PREDICTION OF UNCONFINED COMPRESSIVE STRENGTH OF ROCKS BY POINT LOAD STRENGTH INDEX

Abstract

The point load testing is widely used to determine rock strength indeces in geotechnical practices as a result to simplicity. The present study presents correlation equations between the unconfined compressive strength (q u) and point load strength index Is (50) adopted for different types of rocks. In order to estimate a new correlation between the unconfined compressive strength and point load strength test, more than 166 tests were performed. The tests were conducted on four rock types including Sandstone, Siltstone, Limestone and Basalt. The soil samples were collected from different sites along the new administrative capital of egypt. The study shows a reliable correlation between the unconfined compressive strength estimated from the two test approaches.