During high-intensity,fully mechanized mining of extra-thick coal seam,the top coal would cave to a certain 3D form.Based on the data collected during drilling,a 3D model of top coal caving surface space was establish...During high-intensity,fully mechanized mining of extra-thick coal seam,the top coal would cave to a certain 3D form.Based on the data collected during drilling,a 3D model of top coal caving surface space was established to determine the relationship between the location of the stope roof and the caving surface,enabling the mathematical computation of the top caving angle(φ).The drilling method was employed to measure the top caving angle on two extra-thick fully mechanized coal caving faces under the conditions of three geological structures,namely,no geological structure,igneous rock structure,and fault structure.The results show that the value of top caving angle could be accurately estimated on-site with the 9-parameter 3D top coal caving surface model built with the drilling method.This method is a novel on-site measurement that can be easily applied.Our findings reveal that the characteristics of the coal-rock in the two mining faces are different;yet their caving angles follow the ruleφ_(igneous rock structure)<φ_(no geological structure)<φ_(fault structure).Finally,through the data fitting with two indexes(the top coal uniaxial compressive strength and the top caving angle),it is found that the relationship between the two indexes satisfies an exponential decay function.展开更多
Based on the research method of combining simulation analysis with field testing by distinct element process UDEC, we have analyzed the roof deformation and failure laws and roadway support technology of gob-side entr...Based on the research method of combining simulation analysis with field testing by distinct element process UDEC, we have analyzed the roof deformation and failure laws and roadway support technology of gob-side entry retaining in a thin seam with a large inclined angle. The results show that during exploitation in seams with large inclined angle, rotational subsidence of the main roof under the gob area is small and can maintain balance, so there is no need to provide artificial permanent support resistance for the main roof near the upper side to control rotational subsidence. Obstructed by the dense scrap rail,waste rock from the immediate roof caving slides from the upper gob area to the lower area and fills it,which strikes a balance between the immediate roof under the goaf after it fractures into large pieces and filling waste rocks.展开更多
基金This work was supported by the Science and Technology Innovation Project of Higher Education in Shanxi Province(No.2019L0754)Central Guiding Local Science and Technology Development Fund project(No.YDZJSX2021B021)the Datong Science and Technology Plan Project(No.2019122).
文摘During high-intensity,fully mechanized mining of extra-thick coal seam,the top coal would cave to a certain 3D form.Based on the data collected during drilling,a 3D model of top coal caving surface space was established to determine the relationship between the location of the stope roof and the caving surface,enabling the mathematical computation of the top caving angle(φ).The drilling method was employed to measure the top caving angle on two extra-thick fully mechanized coal caving faces under the conditions of three geological structures,namely,no geological structure,igneous rock structure,and fault structure.The results show that the value of top caving angle could be accurately estimated on-site with the 9-parameter 3D top coal caving surface model built with the drilling method.This method is a novel on-site measurement that can be easily applied.Our findings reveal that the characteristics of the coal-rock in the two mining faces are different;yet their caving angles follow the ruleφ_(igneous rock structure)<φ_(no geological structure)<φ_(fault structure).Finally,through the data fitting with two indexes(the top coal uniaxial compressive strength and the top caving angle),it is found that the relationship between the two indexes satisfies an exponential decay function.
基金Financial support for this work was provided by the National Natural Science Foundation of China(No.51104176)
文摘Based on the research method of combining simulation analysis with field testing by distinct element process UDEC, we have analyzed the roof deformation and failure laws and roadway support technology of gob-side entry retaining in a thin seam with a large inclined angle. The results show that during exploitation in seams with large inclined angle, rotational subsidence of the main roof under the gob area is small and can maintain balance, so there is no need to provide artificial permanent support resistance for the main roof near the upper side to control rotational subsidence. Obstructed by the dense scrap rail,waste rock from the immediate roof caving slides from the upper gob area to the lower area and fills it,which strikes a balance between the immediate roof under the goaf after it fractures into large pieces and filling waste rocks.
