IN SITU AND LABORATORY TESTS ON ROCKS FOR UNDERGROUND STRUCTURES

Abstract

The design engineer in Rock Mechanics is confronted with rock as a rockmass, which is an assemblage of regular or irregular blocks of rock material separated by structural features such as bedding planes, joints, fisSures, cavities and other discontinuities. Consequently, when dealing with rocks, the engineering properties of both intact rock and rock masses must be considered. Curing design process of an underground structure, laboratory tests on intact rock and insitu tests on rockmass become essential. Although impressive progress has been made in the field of Rock Mechanics, particularly in the last two decades, there is a need to assess and verify the applicability of different rockmass classification_systems and various correlations developed in context with Indian rocks. In this study, a number of insitu and laboratory tests were conducted on different types of rocks found in Himalayan region to verify the following correlations : 1. Correlation between and Rock Mass Rating Modulus Reduction Factor 2. Correlation between Elastic Modulus and Rock Mass Rating 3. Correlation between Static Modulus of Elasticity and Dynamic Modulus material of Elasticity of rock (vi) 4. Correlation between Compressive Strength and Schmidt Hammer Rebound Values and unit weight of rock material 5. Correlation between Point Load Strength Index and Uniaxial Compressive Strength of rock material The above correlations developed on the basis of test data may prove useful to engineers involved in design, construction and planning of underground structures pertain-ing to different hydroelectric projects in Himalayan region