Sliding characteristics of chute waste slag in high steep canyon ecologically sensitive areas

To address the significant ecological impact caused by constructing access roads for tunnel excavation in steep and rugged canyon areas, a novel method is proposed in this paper. This suggests that waste slag materials are rapidly transported through an elongated chute attached to the mountain surface. This study utilizes theoretical analysis, on-site experiments, and numerical simulations to investigate the sliding characteristics of elongated chutes for efficient waste slag disposal. Through theoretical analysis to determine the friction coefficient of the discarded slag in the chute, with the help of field tests to optimize the design of the chute structure, numerical simulation was used to verify the reasonableness of the spacing arrangement of the fishbone-shaped baffle plate. The results reveal the following: (1) Increasing waste slag particle size decreases the waste slag's specific surface area per unit volume, reducing friction between the waste slag and the chute. The sliding speed of waste slag from the bottom opening of the chute gradually increases as the particle size increases. For waste slag particle sizes ranging from 10 to 20 cm, the friction coefficients range from 0.09 to 0.23, with an average of 0.16. (2) The sliding speed of waste slag inversely correlates directly with the length of the chute's zigzag structure and with the angle. Based on on-site experimental results, it is recommended that the zigzag structure length be 2 m and that the angle be set at 120°. (3) As the spacing between the fishbone-shaped baffles inside the chute increases, the force on the individual baffle structures gradually increases. The difference in the resultant force acting on the baffles in the 100 m segment before and after the chute also gradually increases.