عنوان مقاله [English]
نویسندگان [English]چکیده [English]
In rock mechanics, determination of stresses on the fracture plane is very important, because instability in a structure such as rock slopes caused by the combination of internal stresses. If limit equilibrium method is used to evaluate the stability, it is necessary to determine normal stresses in the fracture moment to estimate the shear strength parameters. One of the most important experimental criteria for determination of stresses on the fracture plane is Hoek-Brown criterion. In the present paper, efficiency of Hoek-Brown criterion is examined for prediction of stresses on the fracture plane based on the Mohr stress circle which estimates the stresses on the fracture plane according to the real fracture plane. Results show that there are some differences between stresses on the fracture plane obtained by the Hoek –Brown criterion and Mohr stress circle. Therefore, obtained shear strength parameters are depended on of Hoek-Brown envelope. Also, it is inferred that angle of fracture plane obtained using Hoek-Brown envelope differs from the real fracture plane, so the angle is in not a function of real fracture plane but it depends on Hoek-Brown envelope.