In order to control asymmetric floor heave in deep rock roadways and deformation around the surrounding rock mass after excavation, in this paper we discuss the failure mechanism and coupling control countermeasures u...In order to control asymmetric floor heave in deep rock roadways and deformation around the surrounding rock mass after excavation, in this paper we discuss the failure mechanism and coupling control countermeasures using the finite difference method （FLAC^3D） combined with comparative analysis and typical engineering application at Xingcun coal mine, It is indicated by the analysis that the simple symmetric support systems used in the past led to destruction of the deep rock roadway from the key zone and resulted in the deformation of asymmetric floor heave in the roadway. Suitable rein- forced support countermeasures are proposed to reduce the deformation of the floor heave and the potential risk during mining. The application shows that the present support technology can he used to better environmental conditions. The countermeasures of asymmetric coupling support can not only effectively reduce the discrepancy deformation at the key area of the surrounding rock mass, hut also effectively control floor heave, which helps realize the integration of support and maintain the stability of the deep rock roadways at Xingcun coal mine.展开更多
Based on in-mine instrumentation and theoretical analysis of the unsymmetrical large-deformation that occurred in the roadway after excavation,Differential Floor Heave(DFH)was found to be the main reason for roadway f...Based on in-mine instrumentation and theoretical analysis of the unsymmetrical large-deformation that occurred in the roadway after excavation,Differential Floor Heave(DFH)was found to be the main reason for roadway failure.It needs to be pointed out that the specific roadway was driven in inclined rock strata.In addition,the factors that contribute to the occurrence of DFH are discussed in detail.It is believed that DFH is triggered by the unsymmetrical stress distribution in the floor and the different rock types encountered near the two floor corners.Hence,DFH control should be focused on the left floor corner where shearing failure occurs initially and the left floor surface where tensile failure is more severe.The proposed DFH control strategies include unsymmetrical grouting for the whole roadway,re-design of the roof and ribs support,reinforcement of the weak zones,and release of the concentrated stress in the earlier stage.Meanwhile,it is recommended that in the later stage,both bolts and cable bolts with higher strength and the backfilling technique using the coal measure rocks and concrete should be employed in the reversed-arch floor.The field instrumentation results,after using the proposed control strategies,indicate that large deformation in a DFH roadway has been successfully controlled.展开更多
Deep coal seam mining floor strata water bursting is a complicate nonlinear system, whose factors are coupling and influencing themselves. It built the analytic structure model for deep coal seam mining floor strata w...Deep coal seam mining floor strata water bursting is a complicate nonlinear system, whose factors are coupling and influencing themselves. It built the analytic structure model for deep coal seam mining floor strata water bursting, the judgment matrix was found by the expert scoring method, the contribution weights of the influenced factors were given out by the equation analytic process. The thirteen controlling factors and five main controlling factors were put award by analyzing weights, so the result was basically conform to the field practice. The expert scoring method and analytic process can convert the objective fact to the subjective cognition, so it is a method that can turn the qualitative into the quantitative. This can be relative objectively and precisely to study the question of many factors and grey box.展开更多
林地在全球生态系统中扮演着至关重要的角色。但传统监督学习方法在林地提取上存在特征选择不精确与未能充分利用像元间的上下文关系等缺陷,导致林地提取精度不理想。针对上述问题,本文提出了一种基于改进PSPNet(Pyramid Scene Parsing ...林地在全球生态系统中扮演着至关重要的角色。但传统监督学习方法在林地提取上存在特征选择不精确与未能充分利用像元间的上下文关系等缺陷,导致林地提取精度不理想。针对上述问题,本文提出了一种基于改进PSPNet(Pyramid Scene Parsing Network)模型的高分辨率遥感影像林地提取方法。首先,利用高分二号遥感影像与全国第三次土地调查数据,制作高分辨率林地数据集。其次,通过在原始PSPNet模型的基础上加入SE(Squeeze and Excitation)注意力模块,改进PSPNet模型。实验结果表明,本文所改进的PSPNet模型的各项精度指标均优于其他方法,具有较高的提取精度。展开更多
Roadway instability has been a major concern in the fields of mining engineering. This paper aims to provide practical and efficient strategy to support the roadways under high in-situ stress. A case study on the stab...Roadway instability has been a major concern in the fields of mining engineering. This paper aims to provide practical and efficient strategy to support the roadways under high in-situ stress. A case study on the stability of deep roadways was carried out in an underground mine in Gansu province, China. Currently,the surrounding rock strata is extremely fractured, which results in a series of engineering disasters, such as side wall collapse and severe floor heave in the past decades. Aiming to solve these problems, an improved support method was proposed, which includes optimal bolt parameters and arrangement, floor beam layout by grooving, and full length grouting. Based on the modeling results by FLAC3D, the new support method is much better than the current one in terms of preventing the large deformation of surrounding rock and restricting the development of plastic zones. For implementation and verification, field experiments, along with deformation monitoring, were conducted in the 958 level roadway of Mining II areas. The results show that the improved support can significantly reduce surrounding rock deformation, avoid frequent repair, and maintain the long-term stability of the roadway. Compared to the original support, the new support method can greatly save investment of mines, and has good application value and popularization value.展开更多
基金support from the National Natural Science Foundation of China (Nos. 51134005, 51374214, 41172116, and U1261212)the New Century Excellent Talents Foundation in University (No. NCET-07-0800)the Special Fund of Basic Research and Operating of China University of Mining & Technology in Beijing (No. 2009QL03)
文摘In order to control asymmetric floor heave in deep rock roadways and deformation around the surrounding rock mass after excavation, in this paper we discuss the failure mechanism and coupling control countermeasures using the finite difference method （FLAC^3D） combined with comparative analysis and typical engineering application at Xingcun coal mine, It is indicated by the analysis that the simple symmetric support systems used in the past led to destruction of the deep rock roadway from the key zone and resulted in the deformation of asymmetric floor heave in the roadway. Suitable rein- forced support countermeasures are proposed to reduce the deformation of the floor heave and the potential risk during mining. The application shows that the present support technology can he used to better environmental conditions. The countermeasures of asymmetric coupling support can not only effectively reduce the discrepancy deformation at the key area of the surrounding rock mass, hut also effectively control floor heave, which helps realize the integration of support and maintain the stability of the deep rock roadways at Xingcun coal mine.
基金financially supported by the National Natural Science Foundation of China (Nos.51204166 and 51174195)the Graduate Student Research Innovation Project of Ordinary University in Jiangsu Province (2013) (No.CXLX13_952)
文摘Based on in-mine instrumentation and theoretical analysis of the unsymmetrical large-deformation that occurred in the roadway after excavation,Differential Floor Heave(DFH)was found to be the main reason for roadway failure.It needs to be pointed out that the specific roadway was driven in inclined rock strata.In addition,the factors that contribute to the occurrence of DFH are discussed in detail.It is believed that DFH is triggered by the unsymmetrical stress distribution in the floor and the different rock types encountered near the two floor corners.Hence,DFH control should be focused on the left floor corner where shearing failure occurs initially and the left floor surface where tensile failure is more severe.The proposed DFH control strategies include unsymmetrical grouting for the whole roadway,re-design of the roof and ribs support,reinforcement of the weak zones,and release of the concentrated stress in the earlier stage.Meanwhile,it is recommended that in the later stage,both bolts and cable bolts with higher strength and the backfilling technique using the coal measure rocks and concrete should be employed in the reversed-arch floor.The field instrumentation results,after using the proposed control strategies,indicate that large deformation in a DFH roadway has been successfully controlled.
文摘Deep coal seam mining floor strata water bursting is a complicate nonlinear system, whose factors are coupling and influencing themselves. It built the analytic structure model for deep coal seam mining floor strata water bursting, the judgment matrix was found by the expert scoring method, the contribution weights of the influenced factors were given out by the equation analytic process. The thirteen controlling factors and five main controlling factors were put award by analyzing weights, so the result was basically conform to the field practice. The expert scoring method and analytic process can convert the objective fact to the subjective cognition, so it is a method that can turn the qualitative into the quantitative. This can be relative objectively and precisely to study the question of many factors and grey box.
文摘林地在全球生态系统中扮演着至关重要的角色。但传统监督学习方法在林地提取上存在特征选择不精确与未能充分利用像元间的上下文关系等缺陷,导致林地提取精度不理想。针对上述问题,本文提出了一种基于改进PSPNet(Pyramid Scene Parsing Network)模型的高分辨率遥感影像林地提取方法。首先,利用高分二号遥感影像与全国第三次土地调查数据,制作高分辨率林地数据集。其次,通过在原始PSPNet模型的基础上加入SE(Squeeze and Excitation)注意力模块,改进PSPNet模型。实验结果表明,本文所改进的PSPNet模型的各项精度指标均优于其他方法,具有较高的提取精度。
基金Financial supports for this work, provided by the Major Program of the National Natural Science Foundation of China (Nos. 51174228 and 51474249)the Program for New Century Excellent Talents in University the Open Project of State Key Laboratory of Coal resources and Safe Mining, China University of Mining and Technology
文摘Roadway instability has been a major concern in the fields of mining engineering. This paper aims to provide practical and efficient strategy to support the roadways under high in-situ stress. A case study on the stability of deep roadways was carried out in an underground mine in Gansu province, China. Currently,the surrounding rock strata is extremely fractured, which results in a series of engineering disasters, such as side wall collapse and severe floor heave in the past decades. Aiming to solve these problems, an improved support method was proposed, which includes optimal bolt parameters and arrangement, floor beam layout by grooving, and full length grouting. Based on the modeling results by FLAC3D, the new support method is much better than the current one in terms of preventing the large deformation of surrounding rock and restricting the development of plastic zones. For implementation and verification, field experiments, along with deformation monitoring, were conducted in the 958 level roadway of Mining II areas. The results show that the improved support can significantly reduce surrounding rock deformation, avoid frequent repair, and maintain the long-term stability of the roadway. Compared to the original support, the new support method can greatly save investment of mines, and has good application value and popularization value.
