During shaft constructing, a borehole water inflow of 30 m3/h was encountered in Liu Yuanzi Coal Mine in the southwestern Ordos Basin, whose aquifer is mainly cretaceous. On the basis of regional hydrogeological condi...During shaft constructing, a borehole water inflow of 30 m3/h was encountered in Liu Yuanzi Coal Mine in the southwestern Ordos Basin, whose aquifer is mainly cretaceous. On the basis of regional hydrogeological conditions, a mercury intrusion method and scanning electron microscope were used in this study. We conclude that the loose, porous and easily collapsible clay particles of the cretaceous aquifer rock mass were the major geological cause for water hazards during the construction of the shaft. We propose an approach of chemical grouting from the working surface and in the end succeeded in blocking the water.展开更多
By analysing the hydrogeological conditions of this region and the coal mines hereof, together with the water hazards troubled Shennan mine area in recent years, this paper summarized six types of mine water hazards. ...By analysing the hydrogeological conditions of this region and the coal mines hereof, together with the water hazards troubled Shennan mine area in recent years, this paper summarized six types of mine water hazards. As per the basic characteristics, geological distribution, threat degree and difficulty of prevention of various water hazards, along with the practice of water prevention in the mining area, this article proposed effective technical measures for the prevention and control of different water hazards and laid a solid foundation for the safe production in the mining area.展开更多
Based on the transmitting theory of "smoke ring effect", the transient electromagnetism technique was used in coal mines to detect abnormal areas of aquiferous structures in both roofs and floors of coal sea...Based on the transmitting theory of "smoke ring effect", the transient electromagnetism technique was used in coal mines to detect abnormal areas of aquiferous structures in both roofs and floors of coal seams and in front of excavated roadways. Survey devices, working methods and techniques as well as data processing and interpretation are discussed systematically. In addition, the direction of mini-wireframe emission electromagnetic wave of the full space transient electromagnetism technique was verified by an underground borehole for water detection and drainage. The result indicates that this technique can detect both horizontal and vertical development rules of abnormal water bodies to a certain depth below the floor of coal seams and can also detect the abnormal, low resistance water bodies within a certain distance of roofs. Furthermore, it can detect such abnormal bodies in ahead of the excavated roadway front. Limited by the underground environment, the full space transient electromagnetism technique can detect to a depth of only 120 m or so.展开更多
Existing water hazard detection methods usually fail when the features of water surfaces are greatly changed by the surroundings, e.g., by a change in illumination. This paper proposes a novel algorithm to robustly de...Existing water hazard detection methods usually fail when the features of water surfaces are greatly changed by the surroundings, e.g., by a change in illumination. This paper proposes a novel algorithm to robustly detect different kinds of water hazards for autonomous navigation. Our algorithm combines traditional machine learning and image segmentation and uses only digital cameras, which are usually affordable, as the visual sensors. Active learning is used for automatically dealing with problems caused by the selection, labeling and classification of large numbers of training sets. Mean-shift based image segmentation is used to refine the final classification. Our experimental results show that our new algorithm can accurately detect not only ‘common’ water hazards, which usually have the features of both high brightness and low texture, but also ‘special’ water hazards that may have lots of ripples or low brightness.展开更多
Although about two-thirds of Nepalese families depend on agriculture as their major source of income, the agriculture is mostly rain-fed and it has been adversely affected by water hazards and the subsequent degradati...Although about two-thirds of Nepalese families depend on agriculture as their major source of income, the agriculture is mostly rain-fed and it has been adversely affected by water hazards and the subsequent degradation of resources. Based on case studies from three different geographical regions in Nepal, this research examines how environmental factors cause decreasing crop production and push people to abandon agriculture and accept emigration for employment. The research findings suggest a chain of push factors starting from drought or erratic rainfall causing water hazards, which impacts on depletion of crops and livestock, losses in income and employment and increased human mobility and emigration. The paper argues that the Government of Nepal and development partners can be more effective in enabling agrarian families to cope with the water hazards and shocks by formulating pro-poor mitigation and adaptation policies and strategies,focusing both on ‘rapid-onset' and ‘slow-onset' water hazards.展开更多
基金Financial support from the National Natural Science Foundation of China (No.40772191)
文摘During shaft constructing, a borehole water inflow of 30 m3/h was encountered in Liu Yuanzi Coal Mine in the southwestern Ordos Basin, whose aquifer is mainly cretaceous. On the basis of regional hydrogeological conditions, a mercury intrusion method and scanning electron microscope were used in this study. We conclude that the loose, porous and easily collapsible clay particles of the cretaceous aquifer rock mass were the major geological cause for water hazards during the construction of the shaft. We propose an approach of chemical grouting from the working surface and in the end succeeded in blocking the water.
文摘By analysing the hydrogeological conditions of this region and the coal mines hereof, together with the water hazards troubled Shennan mine area in recent years, this paper summarized six types of mine water hazards. As per the basic characteristics, geological distribution, threat degree and difficulty of prevention of various water hazards, along with the practice of water prevention in the mining area, this article proposed effective technical measures for the prevention and control of different water hazards and laid a solid foundation for the safe production in the mining area.
文摘Based on the transmitting theory of "smoke ring effect", the transient electromagnetism technique was used in coal mines to detect abnormal areas of aquiferous structures in both roofs and floors of coal seams and in front of excavated roadways. Survey devices, working methods and techniques as well as data processing and interpretation are discussed systematically. In addition, the direction of mini-wireframe emission electromagnetic wave of the full space transient electromagnetism technique was verified by an underground borehole for water detection and drainage. The result indicates that this technique can detect both horizontal and vertical development rules of abnormal water bodies to a certain depth below the floor of coal seams and can also detect the abnormal, low resistance water bodies within a certain distance of roofs. Furthermore, it can detect such abnormal bodies in ahead of the excavated roadway front. Limited by the underground environment, the full space transient electromagnetism technique can detect to a depth of only 120 m or so.
基金Project supported by the National Natural Science Foundation of China (Nos. 60505017 and 60534070)the Natural Science Foundation of Zhejiang Province, China (No. 2005C14008)
文摘Existing water hazard detection methods usually fail when the features of water surfaces are greatly changed by the surroundings, e.g., by a change in illumination. This paper proposes a novel algorithm to robustly detect different kinds of water hazards for autonomous navigation. Our algorithm combines traditional machine learning and image segmentation and uses only digital cameras, which are usually affordable, as the visual sensors. Active learning is used for automatically dealing with problems caused by the selection, labeling and classification of large numbers of training sets. Mean-shift based image segmentation is used to refine the final classification. Our experimental results show that our new algorithm can accurately detect not only ‘common’ water hazards, which usually have the features of both high brightness and low texture, but also ‘special’ water hazards that may have lots of ripples or low brightness.
文摘Although about two-thirds of Nepalese families depend on agriculture as their major source of income, the agriculture is mostly rain-fed and it has been adversely affected by water hazards and the subsequent degradation of resources. Based on case studies from three different geographical regions in Nepal, this research examines how environmental factors cause decreasing crop production and push people to abandon agriculture and accept emigration for employment. The research findings suggest a chain of push factors starting from drought or erratic rainfall causing water hazards, which impacts on depletion of crops and livestock, losses in income and employment and increased human mobility and emigration. The paper argues that the Government of Nepal and development partners can be more effective in enabling agrarian families to cope with the water hazards and shocks by formulating pro-poor mitigation and adaptation policies and strategies,focusing both on ‘rapid-onset' and ‘slow-onset' water hazards.
