Predicting uniaxial compressive strength by point load test: Significance of cone penetration

The point load test method was introduced for predicting uniaxial compressive strength (UCS), which has significance of cone penetration. The study examines the accurate measurement of distance (Df) improves the reliability of point load strength index in predicting UCS. The changes and magnitudes of cone penetration were observed with weathering in granitic specimens, and the significance of these changes on the performance of point load test to consistently produce a smaller band of scatter, and improve prediction of UCS and the weathering grade. The common standards, ISRM and ASTM, indicate that the cone penetration depth should be considered in determining load strength index (Is(50)) particularly for weak rocks. The accurate measurement of cone penetration depth revealed that deeper penetration occurs in stronger rocks and the scatter in the data is minimized leading to a significantly better regression coefficient in predicting UCS.