The efficiency of excavation a mining tunnel is definitely linked with modes of cut-holes. According to experience and methods of engineering analogy, the double-wedge cut, the 9-hole cut and the single spiral cut wer...The efficiency of excavation a mining tunnel is definitely linked with modes of cut-holes. According to experience and methods of engineering analogy, the double-wedge cut, the 9-hole cut and the single spiral cut were determined originally by considering the production conditions and blasting environment of the mining tunnels of the-74 m horizontal in the Da-ye iron mine. Based on acquired modes of cut-holes, the effect of the cut was studied, on the one hand, by a numerical simulation method with the aid of LS-DYNA3D, a nonlinear dynamic finite element program; on the other hand, a spot experiment was carried out in the mining tunnels. Both the numerical simulation and the spot experiment demonstrated and agreed that a single spiral cut provides the optimum excavation effect.展开更多
Coal mine belt fire develops very rapidly and is difficult to control. If not suppressed quickly, a belt fire could easily lead to airflow disorder and undermine the ventilation system. However, belt fire can be preve...Coal mine belt fire develops very rapidly and is difficult to control. If not suppressed quickly, a belt fire could easily lead to airflow disorder and undermine the ventilation system. However, belt fire can be prevented effectively by establishing fire airflow control system. In this work, the 5th belt roadway of Kongzhuang coal mine was taken as the object of investigation, where geometrical models of this roadway were established firstly. Then, based on mathematical model of fire smoke flow, the CO volume fraction, smoke density distribution, air temperature and pollutant velocity vector in the roadway before and after taking airflow control measures were simulated by using Fluent software. It can be known from the simulation that with the normal ventilation status in 5th belt roadway, the countercurrent of smoke does not happen when a fire occurs; the roadway's section is almost filled with CO at 10 m downstream from the fire source, and with air velocity getting stable gradually, the CO concentration reaches about 15 %. After taking airflow control measures, the effect range of temperature field which are harmful to the miners decreases from 69 m to 30 m; and the distance of the roadway fully filled with CO is 5 m farther than that before taking measures. Finally, according to the numerical simulation results and the actual condition of the belt roadway, the warning and automatic remote airflow control system with short-circuit method for the 5th belt roadway was designed to guarantee the safety production.展开更多
By establishing the numerical model in the vertical plane and the similar model in the horizontal plane of gas flow in goaf, the influence of high drainage roadway or drilling on the gas seepage field was analyzed, an...By establishing the numerical model in the vertical plane and the similar model in the horizontal plane of gas flow in goaf, the influence of high drainage roadway or drilling on the gas seepage field was analyzed, and the extraction mechanism was clarified. On this basis, the academic thought of directional long drilling group instead of high drainage roadway was put forward. And then using complex function theory, the permeation mechanical model of drilling group with circle distribution in the mining-induced fracture zone was established to explore the coupling relationship between the drilling quantity, extraction volume and the equivalent extraction rate of single drilling. Finally, combined with the concrete geological production conditions, the main parameters of directional long drilling group were determined. The distance between the drilling group center and the air-return roadway is 24 m, the height is 18 m, and the three drillings are in an approximate equilateral triangle distribution with a space of 8 m. The equivalent extraction square is 4.15 m2. It is shown that the effect of directional long drilling group is evident. The gas content in the upper comer is controlled below 0.95%, the content in the tail roadway is kept below the alarm value, and the content is over 50% in the drill, realizing the secure and effective extraction of coal and gas.展开更多
文摘The efficiency of excavation a mining tunnel is definitely linked with modes of cut-holes. According to experience and methods of engineering analogy, the double-wedge cut, the 9-hole cut and the single spiral cut were determined originally by considering the production conditions and blasting environment of the mining tunnels of the-74 m horizontal in the Da-ye iron mine. Based on acquired modes of cut-holes, the effect of the cut was studied, on the one hand, by a numerical simulation method with the aid of LS-DYNA3D, a nonlinear dynamic finite element program; on the other hand, a spot experiment was carried out in the mining tunnels. Both the numerical simulation and the spot experiment demonstrated and agreed that a single spiral cut provides the optimum excavation effect.
基金Project supported by Joint Innovative Center for Safe and Effective Mining Technology and Equipment of Coal Resources of Shandong Province,ChinaProject supported by Taishan Scholar Program of Shandong Province,China+2 种基金Project(2014JQJH106)supported by Shandong University of Science and Technology Research Fund,ChinaProject(LAK2012-1)supported by Science and Technology Development Program of Safety Production of Shandong Province,ChinaProject(2012ZHTD06)supported by Science Research Innovative Group of College of Mining and Safety Engineering of Shandong University of Science and Technology,China
文摘Coal mine belt fire develops very rapidly and is difficult to control. If not suppressed quickly, a belt fire could easily lead to airflow disorder and undermine the ventilation system. However, belt fire can be prevented effectively by establishing fire airflow control system. In this work, the 5th belt roadway of Kongzhuang coal mine was taken as the object of investigation, where geometrical models of this roadway were established firstly. Then, based on mathematical model of fire smoke flow, the CO volume fraction, smoke density distribution, air temperature and pollutant velocity vector in the roadway before and after taking airflow control measures were simulated by using Fluent software. It can be known from the simulation that with the normal ventilation status in 5th belt roadway, the countercurrent of smoke does not happen when a fire occurs; the roadway's section is almost filled with CO at 10 m downstream from the fire source, and with air velocity getting stable gradually, the CO concentration reaches about 15 %. After taking airflow control measures, the effect range of temperature field which are harmful to the miners decreases from 69 m to 30 m; and the distance of the roadway fully filled with CO is 5 m farther than that before taking measures. Finally, according to the numerical simulation results and the actual condition of the belt roadway, the warning and automatic remote airflow control system with short-circuit method for the 5th belt roadway was designed to guarantee the safety production.
基金Project(50834005) supported by the National Natural Science Foundation of ChinaProject(2010QZ06) supported by the Fundamental Research Funds for the Central Universities of China
文摘By establishing the numerical model in the vertical plane and the similar model in the horizontal plane of gas flow in goaf, the influence of high drainage roadway or drilling on the gas seepage field was analyzed, and the extraction mechanism was clarified. On this basis, the academic thought of directional long drilling group instead of high drainage roadway was put forward. And then using complex function theory, the permeation mechanical model of drilling group with circle distribution in the mining-induced fracture zone was established to explore the coupling relationship between the drilling quantity, extraction volume and the equivalent extraction rate of single drilling. Finally, combined with the concrete geological production conditions, the main parameters of directional long drilling group were determined. The distance between the drilling group center and the air-return roadway is 24 m, the height is 18 m, and the three drillings are in an approximate equilateral triangle distribution with a space of 8 m. The equivalent extraction square is 4.15 m2. It is shown that the effect of directional long drilling group is evident. The gas content in the upper comer is controlled below 0.95%, the content in the tail roadway is kept below the alarm value, and the content is over 50% in the drill, realizing the secure and effective extraction of coal and gas.
