The Tunnel Instability Analysis Of Deep Mining And Parameter Optimization Of Bolting

The tunnel instability of deep mining in metal mines has increasingly become one of the main problems troubling normal production of mine. According to the tunnel instability problem of deep mining in Dongguashan Copper mine in this paper, the method including theoretical analysis, numerical simulation and on-site investigation was comprehensively used, the tunnel stability of deep underground mining in high stress condition and response characteristics of tunnel under dynamic load were analyzed, the instable laws of deep tunnel in different stress conditions were further studied, the supporting program of deep tunnel was proposed and the support parameters were optimized. Main research contents are as follows:(1) The surrounding rock stability of deep tunnel in different tectonic stress field was simulated through numerical analysis software Flac3D, the influence of vertical and horizontal stress to tunnel stability in deep tectonic stress field was analyzed, and the basic law of tunnel instability was preliminarily reached;(2) The influence of peak stress of dynamic load and variations of disturbance frequency in deep tectonic stress field to tunnel stability under different static pressure was studied through numerical analysis software Flac3D;(3)The failure process of deep rock tunnel in static load was analyzed by RFPA, the whole process of crack initiation, expansion up to run through destruction under tectonic stress field was studied from micro-perspective, which provided a reliable basis for selecting and confirming of bolting program;(4)Combined with specific practice of Dongguashan copper mine on the base of above research, bolting parameters of tunnel were calculated from theoretical calculation including the suspension theory, loose ring theory and engineering analogy method, and the bolting program was proposed and the support parameters were optimized, which provided a reliable basis for tunnel bolting. Closely combining with the engineering practice in the paper, the failure and instability mechanism of deep tunnel were deeply studied by numerical simulation software, which laid the foundation for bolting of deep tunnel, had relatively important theoretical and engineering application value.