| The movement law of top-coal and behavior of rock pressure regularity under the sub-level caving in extremely soft seam of steep coal mine is defferent from genty inclined coal.Physical the geometric characteristics and spatial and temporal relations,dynamic disaster is very likely to be induced by the such complexity conditions of the top coal.In this study, engineering background is hydraulic prop supporting face caving coal feasibility and key technology research for the sub-level caving in extremely soft seam of steep coal mine.A combination of research methods of using damage theory analysis,underground pressur site monitoring,numerical simulation analysi and so on, synthesis of steep seam (35°) during top coal caving mining the pressure distribution of the roof and the top-coal movement patterns as well as effects of hydraulic prop supporting research.Have coal and rock damage constitutive equations by using of damage theory, analyzed the variation of bearing pressure and the influencing factors, solved the working face of the support resistance at different locations. The research results show the basic mining pressure parametersand characteristics,and roadway surrounding rock deformation characteristics,the working resistance of individual hydraulic-prop,dynamic load factor and so on , category of direct roof,grade of the old roof. Analysis the movement laws of the roof and the top-coal by observing the deep base point displacemen and further understanding the top-coal from the entities coal to crack development, linking, broken mechanism. With the constitutive model in FLAC3D,numerical simulations were carried out that stress and displacement have been effectively controlled,and pointed out the focus of attention to protection.The above results provide basis for the hydraulic prop supporting face caving coal feasibility and key technology research for the sub-level caving in extremely soft seam in steep coal mine...
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