As an important mechanical index of rocks

brittleness is of great significance for deep rock mass behavior assessment and disaster prevention. The stress-strain curve of rock can well represent rock brittleness. Considering that most of the existing brittleness indicators based on stress-strain curves only analyze a part of the curve

and few indices can be accurately applied to the rock II type curve

lack of overall consideration may lead to the inadequate adaptability and reliability in engineering application. In order to solve those problems

such as the unclear physical meaning and the discontinuous relationship between the evaluation results and rock brittleness of the existing brittleness indices based on the complete stress-strain curve of rock

the influences of pre-peak stress rising rate

post-peak stress falling rate and peak strain on rock brittleness were analyzed

and a method of rock brittleness index with clear physical meaning

monotonous and continuous relationship between calculation results and rock brittleness was proposed. The commonly used brittleness indices were selected to compare the brittleness evaluation of the marble of Jinping II hydropower station and the granite

metamorphic sandstone and gneiss of a railway under uniaxial compression conditions

which verified the applicability of the index proposed. This novel brittleness index was further applied to the brittleness evaluation of marble under conventional triaxial test conditions. The results showed that this index could not only quantify and classify the brittleness characteristics of different rock types

but also characterize the confining pressure inhibition behaviors of rock brittleness.