Empirical estimation of the uniaxial compressive strength from the point load test in anisotropic rocks (schists and shales)
Article Sidebar
Main Article Content
Abstract
In this paper new empirical relationships are developed between uniaxial compressive strength and point load index Is(50) in anisotropic rocks, particularly in schists and shales. We have used data from 2015 point load tests and 229 uniaxial compressive strength tests performed in anisotropic rocks obtained during various stages of study of Paute-Cardenillo hydroelectric project, located in the eastern slopes of the northern Andes Cordillera (SE Ecuador). We have defined five anisotropic rocks types (schists and shales) for which the mean values of uniaxial compressive strength and point load index were obtained according to their orientation with respect to the planes of anisotropy. Finally, it is found that there is no direct relationship between uniaxial compressive strength and Is(50) so it is unreliable take traditional empirical linear regression models, which do not consider the effect of the planes of anisotropy in rock strength. Therefore, three new empirical relationships that estimate the uniaxial compressive strength from Is(50) in anisotropic rocks are proposed.
Downloads
Metrics
Article Details
This work is licensed under a Creative Commons Attribution 4.0 International License.
References
Basu, A., & Kamran, M. (2010). Point load test on schistose rocks and its applicability in predicting uniaxial compressive strength. International Journal of Rock Mechanics and Mining Sciences, (47), 823-828.
Bieniawski, Z.T. (1989). Engineering rock mass classifications. John Wiley, New York, 251 p.
Fener, M., Kahraman, S., Bilgil, A. & Gunaydin, O. (2005): A comparative evaluation of indirect methods to estimate the compressive strength of rocks. Rock Mechanics and Rock Engineering, 38(4), 329-343.
ISRM (1985). Suggested method for determining point load strength. International Journal of Rock Mechanics and Mining Sciences, 22, 51-60.
Ramamurthy, T., Rao, G.V. & Singh, J. (1993). Engineering behavior of phyllites. Engineering Geology, 33, 209–225.
Saroglou, H., Marinos, P. & Tsiambaos, G. (2004). The anisotropic nature of selected metamorphic rocks from Greece. Journal of the South African Institute of Mining and Metallurgy, 104, 215–222.
Tsidzi, K. (1986). A quantitative petrographic characterization of metamorphic rocks. Bulletin of the International Association of Engineering Geology, 33, 3-12.
Vutukuri, V.S., Hossaini, S.M.F. & Foroughi, M.H. (1995). A study of the effect of roughness and inclination of weakness planes on the strength of rock and coal. En: Proc. of Second International Conference on the Mechanics of Jointed and Faulted Rock (H.P. Rossmanith ed.). Taylor and Francis, Balkema, Rotterdam, 151-155.
Zare-Naghadehi, M., Jimenez, R., KhaloKakaie, R. & Jalali, S.M.E. (2011). A probabilistic systems methodology to analyze the importance of factors affecting the stability of rock slopes. Engineering Geology, 118, 82-92.