This study is the result of long-term efforts of the authors’team to assess ground response of gob-side entry by roof cutting(GSERC)with hard main roof,aiming at scientific control for GSERC deformation.A comprehensi...This study is the result of long-term efforts of the authors’team to assess ground response of gob-side entry by roof cutting(GSERC)with hard main roof,aiming at scientific control for GSERC deformation.A comprehensive field measurement program was conducted to determine entry deformation,roof fracture zone,and anchor bolt(cable)loading.The results indicate that GSERC deformation presents asymmetric characteristics.The maximum convergence near roof cutting side is 458 mm during the primary use process and 1120 mm during the secondary reuse process.The entry deformation is closely associated with the primary development stage,primary use stage,and secondary reuse stage.The key block movement of roof cutting structure,a complex stress environment,and a mismatch in the supporting design scheme are the failure mechanism of GSERC.A controlling ideology for mining states,including regional and stage divisions,was proposed.Both dynamic and permanent support schemes have been implemented in the field.Engineering practice results indicate that the new support scheme can efficiently ensure long-term entry safety and could be a reliable approach for other engineering practices.展开更多
By field observation and simulating test in shallow seam longwall mining, the asymmetry breaking of main roof is discovered during the first weighting. Based on simulating model test and theoretical analysis, the mech...By field observation and simulating test in shallow seam longwall mining, the asymmetry breaking of main roof is discovered during the first weighting. Based on simulating model test and theoretical analysis, the mechanism of main roof first breaking is revealed, and the asymmetry breaking parameter is determined at all.展开更多
To clarify and control the collapse and weighting of main roof in longwall mining is one of the important research problems in ground control. Based on the results of physical model experiment and field measurement, t...To clarify and control the collapse and weighting of main roof in longwall mining is one of the important research problems in ground control. Based on the results of physical model experiment and field measurement, the behaviour of main roof above trapezoidal goaf or with fault is studied in this paper. The fracture and weighting of main roof above trapezoidal goaf are different from those above rectangular goaf. It depends on the mechanical relation between main roof blocks whether the plate blocks of main roof on both sides of fault simultaneously break and collapse.展开更多
A series of physical modelings in which a main roof is considered as a Kirchhoff plate supported or clammed by Winkler elastic foundation were performed to simulate the fracturing process of the main roof in longwall ...A series of physical modelings in which a main roof is considered as a Kirchhoff plate supported or clammed by Winkler elastic foundation were performed to simulate the fracturing process of the main roof in longwall mining. Based on these modelings spatial structures of the main roof after its fracture are described, blocks of the fractured main roof are classified and their behaviors are analyzed in this paper. Additionally, two stability indexes of the structures are defined, and the factors affecting stability of the structures with different boundaries and geometric conditions are discussed.展开更多
A water-resistant key strata model of a goaf floor prior to main roof weighting was developed to explore the relationship between water inrush from the floor and main roof weighting. The stress distribution,broken cha...A water-resistant key strata model of a goaf floor prior to main roof weighting was developed to explore the relationship between water inrush from the floor and main roof weighting. The stress distribution,broken characteristics, and the risk area for water inrush of the water-resistant key strata were analysed using elastic thin plate theory. The formula of the maximum water pressure tolerated by the waterresistant key strata was deduced. The effects of the caved load of the goaf, the goaf size prior to main roof weighting, the advancing distance of the workface or weighting step, and the thickness of the waterresistant key strata on the breaking and instability of the water-resistant key strata were analysed.The results indicate that the water inrush from the floor can be predicted and prevented by controlling the initial or periodic weighting step with measures such as artificial forced caving, thus achieving safe mining conditions above confined aquifers. The findings provide an important theoretical basis for determining water inrush from the floor when mining above confined aquifers.展开更多
针对复采工作面过平行空巷支架支护阻力计算的问题,通过现场调研和理论分析,建立了过空巷采场基本顶破断的力学模型,提出了影响复采采场基本顶超前断裂的3个因素:复采工作面与空巷间煤柱宽度、复采工作面与周期断裂线距离、空巷宽度。...针对复采工作面过平行空巷支架支护阻力计算的问题,通过现场调研和理论分析,建立了过空巷采场基本顶破断的力学模型,提出了影响复采采场基本顶超前断裂的3个因素:复采工作面与空巷间煤柱宽度、复采工作面与周期断裂线距离、空巷宽度。通过对影响因素的力学分析,得到了基本顶超前断裂的力学作用机理:复采工作面与空巷间煤柱随回采失稳,导致顶板失去煤柱支撑,基本顶梁结构的悬臂长度增加,当悬臂长度达到周期来压步距时,悬臂梁在固支端断裂。基于Bieniawski公式,推导得到了复采工作面与空巷间煤柱失稳的临界宽度W*和复采工作面基本顶必然产生超前断裂空巷临界宽度A0。根据过空巷采场基本顶破断力学模型对基本顶来压力学模型中断裂岩块尺寸进行了针对性调整,运用调整断裂岩块尺寸后的基本顶来压力学模型计算得到了适用于复采工作面的过空巷期间支架最小支护强度为10 910.77 k N/架。圣华煤业复采工作面过空巷期间的矿压观测结果表明:工作面过空巷期间,最大工作阻力为9 656 k N/架,支架支护强度计算合理。展开更多
基金Project(WPUKFJJ2019-19)supported by the Open Fund of State Key Laboratory of Water Resource Protection and Utilization in Coal Mining,ChinaProject(51974317)supported by the National Natural Science Foundation of China。
文摘This study is the result of long-term efforts of the authors’team to assess ground response of gob-side entry by roof cutting(GSERC)with hard main roof,aiming at scientific control for GSERC deformation.A comprehensive field measurement program was conducted to determine entry deformation,roof fracture zone,and anchor bolt(cable)loading.The results indicate that GSERC deformation presents asymmetric characteristics.The maximum convergence near roof cutting side is 458 mm during the primary use process and 1120 mm during the secondary reuse process.The entry deformation is closely associated with the primary development stage,primary use stage,and secondary reuse stage.The key block movement of roof cutting structure,a complex stress environment,and a mismatch in the supporting design scheme are the failure mechanism of GSERC.A controlling ideology for mining states,including regional and stage divisions,was proposed.Both dynamic and permanent support schemes have been implemented in the field.Engineering practice results indicate that the new support scheme can efficiently ensure long-term entry safety and could be a reliable approach for other engineering practices.
文摘By field observation and simulating test in shallow seam longwall mining, the asymmetry breaking of main roof is discovered during the first weighting. Based on simulating model test and theoretical analysis, the mechanism of main roof first breaking is revealed, and the asymmetry breaking parameter is determined at all.
文摘To clarify and control the collapse and weighting of main roof in longwall mining is one of the important research problems in ground control. Based on the results of physical model experiment and field measurement, the behaviour of main roof above trapezoidal goaf or with fault is studied in this paper. The fracture and weighting of main roof above trapezoidal goaf are different from those above rectangular goaf. It depends on the mechanical relation between main roof blocks whether the plate blocks of main roof on both sides of fault simultaneously break and collapse.
文摘A series of physical modelings in which a main roof is considered as a Kirchhoff plate supported or clammed by Winkler elastic foundation were performed to simulate the fracturing process of the main roof in longwall mining. Based on these modelings spatial structures of the main roof after its fracture are described, blocks of the fractured main roof are classified and their behaviors are analyzed in this paper. Additionally, two stability indexes of the structures are defined, and the factors affecting stability of the structures with different boundaries and geometric conditions are discussed.
基金supported by the National Natural Science Foundation of China (Nos. 51404013 and 51674008)the Open Projects of State Key Laboratory of Coal Resources and Safe Mining at the China University of Mining and Technology (No. 13KF01)the Natural Science Foundation of Anhui Province (Nos. 1508085ME77 and 1508085QE89)
文摘A water-resistant key strata model of a goaf floor prior to main roof weighting was developed to explore the relationship between water inrush from the floor and main roof weighting. The stress distribution,broken characteristics, and the risk area for water inrush of the water-resistant key strata were analysed using elastic thin plate theory. The formula of the maximum water pressure tolerated by the waterresistant key strata was deduced. The effects of the caved load of the goaf, the goaf size prior to main roof weighting, the advancing distance of the workface or weighting step, and the thickness of the waterresistant key strata on the breaking and instability of the water-resistant key strata were analysed.The results indicate that the water inrush from the floor can be predicted and prevented by controlling the initial or periodic weighting step with measures such as artificial forced caving, thus achieving safe mining conditions above confined aquifers. The findings provide an important theoretical basis for determining water inrush from the floor when mining above confined aquifers.
文摘针对复采工作面过平行空巷支架支护阻力计算的问题,通过现场调研和理论分析,建立了过空巷采场基本顶破断的力学模型,提出了影响复采采场基本顶超前断裂的3个因素:复采工作面与空巷间煤柱宽度、复采工作面与周期断裂线距离、空巷宽度。通过对影响因素的力学分析,得到了基本顶超前断裂的力学作用机理:复采工作面与空巷间煤柱随回采失稳,导致顶板失去煤柱支撑,基本顶梁结构的悬臂长度增加,当悬臂长度达到周期来压步距时,悬臂梁在固支端断裂。基于Bieniawski公式,推导得到了复采工作面与空巷间煤柱失稳的临界宽度W*和复采工作面基本顶必然产生超前断裂空巷临界宽度A0。根据过空巷采场基本顶破断力学模型对基本顶来压力学模型中断裂岩块尺寸进行了针对性调整,运用调整断裂岩块尺寸后的基本顶来压力学模型计算得到了适用于复采工作面的过空巷期间支架最小支护强度为10 910.77 k N/架。圣华煤业复采工作面过空巷期间的矿压观测结果表明:工作面过空巷期间,最大工作阻力为9 656 k N/架,支架支护强度计算合理。
