Simulation Analysis on the Strength and Acoustic Emission Characteristics of Jointed Rock Mass

Original scientific paper To analyse the influence of joint angle, number and spacing on the strength and acoustic emission (AE) characteristics of rock mass, the uniaxial compression model of rock specimens was established using the micro particle flow PFC2D software platform. The intact rock parameters were determined via trial and error, joints with different angles, numbers and spacing were prefabricated in the model, and a compression test was performed using the displacement control method. The compressive strength, elastic modulus, and AE time characteristics of the rock specimens increased, decreased, and then increased again along with increasing joint angle. The AE characteristics at joint angles 0°, 15°, 30° and 90° were consistent with those of the intact rock specimens, while the 45° ÷ 75° joint angle showed relatively discrete AE characteristics. A larger number of joints corresponded to lower uniaxial compressive strength, elastic modulus, and AE intensity. However, the time and strain range of the obvious AE were not significant. The compressive strength and AE signal intensity of the rock specimens increased along with joint spacing, but the AE triggering time did not show obvious changes. Uniaxial compression tests were performed via numerical simulation to avoid the non-homogeneous and discrete effects from the indoor test and to reflect accurately the influence of joint angle, number, and spacing on the strength and AE characteristics of rock mass. The results can help in generating reliable criteria for predicting the instability of engineering rock mass.