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1. Seismic Investigation on Characteristic of Overlying Strata Movement in Unsymmetrical Isolated Longwall Mining | |||
LIU Zhangli,MU Zonglong,DOU Linming,CAO Anye | |||
Mine Engineering and Technology 14 October 2011 | |||
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Abstract:Based on the key stratum theory, overlying strata structures above a typical unsymmetrical isolated face (LW10302) is analyzed, and a microseismic monitoring is also applied to characterize the fracturing propagations associated with overburden movement in mining progress. The results show that the overlying strata above LW10302 can be divided into key strata of different grades, and the formed "O-X" fracturing structure have the main and inferior "O-X" ones. The spatial evolution of seismic events demonstrated that seismic activities fits very well with the overburden fracturing patterns and stress manifestation around the longwall face. In the mining process, most of the events located within the surrounding strata of LW10301 and 10302 while low energy events distributed mainly in multiple roof and floor strata, and the strong tremors occurred almost within the super-thick primary key strata and appeared to be related to shear fracturing of large-scale overburden movement. Additionally, seismic signals corresponding to different failure mechanisms show different characteristics in waveform features. The study in this paper indicates that microseismic monitoring can provide invaluable information to characterize the mining-induced seismicity and reveal the failure patterns within strata associated with mining, which will greatly benefit the alleviation and prevention of rock burst hazards in mines. | |||
TO cite this article:LIU Zhangli,MU Zonglong,DOU Linming, et al. Seismic Investigation on Characteristic of Overlying Strata Movement in Unsymmetrical Isolated Longwall Mining[OL].[14 October 2011] http://en.paper.edu.cn/en_releasepaper/content/4445454 |
2. A Particle Swarm Optimization Based Grey Forecast Model of Underground Pressure for Working Surface | |||
Ma Dan,Peng Yan | |||
Mine Engineering and Technology 29 October 2010 | |||
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Abstract:Forecasting of underground pressure for working surface (UPWS) plays an important role in mining technology industry for safety production. The characteristics of UPWS include roof lithologic, mining height of coal seam, geological structure, mining depth, promoting speed of working surface, influence of mining, etc. These factors directly affect the difficulty of forecasting trends in this field. This paper presents a new parameter optimization scheme of grey model (GM) using the particle swarm optimization (PSO) algorithm. The production coefficient of the background value is considered as decision variables and the forecasting mean absolute percentage error is taken as the optimization objective. Parameter optimization of GM is formulated as the combinatorial optimization problem and would be solved collectively using PSO technique. The model can be optimized once the PSO finds the optimal parameters of GM. GM with this parameter optimization algorithm is then applied in UPWS forecasting. Results of short and long terms forecasting show that PSO is an effective global optimization algorithm suitable for the parameter optimization of GM. The authors discuss implications of these findings for theory and practice. | |||
TO cite this article:Ma Dan,Peng Yan. A Particle Swarm Optimization Based Grey Forecast Model of Underground Pressure for Working Surface[OL].[29 October 2010] http://en.paper.edu.cn/en_releasepaper/content/4389830 |
3. Numerical simulation of coal seam joints and stiffness effects on coal bumps | |||
Jiang Yaodong,Zhao Yixin,Zhu Jie | |||
Mine Engineering and Technology 23 March 2006 | |||
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Abstract:The numerical approach to translatory coal bumps analysis is used to examine the effects of joint and coal seam stiffness on the outburst velocity, deformation magnitude of the opening wall and plastic zone length in the coal seam. A series of tests are performed by varying the joint dip angles, spacing normal to joint tracks, joint block size and coal seam stiffness ratio to the surrounding rock. Results of joint and coal seam stiffness effects analysis indicate that joint dip angle, interval spacing, block size and coal seam stiffness ratio have profound influences on coal bumps. The increasing of interval spacing and joint block size can generate larger roadway deformation, lower roadway deformation velocity and longer plastic region in the coal seam. Higher stiffness ratio can also result in larger deformation, higher deformation velocity of opening wall. Coal bumps conditions deteriorate as the dip angle rotated to 90 degree or the elastic zones disappear in the whole active zone of coal seam for different spacing distributions. | |||
TO cite this article:Jiang Yaodong,Zhao Yixin,Zhu Jie . Numerical simulation of coal seam joints and stiffness effects on coal bumps[OL].[23 March 2006] http://en.paper.edu.cn/en_releasepaper/content/5876 |
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