STUDY OF UNIAXIAL COMPRESSION STRENGTH AND ELASTIC CONSTANTS OF ROCK AND THEIR CORRELATION

Abstract

The foundation of any structure, viz, a dam, a bridge a multistoried building etc. should rest on rock which Is considered to be the most s1tisf,,ctory material, Some of the relatively recent failures of dams founded on rocks, such as M alpasset Dam in 1959 and the Vajont Darn in 1963, hnve forced the Engineers to study the rock properties with respect to engineering aspects and design of structures. The most important properties needed are the uni.-xial compressive strength and deformation ch;,ricterStics. For determination of deformritions a knowledge of modulus of elasticity and poissLn's ratio is essential. The usual methods for determining the uni;-xial compressive strength of rocks require prepf.r~tion of test specimens in the form of cylinders or cubes. The preparrtion of the s;me require use of dinmond Saws -Ind diamond drilling equipment, which are expensive. Hence evaluation of unioxiel compressive strength from irregular lumps would be economical, quick, if the good correlation exists. Fact44s effecting the uniixial compressive strength Pnd elastic constants of rocks are mostly same. Therefore a relation between uniaxia_l compression strength and el;nstic const-nts must exist. Six type o ' rocks were obtained• from different parts of U.P. In the laborrtory their lump strength, cube strength, cylinder strength in compression and modulus of elasticity and poisson's ratio were determined. An attempt has been made to develop corre1.itinn'of uni axial compression strength with irrgulnr 1um~nnd cube strength, Correlations between modulus of elnsticity,uni-xipl compression strength and poisson's ratio have also been obtained, Nomograms have also been developed in some cases for ensy prediction of modulus of elasticity & uniaxial compression strength.