Research On The Stability And Support Parameter Of Tunnel In Barrier Pillar Stoping Of Dongguashan Copper Mines

After the deep mining, problems about the stability of tunnel have become increasingly significant. In terms of the theoretical analysis, the field measurement and numerical simulation, this thesis makes a study on the stability of the tunnel in barrier pillars stoping of Dongguashan copper mines as follows.(1) By consulting a great number of literature materials, the author systematically summarizes analytical methods for the stability of tunnel, the tunnel supporting theory, the current situation of the tunnel supporting technologies and its research achievements. Moreover, the author also puts forward problems existing in the current study and research ideas and contents of this thesis.(2) On the basis of the actual situation of the tunnel in barrier pillars stoping of Dongguashan copper mines, this thesis studies on the feasibility to apply the supporting theory for the broken rock zone into the design of the tunnel support for barrier pillars in Dongguashan. Moreover, with the premise that the mechanical model for the broken rock zone around the tunnel of the barrier pillars, this thesis analyzes load-carrying capacities of surrounding rocks in different stressed zones within the scope of the broken rock zones for the surrounding rocks in the barrier pillars and derives a formula for the radius of the broken rock zone. Based on the theoretical formula that has been derived for the broken rock zone in the barrier pillar, it can be known that the range of the broken rock zone in barrier pillars is1.46m.(3) Simulating the tunnels of the barrier pillars by the FLAC3D as numerical simulation software, this thesis concludes that a plastic zone covering an area of1.6m-2.2m is formed around the tunnel of barrier pillars. The plastic zone has the greatest scope when the roof is in the450area and in the base angle. In accordance with the maximum principal stress, the minimum principal stress and the shift diagram, it can be seen that once damaged, the tunnels for barrier pillars need support to maintain its own stability. Spandrels, the base angle, the middle of the stalk are easily damaged for tunnels. Therefore, these places needs more support. (4) In line with research results for the stability of the tunnel in barrier pillars stoping and the actual situation of the barrier pillars, a plan is made to test the broken rock zone for tunnels in barrier pillars. The sonic apparatus RSM-SY5is used to test the broken rock zone. By analyzing the test results, the author concludes that the broken rock zone for tunnels stoping barrier pillars ranges from0.8m to1.3m, as a medium rock zone.(5) According to different results from numerical simulations for the supporting plans of tunnels in barrier pillars stoping of Dongguashan, parameters for the supporting plan is optimized. Moreover, based on a comparative analysis of the supporting effects of different supporting plans, the optimal supporting plan is identified, thus guiding the supporting design for the tunnels in barrier pillars.Research achievements in this thesis are of great reference value for the stability of the tunnels stoping barrier pillars in the third step. In this...