POINT LOAD STRENGTH INDEX OF ROCKS

Abstract

The uniaxial compressive strength of .cocks could be predicted with reasonable accuracy from recpntly developed tPoint Load Strength Index? tests; which are economical quick, simple and require less number of test specimens. A new portable apparatus has therefore been designed and fabricated on th- basis of B ieniaws ki (1974) ' s apparatus. This apparatus has performed excellently during the present series of 200 tests. The fourteen type of rocks which are soft to hard, homogeneous to foliated, fresh to highly weathered, sedimentary, metamorphic and ignious were used in t~sts. Both uniaxial compression tests qc and point load strength tests Is, have been conducted for various Was sizes and length of cores. The test data/analysed and a correlation that qc = 22 Is (50) , where Is(50) is the corrected value of point load strength index for a standard core diameter of 50 mm was determined. However this corre-lation was not found to be applicable in case of weathered rocks. It is recommended that this test should be standar-dized by Indian' Standard Institute for popularising the test in India.