Huainan mining area is located in the southern margin of the North China Plate, which is an important coal-producing base in the eastern part of China, its deep coal seam mining is threatened by karst water inrush dis...Huainan mining area is located in the southern margin of the North China Plate, which is an important coal-producing base in the eastern part of China, its deep coal seam mining is threatened by karst water inrush disasters in the bottom plate, analyzing hydrogeochemical characteristics and exploring its causes are an important prerequisite for preventing karst water hazards in the coal floor. This paper takes the karst water of the Taiyuan Formation in the lower part of the A-group coal seam of the Xieqiao-Zhangji-Gubei three mines in the Panxie mining area as the research object, and multivariate statistics, hydrochemical analysis were combined with hydrogeochemical simulation. The hydrogeochemical Component characteristics and cause of formation of the karst water-bearing system covered by huge thick unconsolidated layer are discussed. The results show that the cations are dominated by Na+ + K+, and the anions are mainly Cl−and HCO3−in the karst water in Taiyuan Formation in the study area, mainly affected by the dissolution of salt rock and the oxidation of pyrite, there are cations exchange and adsorption and desulfurization.展开更多
For a study of the movement and deformation of coal-rock mass and low protected seams below a stope,as well as for fracture developments and rules of evolution of permeability,we designed a plane strain model test sta...For a study of the movement and deformation of coal-rock mass and low protected seams below a stope,as well as for fracture developments and rules of evolution of permeability,we designed a plane strain model test stand to carry out model tests of similar materials in order to improve the effect of gas drainage from low protected seams and to measure the movement and deformation of coal-rock mass using a method of non-contact close-range photogrammetry.Our results show that 1) using paraffin melting to take the place of coal seam mining can satisfy the mining conditions of a protective seam;2) coal-rock mass under goafs has an upward movement after the protective seam has been mined,causing floor heaving;3) low protected seams become swollen and deformed,providing a good pressure-relief effect and causing the coal-rock mass under both sides of coal pillars to become deformed by compression and 4) the evolution of permeability of low protected seams follows the way of initial values→a slight decrease→a great increase→stability→final decrease.Simultaneously,the coefficient of air permeability increased at a decreasing rate with an increase in interlayer spacing.展开更多
In order to solve effectively the problems of deep mining with safety and high efficiency,the multiple factors influencing the stability of deep rock roadway and technical problems are analyzed in the light of the sev...In order to solve effectively the problems of deep mining with safety and high efficiency,the multiple factors influencing the stability of deep rock roadway and technical problems are analyzed in the light of the severe situation of effective mining for deep coal resource,and the stability control methods for deep rock roadway are provided,which are based on the idea of combined support with separated steps and integral control of surrounding rock of deep rock roadway. The suggested methods were applied to a deep rock roadway with-648 m depth in Gubei coal mine of Huainan area. The field test was carried out and the in-situ monitoring was implemented,and the support scheme was optimized and adjusted to improve the stability of the surrounding rock of the roadway based on the feedback analysis. The results showed that the stability can be improved greatly by the provided control methods for deep roadway. The present methods for stability control of deep rock roadway can be used to other deep rock roadways with the similar conditions.展开更多
In order to investigate the behaviors and stability of rock strata surrounding an entry with bolt supporting in large dip coal seams (LDCSs) dipping from 25° to 45°, a self-developed rotatable experimental f...In order to investigate the behaviors and stability of rock strata surrounding an entry with bolt supporting in large dip coal seams (LDCSs) dipping from 25° to 45°, a self-developed rotatable experimental frame for similar material simulation test was used to build the model with the dip of 30°, based on analyses of geological and technological conditions in Huainan mine area, Anhui, China. The strata behaviors, such as extracting- and mining-induced stresses development, deformation and failure modes, were synthetically integrated during working face advancing. Results show that the development characteristics of mining-induced stress and deformation are asymmetrical in the roadway. The strata behaviors are totally different in different sections of the roadway. Because of asymmetrically geometrical structure influenced by increasing dip, strata dislocating, rock falling and breaking occur in roof. Then, squeezing, collapsing and caving of coal happen in upper- and lower-rib due to shearing action caused by asymmetrical roof bending and dislocating. Owing to the absence of supporting, floor heaving is very violent and usually the zone of floor heaving develops from the lower-rib to upper-rib. Engineering practices show that, due to the asymmetrical characteristics of rock pressure and roadway configuration, it is more difficult to implement bolt supporting system to control rock stability of roadways in LDCSs. The upper-rib and roof of entries are the key sections. Consequently, it is reliable to use asymmetrical bolt-mesh-cable supporting system to control rock stability of roadways based on the asymmetrical characteristics of roadway configuration and strata behaviors.展开更多
Based on the pipe transportation of paste-like backfilling system of a certain deep coal mine,its dynamics process was simulated and analyzed.A two-dimensional dynamic model of extraordinary deep and lone pipe was bui...Based on the pipe transportation of paste-like backfilling system of a certain deep coal mine,its dynamics process was simulated and analyzed.A two-dimensional dynamic model of extraordinary deep and lone pipe was built by GAMBIT,on the basis of which the simulation was done by implicit solver of FLUENT 2ddp.The results show that hydraulic loss of pipe transportation is less than the pressure produced by gravity,which means the backfilling material can flow by itself.When the inlet velocity is 3.2 m/s,the maximum velocity of 4.10 m/s is at the elbow and the maximum velocity in the horizontal pipe is 3.91 m/s,which can both meet the stability requirement.The results of the simulation are proved to be reliable by the residual monitor plotting of related parameter,so it can be concluded that the system of pipe transportation is safe.展开更多
Exogenous humus can change the content and migration activity of cadmium(Cd)in soil.Humic acid(HA)is an important soluble humus component in soil.In order to explore the relationship between cadmium pollution mechanis...Exogenous humus can change the content and migration activity of cadmium(Cd)in soil.Humic acid(HA)is an important soluble humus component in soil.In order to explore the relationship between cadmium pollution mechanism and ecological environment of humic acid in reclaimed soil,the characteristics of humic acid adsorbing cadmium in alkaline conditions were studied.This study employed reclaimed soil from the Huainan mining area,China.The adsorption and desorption characteristics as well as influence mechanisms on the heavy metal cadmium(Cd)were explored under the influence of HA.The results show that:(1)When Cd concentration was low(0.2–10 mg/L),HA had little effect on Cd adsorption and desorption in reclaimed soil.When the Cd concentration was high(15–80 mg/L),HA had a great influence on the adsorption and desorption of Cd in reclaimed soil.The addition of HA can inhibit the adsorption of Cd by reclaimed soil and effectively improve the desorption capacity of Cd by reclaimed soil.(2)The kinetic curves of Cd adsorption and desorption of reclaimed soil with added HA show that both processes(adsorption and desorption)include two stages:rapid reaction and slow reaction.The adsorption of Cd by reclaimed soil under the influence of HA was 18.18%lower than that of normal reclaimed soil,and the increase of Cd desorption was 50.29%.(3)The factors affecting the adsorption and desorption of Cd in the soil were analyzed with gray theory,and their importance can be ordered as follows:Cd concentration>HA concentration>pH>temperature.Considering the influence of HA,a multi-factor coupling function model of adsorption and desorption of Cd in soil is established.This model provides theoretical guidance for the scientific prediction and evaluation of Cd environmental pollution risks in soil and will be useful for developing a new solution for engineering remediation of high concentration Cd contaminated soil.展开更多
A combustion tube experiment platform was designed and used to study the inerting conditions and capacity of entrained atomized water on premixed methane–air flame. The structure of a laminar flame of premixed methan...A combustion tube experiment platform was designed and used to study the inerting conditions and capacity of entrained atomized water on premixed methane–air flame. The structure of a laminar flame of premixed methane–air gas and the process of interaction between atomized water and flame was recorded, and the rules of combustion velocity, stability and strength rate of laminar flame were experimentally studied. The inerting process and mechanism was analyzed, and the characteristics of inerting premixed methane–air gas within explosion limits by atomized water were acquired. The research results show that: for the premixed methane–air gas with a concentration of 7%, the minimum inerting atomized water flux is 20.8 m L/(m2min); for the premixed methane–air gas with a concentration of 9%, the minimum inerting atomized water flux is 32.9 m L/(m2min); for the premixed methane–air gas with a concentration of 11%, the minimum inerting atomized water flux is 44.6 m L/(m2min). The research results are significant for extinguishing methane flame and inhibiting of methane explosion using atomized water.展开更多
文摘Huainan mining area is located in the southern margin of the North China Plate, which is an important coal-producing base in the eastern part of China, its deep coal seam mining is threatened by karst water inrush disasters in the bottom plate, analyzing hydrogeochemical characteristics and exploring its causes are an important prerequisite for preventing karst water hazards in the coal floor. This paper takes the karst water of the Taiyuan Formation in the lower part of the A-group coal seam of the Xieqiao-Zhangji-Gubei three mines in the Panxie mining area as the research object, and multivariate statistics, hydrochemical analysis were combined with hydrogeochemical simulation. The hydrogeochemical Component characteristics and cause of formation of the karst water-bearing system covered by huge thick unconsolidated layer are discussed. The results show that the cations are dominated by Na+ + K+, and the anions are mainly Cl−and HCO3−in the karst water in Taiyuan Formation in the study area, mainly affected by the dissolution of salt rock and the oxidation of pyrite, there are cations exchange and adsorption and desulfurization.
基金the Major Programs of the National Basic Research Program of China (No.2005CB221503)the National Natural Science Foundation of China (Nos. 70533050 and 50674089) for their support of this project
文摘For a study of the movement and deformation of coal-rock mass and low protected seams below a stope,as well as for fracture developments and rules of evolution of permeability,we designed a plane strain model test stand to carry out model tests of similar materials in order to improve the effect of gas drainage from low protected seams and to measure the movement and deformation of coal-rock mass using a method of non-contact close-range photogrammetry.Our results show that 1) using paraffin melting to take the place of coal seam mining can satisfy the mining conditions of a protective seam;2) coal-rock mass under goafs has an upward movement after the protective seam has been mined,causing floor heaving;3) low protected seams become swollen and deformed,providing a good pressure-relief effect and causing the coal-rock mass under both sides of coal pillars to become deformed by compression and 4) the evolution of permeability of low protected seams follows the way of initial values→a slight decrease→a great increase→stability→final decrease.Simultaneously,the coefficient of air permeability increased at a decreasing rate with an increase in interlayer spacing.
文摘In order to solve effectively the problems of deep mining with safety and high efficiency,the multiple factors influencing the stability of deep rock roadway and technical problems are analyzed in the light of the severe situation of effective mining for deep coal resource,and the stability control methods for deep rock roadway are provided,which are based on the idea of combined support with separated steps and integral control of surrounding rock of deep rock roadway. The suggested methods were applied to a deep rock roadway with-648 m depth in Gubei coal mine of Huainan area. The field test was carried out and the in-situ monitoring was implemented,and the support scheme was optimized and adjusted to improve the stability of the surrounding rock of the roadway based on the feedback analysis. The results showed that the stability can be improved greatly by the provided control methods for deep roadway. The present methods for stability control of deep rock roadway can be used to other deep rock roadways with the similar conditions.
基金Supported by the National Basic Research Program of China (2010CB226806)the Visiting Scholar Foundation of Key Laboratory for Exploitation of Southwestern Resources and Environmental Disaster Control Engineeringthe Outstanding Innovation Group Program of Anhui University of Science and Technology
文摘In order to investigate the behaviors and stability of rock strata surrounding an entry with bolt supporting in large dip coal seams (LDCSs) dipping from 25° to 45°, a self-developed rotatable experimental frame for similar material simulation test was used to build the model with the dip of 30°, based on analyses of geological and technological conditions in Huainan mine area, Anhui, China. The strata behaviors, such as extracting- and mining-induced stresses development, deformation and failure modes, were synthetically integrated during working face advancing. Results show that the development characteristics of mining-induced stress and deformation are asymmetrical in the roadway. The strata behaviors are totally different in different sections of the roadway. Because of asymmetrically geometrical structure influenced by increasing dip, strata dislocating, rock falling and breaking occur in roof. Then, squeezing, collapsing and caving of coal happen in upper- and lower-rib due to shearing action caused by asymmetrical roof bending and dislocating. Owing to the absence of supporting, floor heaving is very violent and usually the zone of floor heaving develops from the lower-rib to upper-rib. Engineering practices show that, due to the asymmetrical characteristics of rock pressure and roadway configuration, it is more difficult to implement bolt supporting system to control rock stability of roadways in LDCSs. The upper-rib and roof of entries are the key sections. Consequently, it is reliable to use asymmetrical bolt-mesh-cable supporting system to control rock stability of roadways based on the asymmetrical characteristics of roadway configuration and strata behaviors.
基金Project(2008BAB32B03) supported by the National Science and Technology Pillar Program during the 11th Five-year Plan Period of China
文摘Based on the pipe transportation of paste-like backfilling system of a certain deep coal mine,its dynamics process was simulated and analyzed.A two-dimensional dynamic model of extraordinary deep and lone pipe was built by GAMBIT,on the basis of which the simulation was done by implicit solver of FLUENT 2ddp.The results show that hydraulic loss of pipe transportation is less than the pressure produced by gravity,which means the backfilling material can flow by itself.When the inlet velocity is 3.2 m/s,the maximum velocity of 4.10 m/s is at the elbow and the maximum velocity in the horizontal pipe is 3.91 m/s,which can both meet the stability requirement.The results of the simulation are proved to be reliable by the residual monitor plotting of related parameter,so it can be concluded that the system of pipe transportation is safe.
基金This research was supported by the National Natural Science Foundation of China(No.51904014)the Natural Science Research Project of University in Anhui Province(No.KJ2018A0072)the Postdoctoral Foundation of Anhui Province(No.2019B337).
文摘Exogenous humus can change the content and migration activity of cadmium(Cd)in soil.Humic acid(HA)is an important soluble humus component in soil.In order to explore the relationship between cadmium pollution mechanism and ecological environment of humic acid in reclaimed soil,the characteristics of humic acid adsorbing cadmium in alkaline conditions were studied.This study employed reclaimed soil from the Huainan mining area,China.The adsorption and desorption characteristics as well as influence mechanisms on the heavy metal cadmium(Cd)were explored under the influence of HA.The results show that:(1)When Cd concentration was low(0.2–10 mg/L),HA had little effect on Cd adsorption and desorption in reclaimed soil.When the Cd concentration was high(15–80 mg/L),HA had a great influence on the adsorption and desorption of Cd in reclaimed soil.The addition of HA can inhibit the adsorption of Cd by reclaimed soil and effectively improve the desorption capacity of Cd by reclaimed soil.(2)The kinetic curves of Cd adsorption and desorption of reclaimed soil with added HA show that both processes(adsorption and desorption)include two stages:rapid reaction and slow reaction.The adsorption of Cd by reclaimed soil under the influence of HA was 18.18%lower than that of normal reclaimed soil,and the increase of Cd desorption was 50.29%.(3)The factors affecting the adsorption and desorption of Cd in the soil were analyzed with gray theory,and their importance can be ordered as follows:Cd concentration>HA concentration>pH>temperature.Considering the influence of HA,a multi-factor coupling function model of adsorption and desorption of Cd in soil is established.This model provides theoretical guidance for the scientific prediction and evaluation of Cd environmental pollution risks in soil and will be useful for developing a new solution for engineering remediation of high concentration Cd contaminated soil.
基金supported by the National Natural Science Foundation of China(No.51304006)the Natural Science Foundation of Anhui Province(No.1408085QE87)the Training Fund for Youth Backbones of Anhui University of Science&Technology(No.20120012)
文摘A combustion tube experiment platform was designed and used to study the inerting conditions and capacity of entrained atomized water on premixed methane–air flame. The structure of a laminar flame of premixed methane–air gas and the process of interaction between atomized water and flame was recorded, and the rules of combustion velocity, stability and strength rate of laminar flame were experimentally studied. The inerting process and mechanism was analyzed, and the characteristics of inerting premixed methane–air gas within explosion limits by atomized water were acquired. The research results show that: for the premixed methane–air gas with a concentration of 7%, the minimum inerting atomized water flux is 20.8 m L/(m2min); for the premixed methane–air gas with a concentration of 9%, the minimum inerting atomized water flux is 32.9 m L/(m2min); for the premixed methane–air gas with a concentration of 11%, the minimum inerting atomized water flux is 44.6 m L/(m2min). The research results are significant for extinguishing methane flame and inhibiting of methane explosion using atomized water.