A Correlation-Regression Statistics: Predicting Uniaxial Compressive Strength from Point Load Index for Hydrothermal Clay Materials

Muhammad Alfiza Farhan; Akbar Aprian

doi:10.31315/jtp.v11i2.16036

Authors

Muhammad Alfiza Farhan Institut Teknologi Sains Bandung
Akbar Aprian Institut Teknologi Sumatera

DOI:

https://doi.org/10.31315/jtp.v11i2.16036

Keywords:

Uniaxial compressive strength, Point load index, Hydrothermal alteration, Rock strength characterization

Abstract

This study addressed the difficulty of determining uniaxial compressive strength in hydrothermally altered breccia, where preparing intact core samples was not feasible. A field-based approach using point load index measurements was adopted to provide an alternative means of estimating rock strength. Twenty-one representative breccia samples from Pit C were tested through standardized point load procedures and laboratory uniaxial compression tests. Linear regression analysis was performed to examine the relationship between the two strength parameters. The results showed a strong and statistically significant linear trend, indicating that point load index values could reliably predict uniaxial compressive strength for the altered breccia. The analysis further demonstrated that most strength variability was explained by the regression model. These findings supported the use of point load testing as an efficient and practical method for strength estimation in geological conditions where conventional testing was limited.

References

Adriansyah, Y., Krisnantara, G., & Setiadi, K. (2021). Korelasi point load index dan uniaxial compressive strength pada satuan batupasir dan batulempung Formasi Latih untuk penentuan koefisien kekuatan batuan di Pit X Tambang Batubara PT Berau Coal. Jurnal Geomine, 2(2), 9–16.

Agustawijaya, D. S. (2007). Mechanical characteristics of volcanic rocks in Indonesia. Engineering Geology, 90(1–2), 27–37.

Basu, A., & Aydin, A. (2006). A method for obtaining the point load strength index. International Journal of Rock Mechanics and Mining Sciences, 43(3), 399–415.

Bieniawski, Z. T. (1975). The point-load test in geotechnical practice. Engineering Geology, 9(1), 1–11.

Broch, E., & Franklin, J. A. (1972). The point-load strength test. International Journal of Rock Mechanics and Mining Sciences, 9(6), 669–697.

Hoek, E., & Bray, J. (1981). Rock slope engineering (3rd ed.). Institution of Mining and Metallurgy.

Hawkins, A. B. (1998). Aspects of rock strength. Bulletin of Engineering Geology and the Environment, 57, 17–30.

ISRM. (1981). Rock characterization, testing and monitoring: ISRM suggested methods (E. T. Brown, Ed.). Pergamon Press.

ISRM. (1985). Suggested methods for determining point load strength. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 22(2), 51–60.

Jamshidi, A. (2022). A comparative study of point load index test procedures in predicting the uniaxial compressive strength of sandstones. Rock Mechanics and Rock Engineering, 55(10), 4507–4516.

Jamshidi, A., & Sousa, L. R. (2023). Correlation between point load index and uniaxial compressive strength: A state-of-the-art review. Geotechnical and Geological Engineering, 41, 1965–1987.

Jamshidi, A., & Sousa, L. (2024). Accuracy of point load index and Brazilian tensile strength in predicting the uniaxial compressive strength of rocks: A comparative study. Materials, 17(20), 5081.

Kahfi, M. Z. (2021). Analisis awal pendugaan nilai UCS dari nilai PLI untuk batu lempung dan batu pasir, PT Arutmin Indonesia Tambang Asam Asam, Kalimantan Selatan. In Prosiding Temu Profesi Tahunan (TPT) PERHAPI XXX dan Kongres XI (pp. 1–8).

Kohno, M., & Maeda, H. (2012). Relationship between point load strength index and uniaxial compressive strength of hydrothermally altered soft rocks. Geomaterials, 2(4), 85–91.

Kohno, M., & Maeda, H. (2012). Estimation of uniaxial compressive strength of soft rock based on point load index. Japan Geotechnical Society Special Publication, 7(1), 71–80.

Kohno, M., & Maeda, H. (2018). Influence of moisture conditions on point load index and UCS of hydrothermally altered soft volcanic rocks. Japan Geotechnical Journal, 13(1), 123–135.

Kolapo, P., & Munemo, P. (2021). Investigating the correlations between point load strength index, uniaxial compressive strength, and Brazilian tensile strength of sandstones: A case study of QwaQwa sandstone deposit. International Journal of Mining and Mineral Engineering, 12(1), 67–83.

PT Bumi Suksesindo. (2024). Point load test Pit C RL 135 Block 6 & 8: Sampling location and results. PT Bumi Suksesindo.

Rai, M. A., Kramadibrata, S., & Wattimena, R. K. (2014). Mekanika batuan. Institut Teknologi Bandung.

Sadeghi, E., Nikudel, M. R., Khamehchiyan, M., & Kavussi, A. (2022). Estimation of unconfined compressive strength of carbonate rocks by index tests and specimen size properties: Central Alborz Zone of Iran. Rock Mechanics and Rock Engineering, 55(2), 125–145.

Schrier, B. (1988). Correlation of point-load index with compressive strength for brecciated igneous rocks. Unpublished report cited in literature.

Supandi, S. M. (2022). Mekanika batuan. Mega Press.

Tsiambaos, G., & Sabatakakis, N. (2004). Considerations on strength of intact sedimentary rocks. Engineering Geology, 72, 261–273.

Wang, J., Yang, Y., Tan, Z., Li, D., & Liu, Q. (2022). Correction of point load strength on irregular carbonaceous slate in the Luang Prabang suture zone and prediction of uniaxial compressive strength. Applied Sciences, 12(18), 9147.

Wong, L. N. Y., Maruvanchery, V., & Liu, G. (2017). Strength of volcanic rock lumps using point load tests. Engineering Geology, 226, 236–244.