نوع مقاله : مقاله پژوهشی
1 دانشیار گروه مهندسی معدن دانشگاه بین المللی امام خمینی(ره)
2 کارشناسی مهندسی معدن دانشگاه بین المللی امام خمینی(ره)
عنوان مقاله [English]
Brittleness is one of the most important inherent properties of rock which has a great effect on behavior of rock during various operations. For the time being, there is no standard method available for direct measurement of rock brittleness. So, different empirical relations and indirect methods have been provided by researchers to determine rock brittleness. Although the results are very different, but all of the methods suggest that rock brittleness is a function of strength (tensile strength and uniaxial compressive strength). This investigation has used initial data obtained from the tests on samples of Karaj Tuff rock and studied the relationship between point load index and concept of brittleness for this kind of rock. Most of the published literatures on the field of brittleness indicate that has been used three concepts to determine this index; including B1 (ratio of uniaxial compressive strength to tensile strength), B2 (ratio of the difference of uniaxial compressive strength and tensile strength to the sum of uniaxial compressive strength and tensile strength) and B3 (ratio of the multiplication of uniaxial compressive strength and tensile strength divided by two). The relationship between these three concepts and point load index is investigated for dry state using coefficient of determination analysis (R2). The results indicate that the highest value for coefficient of determination is achieved from Is(50)- B3; Also, Only a second order equation can reveal the relationship between the values of brittleness and point load index.