Analysis on kinematic behavior of potential large-scale rockfall in the Tanbu limestone open-pit mine in Guangzhou City, Guangdong Province

The Tanbu limestone mine in Guangzhou has been in operation for over 30 years, resulting in the formation of a series of terraced slopes, with the highest reaching approximately 195 m. Between 2012 and 2022, the mining area experienced 26 incidents of slope and dangerous rock body collapses. Recent investigations have identified 16 remaining dangerous rock bodies on these excavated slopes. The risk of slope collapse in this open-pit mine poses a significant threat to ongoing mining operations. Analyzing the collapse behavior of these dangerous rock masses is of great significance for developing effective preventive measures for the collapse of dangerous rock mass in mines. This study focuses on the WY3 and WY11 dangerous rock mass, using Rockfall numerical simulation software. A 1000 kg rockfall was simulated, released from the same starting point 50 times to calculate its fall trajectory, bounce height, kinetic energy, and other related behaviors. The results indicate that over 84% of the falling rocks reached the foot of the slope, with the bounce heights ranging between 5 and 15 m and total kinetic energy between 302.3 and 399.2 kJ. The simulation results closely matched the actual historical paths observed in the study area. The numerical simulation results of these rockfall behaviors based on the Rockfall software provide valuable data to support the identification of rockfall risk zones and the selection of appropriate protective measures. This study also offers a specific case reference for the analysis of rockfall behavior of dangerous rock masses in large open-pit mine slopes.