Study On Mine Pressure Law Of Fully-Mechanized Stope With Large Inclined Angle And Hard Roof In Medium-Thickness Seam

With the specificity of the sedimentary structure of coal seams and strata, deeply inclined coal seams are characterized by anisotropy, which are different from gently inclined flat seams. In addition, the characteristic related to anisotropy seems to be more obvious as the dip angle increases, and as a result, fully-mechanized mining with deeply inclined coal seam possesses special strata movement law and strata pressure behaviors. The main difference between stope with hard roof and ordinary stope is the distinct strata pressure behavior. Specifically, the strata pressure of the former one is more violent and it is easy to cause impulsion pressure.So far some certain theories and experiment researches relevant to mining technology, roadway surrounding rock control, movement law of overlying strata and strata pressure behavior of deeply inclined coal seam mining are conducted in China and abundant experience is obtained. However, the researches involved strata pressure behavior of working faces with large inclined angle and hard roof are relatively less. In the study of strata pressure of coal stope, hard roof control is a significant part. Thus, it is of great theoretic importance and has engineering application value to study this project.Based on the 3(13)43 fully-mechanized face of hard roof of Daichiba mine with larege inclined angle and medium-thickness seam, theoretical analysis, numerical simulation and field measured data are applied in the paper to analyze the characteristics of fully-mechanized face of hard roof with large inclined angle and medium-thickness seam, including stope strata pressure distribution rule, surrounding rock stress state, roof caving law and relationship between support and surrounding rock. The main research findings are as follows:â‘ Combined theoretical analysis with numerical simulation and field measurement, the strata pressure law of fully-mechanized face of hard roof with large inclined angle and medium-thickness seam is systematically studied to confirm the first and the periodic caving interval of immediate roof and basic roof.â‘¡The strata pressure of occurrence of 13 coal seam in Daichiba Mine is analyzed in this paper. Combined with the mine pressure observation of hydraulic support, the conditions of large inclined angle, medium-thickness seam as well as hard roof are considered to obtain the parameters of support strength and weighted average support strength of 3(13)43 fully-mechanized face.â‘¢The support pressure of fully-mechanized hydraulic support is observed and analyzed to obtain the roof caving law. Moreover, the labor aptitude and operating feature of support are evaluated to provide basis for forecasting mine pressure, improving the safe surrounding of working face and enhancing support quality.â‘£Under the condition of large inclined angle and hard roof, presplitting blasting forcing caving technology is adopted to artificially shorten the first weighting interval of roof. And numerical simulation, theoretical analysis and field experiment are combined to validate the rationality of caving technology.