| Orepass transportation has the advantage of low cost, high passing capacity, etc. It is widely used in underground mine, responsible for most of the ore waste rock transport tasks, deemed as the throat of mine.Impacted by ore unload and blasting action when removing the pass blocks, orepass often damage before service life. Repair of damaged orepass needs to enter the inside of it, so the stability analysis and safety research of the wall rock has actual engineering requirement.This paper regards the main orepass and main waste chute of Dahongshan Copper Mine as the research object, the main research contents and conclusions are as follows:(1) Collating datum, fully understand the status of chute. The main orepass and main waste chute of Dahongshan Copper Mine arranged symmetrically, multiple site transfixion with haulage roadway was exist in-550m and-535m level before restoration.The size of rock pillar between two chutes changed from more than20m when they were built to the most weaknesses7m. In vertical direction chute shape is big in the middle but is small at both ends,and in horizontal direction collapse expands in all directions, impacted side is most serious, followed by discharge side and remaining areas. In general, orepass and waste chute show the similar shape, the factors of local differences are lithology, geological structure, throughput of ore and waste, etc.(2) Determination of rock mechanics parameters. Based on the rock mechanics data and structural plane geological investigation of orepass wall, using Hoke-Brown formula to estimate results.(3) Determination of lateral pressure coefficient and comparison of the analysis method and simulation method. Lateral pressure coefficient obtained by the actual measurement data of ground stress. After compared with the data calculated by Anaheim hypothesis and Kinnick hypothesis, the ground stress of Dahongshan Copper Mine is the interaction of gravity stress and tectonic stress, mainly is horizontal stress. Therefore, fixed displacement boundary to generate initial stress is not adopted for numerical simulation.(4) Stability analysis and simulation of main orepass wall. Used FLAC3D for calculation of main orepass wall stability on the basis of mechanics parameter of adjoining rock and ground stress data. Analysis from the stress concentration and plastic zone shows that unstable region located in the rock pillar between the two chutes and the offside of it. The orepass wall have to take safety measures before enter to construction.(5) Simulation verification for supporting effect. makes equivalent computation on mechanics parameters of surrounding rock after supporting using empirical formula,and then make a computer simulate calculation for the safe handling surrounding rock.The results show that with the combined effect of anchors-gunite-web shoring and special support,surrounding rock mass status was reinforcement.Area of the focus of reinforcement is shown and have a brief introduction to construction technological process of main chute of Dahongshan Copper Mine. |
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