The Rock Mass Rating (RMR) system is widely used to assess rock mass quality and the its mechanical parameters including cohesion, internal friction angle, and elasticity modulus. The uniaxial compressive strength (UCS)/point load index (PLI) of intact rock is one of the input parameters in RMR. Rocks in some geotechnical works, such as rock slopes, tunnels, and some foundations are under tensional stresses. In these conditions, the tensile strength of the rocks may be a suitable strength parameter in RMR system to assess mechanical behavior of the rock mass in site a geotechnical work. One of the weaknesses of RMR is that it does not take into account the tensile strength of intact rock. In this paper, a new rock classification is introduced based on Brazilian tensile strength (BTS) as an alternative for point load index (PLI) in RMR. To achieve this purpose, BTS and UCS values for diverse rock types including igneous, sedimentary, and metamorphic were collected through a comprehensive review of existing literature. For each rock type, the correlation equations between BTS and UCS were developed using simple regression analysis. Using data analyses, the intact rock was categorized into seven BTS classes. The BTS classification suggested in the present study can be used as a novel approach in RMR for a rock mass outcropped at the site of a geotechnical project. This can lead to a more comprehensive assessment of the mechanical behavior of the rock mass, and therefore, a more accurate design of a geotechnical project.
Jamshidi,A , Sousa,L and Fereidooni,D . (2026). The Brazilian tensile strength as an alternative for point load index in the Rock Mass Rating system. (e105401). Geopersia, (), e105401 doi: 10.22059/geope.2026.400047.648835
MLA
Jamshidi,A , , Sousa,L , and Fereidooni,D . "The Brazilian tensile strength as an alternative for point load index in the Rock Mass Rating system" .e105401 , Geopersia, , , 2026, e105401. doi: 10.22059/geope.2026.400047.648835
HARVARD
Jamshidi A, Sousa L, Fereidooni D. (2026). 'The Brazilian tensile strength as an alternative for point load index in the Rock Mass Rating system', Geopersia, (), e105401. doi: 10.22059/geope.2026.400047.648835
CHICAGO
A Jamshidi, L Sousa and D Fereidooni, "The Brazilian tensile strength as an alternative for point load index in the Rock Mass Rating system," Geopersia, (2026): e105401, doi: 10.22059/geope.2026.400047.648835
VANCOUVER
Jamshidi A, Sousa L, Fereidooni D. The Brazilian tensile strength as an alternative for point load index in the Rock Mass Rating system. Geopersia. 2026;():e105401. doi: 10.22059/geope.2026.400047.648835