Caving of mine roofs from water inrush due to anomalous pressure is one of the major disasters and accidents that can occur in mines during production.Roof water inrush can trigger a wide range of roof collapse,causin...Caving of mine roofs from water inrush due to anomalous pressure is one of the major disasters and accidents that can occur in mines during production.Roof water inrush can trigger a wide range of roof collapse,causing major accidents from breaking roof supports while caving.These failures flood wells and do a great deal of damage to mines and endanger mine safety.Our objective is to analyze the anomalies of water inrush crushing the support at the #6301 working face in the Jisan Coal Mine of the Yanzhou Mining Group.Through information of water inrush to the roof,damage caused by tectonic movements,information on the damage caused by roof collapse and the theory about the distribution of pressure in mine abutments,we advice adjusting the length of the working face and the position of open-off cut relatively to the rich water area.In the case of anomalous roof pressure we should develop a state equation to estimate preventive measures with＂transferring rock beam＂theory.Simultaneously, we improve the capacity of drainage equipment and ensured adequate water retention at the storehouse. These are all major technologies to ensure the control and prevention against accidents caused by anomalous water inrush in roofs,thus ensuring safety in the production process of a coal mine.展开更多
Hydraulic fracturing is one of the efficient means for the abundant low-permeability CBM （coal-bed methane） reserves in China, however, due to the unique features of coal seams （i.e., low temperature, strong adsorp...Hydraulic fracturing is one of the efficient means for the abundant low-permeability CBM （coal-bed methane） reserves in China, however, due to the unique features of coal seams （i.e., low temperature, strong adsorption and abnormal development of natural fracture systems） as compared with the conventional reservoirs, the fractures propagate is difficult and the risk of damage to coal seam itself and the hydraulic fractures would be extremely high in the course of fracturing. As a result, losses would be suffered on the post-frac production of CBM wells.With the mean of numerical simulation, in this paper, the main factors have impact on the post-frac results as well as the extent to which the impact is brought were researched, and the technical solutions for the improvement of the fracturing performance was put forwards.展开更多
Water shows anomalies different from most of other materials.Different sceniaros have been proposed to explain water anomalies,among which the liquid-liquid phase transition(LLPT)is the most discussed one.It attribute...Water shows anomalies different from most of other materials.Different sceniaros have been proposed to explain water anomalies,among which the liquid-liquid phase transition(LLPT)is the most discussed one.It attributes water anomalies to the existence of a hypothesized liquid-liquid critical point(LLCP)buried deep in the supercooled region.We briefly review the recent experimental and theoretical progresses on the study of the LLPT in water.These studies include the discussion on the existence of the first order LLPT in supercooled water and the detection of liquid-liquid critical point.Simulational results of different water models for LLPT and the experimental evidence in confined water are also discussed.展开更多
基金sponsored by the National Natural Science Foundation of China(No.50874021 )the Program for New Century Excellent Talents in University(No.NCET-08-0833)the Program for Changjiang Scholars and Innovative Research Team in University(No.IRT0656) of the Ministry of Education of China.
文摘Caving of mine roofs from water inrush due to anomalous pressure is one of the major disasters and accidents that can occur in mines during production.Roof water inrush can trigger a wide range of roof collapse,causing major accidents from breaking roof supports while caving.These failures flood wells and do a great deal of damage to mines and endanger mine safety.Our objective is to analyze the anomalies of water inrush crushing the support at the #6301 working face in the Jisan Coal Mine of the Yanzhou Mining Group.Through information of water inrush to the roof,damage caused by tectonic movements,information on the damage caused by roof collapse and the theory about the distribution of pressure in mine abutments,we advice adjusting the length of the working face and the position of open-off cut relatively to the rich water area.In the case of anomalous roof pressure we should develop a state equation to estimate preventive measures with＂transferring rock beam＂theory.Simultaneously, we improve the capacity of drainage equipment and ensured adequate water retention at the storehouse. These are all major technologies to ensure the control and prevention against accidents caused by anomalous water inrush in roofs,thus ensuring safety in the production process of a coal mine.
文摘Hydraulic fracturing is one of the efficient means for the abundant low-permeability CBM （coal-bed methane） reserves in China, however, due to the unique features of coal seams （i.e., low temperature, strong adsorption and abnormal development of natural fracture systems） as compared with the conventional reservoirs, the fractures propagate is difficult and the risk of damage to coal seam itself and the hydraulic fractures would be extremely high in the course of fracturing. As a result, losses would be suffered on the post-frac production of CBM wells.With the mean of numerical simulation, in this paper, the main factors have impact on the post-frac results as well as the extent to which the impact is brought were researched, and the technical solutions for the improvement of the fracturing performance was put forwards.
基金supported by the National Natural Science Foundation of China(Grant Nos.11290162/A040106,10974238,11274012,91021007and 11174006)the National Basic Research Program of China(GrantNo.2012CB921404)
文摘Water shows anomalies different from most of other materials.Different sceniaros have been proposed to explain water anomalies,among which the liquid-liquid phase transition(LLPT)is the most discussed one.It attributes water anomalies to the existence of a hypothesized liquid-liquid critical point(LLCP)buried deep in the supercooled region.We briefly review the recent experimental and theoretical progresses on the study of the LLPT in water.These studies include the discussion on the existence of the first order LLPT in supercooled water and the detection of liquid-liquid critical point.Simulational results of different water models for LLPT and the experimental evidence in confined water are also discussed.
