| Fully mechanized top-coal caving mining method which is used widely in the world exists for many years. Especially in recent year it was developed rapidly in our country.Jining3 coal mine which is berried deeply is a modern typical mine of overcoming in production with fully mechanized top-coal caving mining method. It extracts the third coal layer safely and efficiently and achieves advanced fruit in the world because of employing the experiences of other mines of Yanzhou coal corporation. This paper is a summary of study of "strata movement and rock pressure control" which is a foundation study and carried out to avoid heavy accidents and environmental disasters in extracting the third coal layer. The fruits of this paper comprise three parts as following:The first part: law of overburden movement and the forecast and control of correlative accidents in extracting the third coal layer with fully mechanized top-coal caving mining method.This part summarizes the basic law of overburden movement when the coal being extracted generally including the thickness of immediate roof, the scope of water flowing fractured zone and the relationship with mine conditions such as shear height , length of working face.This part further studied the reasons, conditions and the control methods of accidents took place in the fully mechanized top-coal caving working face and perfected the control and decision-making model of accidents. It provides the content to develop software and the whole system which is foundation for us to achieve information form, intelligence and video in the decision of control accidents in our working faces.The second part: Study of the development and change law of abutment pressure attribution and the control of response accidents of the third coal layer in Jining 3 mine.In this part base on the study of abutment pressure attribution model of structure mechanics and mathematics, and assistant of the study of three dimensional similar material simulation and mathematical calculation. This part generally study the relationship between influencing factors such as bearing depth, shear height, thickness of coal, and face length and the abutment pressure, attribution in the third coal layer. By mathematical calculation, find outthat when length of working face, coal seam thickness and coal depth are not changed, the relation between abutment pressure coefficient and working face driving distance is:y = yo+A] 1-exp -^ I .The third part: Dynamics of forecast and control subsidence of the third coal layer in Jining 3 mine.This part based on the field measurement especially dynamic observation with GPS, studied law of surface subsidence movement and development in 6301 working face and relationship with overburden movement. It indicates that the fracture height decided by face length decide speed and finally depth of the surface subsidence. The site and time of surface subsidence appearance and the law of subsidence speed is decided by rock fracture movement including the processes of the first movement and the circle movement of rock. The fruit brings the forecast of surface subsidence occurs to a high level.Based on study fruit of the first working face subsidence field measurement and abutment attribution, the paper successfully established the model of structural mechanics and mathematical model. The models correctly express the influence factors such as mining depth, working face length and shear height, and the law that subsidence value becomes little and settlement area becomes big with the increase of mining depth in the same working face length.According to the model of structural mechanics and mathematical model, deduce |
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