfaces are required for checking dam sliding and rock slope stability respectively. In-situ shear tests are commonly used to assess the shear strength parameters of rock mass. In the present paper, results of in-situ shear tests conducted at one of-the dam site in Himachal Pradesh are discussed. This study was conducted to obtain parameters ‘c’ and θ on concrete-rock and rock-rock interface from in-situ shear test on quartzite rock mass. The results of 12 concrete-rock and 8 rock-rock tests conducted in both bank drifts were analysed in detail to obtain critical shear strength parameters. Study revealed that concrete-rock interface has two types of failure modes, i.e. (i) failure along jointed rock-concrete interface; (ii) foliation joint-concrete interface and shear strength parameters were determined for both modes. Tests results on rock-rock interface were obtained by combined plotting of shear stress and normal stress obtained in both banks. Shear strength of concrete-foliation joint interface is found to be lowest among three shear strength parameters determined and-suggested to use in the dam sliding stability. Shear strength parameter of Quartzite rock mass obtained-at the site is the lowest when compared to values reported by Singh (2009) and Dhawan (2015).
In-situ Shear Test, Quartzite rock mass, Dam sliding stability, Foliation joint
