An assessment on the correlations between uniaxial compression strength and point load index


ARABIAN JOURNAL OF GEOSCIENCES, vol.15, no.3, 2022 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 15 Issue: 3
  • Publication Date: 2022
  • Doi Number: 10.1007/s12517-021-09391-3
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Agricultural & Environmental Science Database, Aquatic Science & Fisheries Abstracts (ASFA), Geobase, INSPEC
  • Keywords: Point load strength index, Uniaxial compressive strength, Regression analysis, Performance analysis, FUZZY INFERENCE SYSTEM, GRANITIC-ROCKS, ENGINEERING PROPERTIES, PYROCLASTIC ROCKS, PREDICTION, POROSITY, MODEL, TENSILE, SIZE, SANDSTONES
  • Eskisehir Osmangazi University Affiliated: Yes


Point load index (Is) has been commonly used for predicting uniaxial compressive strength of intact rocks (UCS) because Is is easy and quick test performed on lump specimens. For this reason, many empirical equations in the literature to estimate the uniaxial compressive strength from the point load index have been proposed for the last five decades. In this study, the performances of the existing empirical equations are assessed employing the results of 55 uniaxial compressive tests and point load tests from geotechnical studies of Ayas Tunnel (Ankara, Turkey) and Lamas Dam (Mersin, Turkey), and an empirical equation is proposed. Performances of 40 empirical equations in the literature are assessed with these data. Simple regression analyses performed between measured UCS values and estimated UCS values. The coefficients of determinations obtained in this study are insufficient for the determination of performance of empirical equations. Additional performance analyses were performed with RMSE, VAF, MAPE, and prediction performance. According to results of the performance analyses, 8 of the 40 empirical equations showed acceptable performance.