DIRECT SHEAR TEST ON ROCKS

Abstract

The characteristics of strength in shear is widely used in -problems of rock mechanics, therefore, it becomes of utmost importance to determine the shear strength of a rock mass. The study was carried on six type of rooks using two different methods and it was found that oblique shear test gives shear strength envelope very close to that obtained from direct shear test. The teat data was analysed and suitable correlation between shear strength and normal stress was obtained. It was found that actual shear strength envelope is nonlinear for all rocks, but residual shear strength envelope was found to be linear. A new method has also been developed for determining the residual shear strength parameters which gives residual angle of internal friction quite close to that obtained from direct shear test on solid rock samples.