When mining the fully-mechanized longwall caving face along strike, the unstable equipment, the low top-coal recovery ratio and the difficulty in controlling surrounding rock may occur due to large dip angle. Consider...When mining the fully-mechanized longwall caving face along strike, the unstable equipment, the low top-coal recovery ratio and the difficulty in controlling surrounding rock may occur due to large dip angle. Considering the effects of strike angle on support stability, the ‘‘support-surrounding rock"mechanical models of support topple and support slip were established in this paper. On the basis, the influencing factors of support stability were analyzed and the technical measures of controlling support and surrounding rock stability were put forward. Then the loose particles simulation experiment was conducted to analyze the impacts of caving directions and methods on the top-coal recovery in large dip angle fully-mechanized caving face. Finally, the ‘‘upward sequence and double-openings doublerounds" caving technology was determined. The research results are of great scientific significance and practical values to improve large dip thick seam mining technology.展开更多
In order to investigate the behaviors and stability of rock strata surrounding an entry with bolt supporting in large dip coal seams (LDCSs) dipping from 25° to 45°, a self-developed rotatable experimental f...In order to investigate the behaviors and stability of rock strata surrounding an entry with bolt supporting in large dip coal seams (LDCSs) dipping from 25° to 45°, a self-developed rotatable experimental frame for similar material simulation test was used to build the model with the dip of 30°, based on analyses of geological and technological conditions in Huainan mine area, Anhui, China. The strata behaviors, such as extracting- and mining-induced stresses development, deformation and failure modes, were synthetically integrated during working face advancing. Results show that the development characteristics of mining-induced stress and deformation are asymmetrical in the roadway. The strata behaviors are totally different in different sections of the roadway. Because of asymmetrically geometrical structure influenced by increasing dip, strata dislocating, rock falling and breaking occur in roof. Then, squeezing, collapsing and caving of coal happen in upper- and lower-rib due to shearing action caused by asymmetrical roof bending and dislocating. Owing to the absence of supporting, floor heaving is very violent and usually the zone of floor heaving develops from the lower-rib to upper-rib. Engineering practices show that, due to the asymmetrical characteristics of rock pressure and roadway configuration, it is more difficult to implement bolt supporting system to control rock stability of roadways in LDCSs. The upper-rib and roof of entries are the key sections. Consequently, it is reliable to use asymmetrical bolt-mesh-cable supporting system to control rock stability of roadways based on the asymmetrical characteristics of roadway configuration and strata behaviors.展开更多
基金provided by the National Key Basic Research Program of China (973 Program) (No. 2015CB251600)the Qing Lan Projectthe Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)
文摘When mining the fully-mechanized longwall caving face along strike, the unstable equipment, the low top-coal recovery ratio and the difficulty in controlling surrounding rock may occur due to large dip angle. Considering the effects of strike angle on support stability, the ‘‘support-surrounding rock"mechanical models of support topple and support slip were established in this paper. On the basis, the influencing factors of support stability were analyzed and the technical measures of controlling support and surrounding rock stability were put forward. Then the loose particles simulation experiment was conducted to analyze the impacts of caving directions and methods on the top-coal recovery in large dip angle fully-mechanized caving face. Finally, the ‘‘upward sequence and double-openings doublerounds" caving technology was determined. The research results are of great scientific significance and practical values to improve large dip thick seam mining technology.
基金Supported by the National Basic Research Program of China (2010CB226806)the Visiting Scholar Foundation of Key Laboratory for Exploitation of Southwestern Resources and Environmental Disaster Control Engineeringthe Outstanding Innovation Group Program of Anhui University of Science and Technology
文摘In order to investigate the behaviors and stability of rock strata surrounding an entry with bolt supporting in large dip coal seams (LDCSs) dipping from 25° to 45°, a self-developed rotatable experimental frame for similar material simulation test was used to build the model with the dip of 30°, based on analyses of geological and technological conditions in Huainan mine area, Anhui, China. The strata behaviors, such as extracting- and mining-induced stresses development, deformation and failure modes, were synthetically integrated during working face advancing. Results show that the development characteristics of mining-induced stress and deformation are asymmetrical in the roadway. The strata behaviors are totally different in different sections of the roadway. Because of asymmetrically geometrical structure influenced by increasing dip, strata dislocating, rock falling and breaking occur in roof. Then, squeezing, collapsing and caving of coal happen in upper- and lower-rib due to shearing action caused by asymmetrical roof bending and dislocating. Owing to the absence of supporting, floor heaving is very violent and usually the zone of floor heaving develops from the lower-rib to upper-rib. Engineering practices show that, due to the asymmetrical characteristics of rock pressure and roadway configuration, it is more difficult to implement bolt supporting system to control rock stability of roadways in LDCSs. The upper-rib and roof of entries are the key sections. Consequently, it is reliable to use asymmetrical bolt-mesh-cable supporting system to control rock stability of roadways based on the asymmetrical characteristics of roadway configuration and strata behaviors.
