Based on the characteristics of the deep circular tunnel, the surrounding rock was divided into three regions： the cracked region, the plastic region and the viscoelastic region. The process of rock stress deformatio...Based on the characteristics of the deep circular tunnel, the surrounding rock was divided into three regions： the cracked region, the plastic region and the viscoelastic region. The process of rock stress deformation and change was divided into three stages after the roadway excavation. By using the elastic-plastic mechanics theory, the analytical solutions of the surrounding stress and displacement at different stages and the radii of cracked and plastic regions were formulated. We additionally explained the surrounding rock stress and displacement which appeared in practical project. Simultaneously, based on the problem which emerged from a mine in Xuzhou during the excavating process of rock roadway＇s transport, we got the theoretical solutions for the stress and displacement in the process of rock roadway＇s excavation and considered that the broken area of rock roadway was largely loosing circle. The results indicate that according to the rheological characteristics of surrounding rock, in the primeval excavation of rock roadway, we should increase the length of anchor bolt and cooperate it with anchor nets cable-U steel supporting frame. In addition, when the deformation rate of the surrounding rock is descending after the 15 days＇ excavation, we should use the ＂three anchor＂ supporting method （anchor bolt spray, anchor note and anchor rove） and set aside about 20 cm as the reserved deformation laver.展开更多
The an thors developed a new composite cement base material by mixing the high tenacity polypropylene （coarse） fiber in plain cement base for the cement-layer-spray technology. By studying the key parameters of the ...The an thors developed a new composite cement base material by mixing the high tenacity polypropylene （coarse） fiber in plain cement base for the cement-layer-spray technology. By studying the key parameters of the fiber dosage, the spray layer thickness, and the fiber reinforced concrete injection time, etc. It is found that the ideal volume ratio of polypropylene （crude） fiber is 0.8% （V/V）, and the secondary lining fiber concrete spraying should start when the shrinkage rate is lower than 0.5 mm/d, and the optimal thickness of shotcrete is 120 mm. The supporting effects and the economic benefits were studied using a real project practice, and the result obtained can be a good reference for practical applications of this new supporting material in the future.展开更多
Coal roadway support is the foundation and strong guarantee of safe coal production. With the FLAC3D numerical simulation, the roadway fulllength anchor support mechanism was studied, and the full-length anchor forcet...Coal roadway support is the foundation and strong guarantee of safe coal production. With the FLAC3D numerical simulation, the roadway fulllength anchor support mechanism was studied, and the full-length anchor forcetransferring mechanism and stressfield distribution formed by roadway surrounding rocks were analyzed, which will provide a scientific basis for a support technology in large-section roadways under complicated geological conditions and lay a foundation for the popularization and application of a full-length anchor support system under special geological conditions.展开更多
A mechanical model to control the top-coal deformation is established in accordance with the structural characters of the gob-side entry surrounding rock for the fully-mechanic top-coal caving; the analytical solution...A mechanical model to control the top-coal deformation is established in accordance with the structural characters of the gob-side entry surrounding rock for the fully-mechanic top-coal caving; the analytical solution of top coal roof-sag curve is deduced with Winkler elastic foundation beam model. By means of a calculating and analytic program, the top coal roof-sag values are calculated under the conditions of different supporting intensities, widths of narrow pillars and stiffness of top coal; meanwhile, the relationship between the roof-sag values and supporting intensity, width of narrow pillars and stiffness of top coal is analyzed as well. With the actual situation of the gob-side entry taken into consideration, the parameters of top-coal control are determined and a supporting plan is proposed for the top-coal control,which is proved to be reliable and effective by on-site verification. Some theoretical guidance and advice are put forward for the top-coal deformation control in gob-side entry for fully mechanized top-coal caving face.展开更多
A reasonable unsupported roof distance(URD) when advancing underground coal mine roadways can contribute greatly to safe and rapid roadway development.A mechanical model of the roof,using the relationship between the ...A reasonable unsupported roof distance(URD) when advancing underground coal mine roadways can contribute greatly to safe and rapid roadway development.A mechanical model of the roof,using the relationship between the roof stress distribution and URD,obtained by the difference method,and roof stability according to the in-situ roof stress and rock mass strength was developed.We subsequently designed a proper range of URD,developed a testing method of URD with the function of mining protection,evaluated roof stability through analyzing the test data and then determined a reasonable URD.Considering the factors of the geological conditions,the immediate roof stability and the efficiency of the labor arrangement system,the URD of the advancing roadway of 9802 working face in Zhangshuanglou coal mine was determined to be 6 m using the proposed method.The results show that,when a 2 m length of roadway was reinforced by temporary support and high pre-stressed bolt support after the roadway advancement of 6 m per cycle,the speed and the security of the roadway development can be achieved and the advance rate can reach more than 400 m per month.展开更多
In order to optimize gob-side entry in fully-mechanized working face in moderate-thick-coal seams, we adopt a new attempt to pack roadside by pumping ordinary concrete, which is very important for the development of g...In order to optimize gob-side entry in fully-mechanized working face in moderate-thick-coal seams, we adopt a new attempt to pack roadside by pumping ordinary concrete, which is very important for the development of gob-side entry technology. The concrete has a long initial setting time and a low initial strength. So it is difficult to control the surrounding rock. In this paper, we analyze the effect of using roadside cable to reinforce supporting in gob-side entry surrounding rock controlling based on elas-tic-plastic and material mechanics knowledge. And then we propose a scheme that cable is used to reinforce roadside supporting and a single hydraulic prop is used as the temporary supporting in gob side. Using the numerical simulation software FLAC2D, we numerically simulated supporting scheme. Results of both the 2D modeling and the industrial test on No.3117 face in Jingang Mine prove that the scheme is feasible. The results show that the technology of protecting the roadway in gob-entry retained efficiently make up the deficiency of roadside packing with ordinary concrete, effectively control the roof strata and acquire a good result of retaining roadway.展开更多
For the engineering geology conditions of bad mine roadway roof and floor lithology in extremely weak cemented strata, the best section shape of the roadway is determined from the study of tunnel surrounding rock disp...For the engineering geology conditions of bad mine roadway roof and floor lithology in extremely weak cemented strata, the best section shape of the roadway is determined from the study of tunnel surrounding rock displacement, plastic zone and stress distribution in rectangular, circle arch and arch wall sections, respectively. Based on the mining depth and thickness of the coal seam, roadway support technology solutions with different buried depth and thickness of coal seam are proposed. Support schemes are amended and optimized in time through monitoring data of the deformation of roadway, roof separation, l-beam bracket, bolt and anchor cable force to ensure the long-term stability and security of the roadway surrounding rock and support structure. The monitoring results show that mine roadway support schemes for different buried depth and section can be adapted to the characteristics of ground pressure and deformation of the surrounding rock in different depth well, effectively control the roadway surrounding rock deformation and the floor heave and guarantee the safety of construction and basic stability of surrounding rock and support structure.展开更多
In order to determine how a roadway withstands a momentum wave and determinethe extent of damage to rock surrounding the roadway under different force wavepeak impacts,the roadway dynamic response state was analysed u...In order to determine how a roadway withstands a momentum wave and determinethe extent of damage to rock surrounding the roadway under different force wavepeak impacts,the roadway dynamic response state was analysed using numerical simulationmethod.The roadway's critical peak force wave and fracture region under dynamicwave action were put forward.It is concluded that the method has practical value to roadwaysupport and rockburst prevention.展开更多
基金provided by the National Basic Research Program of China (No. 2007CB209408)the National Natural Science Foundation of China (No. 51074166)the Research Innovation Program for College Graduates of Jiangsu (No.CX098B_108Z)
文摘Based on the characteristics of the deep circular tunnel, the surrounding rock was divided into three regions： the cracked region, the plastic region and the viscoelastic region. The process of rock stress deformation and change was divided into three stages after the roadway excavation. By using the elastic-plastic mechanics theory, the analytical solutions of the surrounding stress and displacement at different stages and the radii of cracked and plastic regions were formulated. We additionally explained the surrounding rock stress and displacement which appeared in practical project. Simultaneously, based on the problem which emerged from a mine in Xuzhou during the excavating process of rock roadway＇s transport, we got the theoretical solutions for the stress and displacement in the process of rock roadway＇s excavation and considered that the broken area of rock roadway was largely loosing circle. The results indicate that according to the rheological characteristics of surrounding rock, in the primeval excavation of rock roadway, we should increase the length of anchor bolt and cooperate it with anchor nets cable-U steel supporting frame. In addition, when the deformation rate of the surrounding rock is descending after the 15 days＇ excavation, we should use the ＂three anchor＂ supporting method （anchor bolt spray, anchor note and anchor rove） and set aside about 20 cm as the reserved deformation laver.
文摘The an thors developed a new composite cement base material by mixing the high tenacity polypropylene （coarse） fiber in plain cement base for the cement-layer-spray technology. By studying the key parameters of the fiber dosage, the spray layer thickness, and the fiber reinforced concrete injection time, etc. It is found that the ideal volume ratio of polypropylene （crude） fiber is 0.8% （V/V）, and the secondary lining fiber concrete spraying should start when the shrinkage rate is lower than 0.5 mm/d, and the optimal thickness of shotcrete is 120 mm. The supporting effects and the economic benefits were studied using a real project practice, and the result obtained can be a good reference for practical applications of this new supporting material in the future.
基金Supported bythe National Natural Science Foundation of China （50904024） the State Key Laboratory Research Fund of Coal Resources and Mine Safety of China University of Mining ＆ Technology （10KF02） the Doctoral Fund of Henan Polytechnic University （B2009-66）
文摘Coal roadway support is the foundation and strong guarantee of safe coal production. With the FLAC3D numerical simulation, the roadway fulllength anchor support mechanism was studied, and the full-length anchor forcetransferring mechanism and stressfield distribution formed by roadway surrounding rocks were analyzed, which will provide a scientific basis for a support technology in large-section roadways under complicated geological conditions and lay a foundation for the popularization and application of a full-length anchor support system under special geological conditions.
基金funded by the National Natural Science Foundation of China(No.51374201,51323004)the State Key Development Program for Basic Research of China(No.2013CB227900)the College Student’s Program for Innovation of China University of Mining and Technology of China(No.201507)
文摘A mechanical model to control the top-coal deformation is established in accordance with the structural characters of the gob-side entry surrounding rock for the fully-mechanic top-coal caving; the analytical solution of top coal roof-sag curve is deduced with Winkler elastic foundation beam model. By means of a calculating and analytic program, the top coal roof-sag values are calculated under the conditions of different supporting intensities, widths of narrow pillars and stiffness of top coal; meanwhile, the relationship between the roof-sag values and supporting intensity, width of narrow pillars and stiffness of top coal is analyzed as well. With the actual situation of the gob-side entry taken into consideration, the parameters of top-coal control are determined and a supporting plan is proposed for the top-coal control,which is proved to be reliable and effective by on-site verification. Some theoretical guidance and advice are put forward for the top-coal deformation control in gob-side entry for fully mechanized top-coal caving face.
基金supported by the State Key Laboratory of Coal Resources and Sate Mining,China University of Mining and Technology (No.SKLCRSM13X07)the National Natural Science Foundation of China (No.51174195)+1 种基金Chinese National Programs for Fundamental Research and Development (No.2013CB227900)the Fundamental Research Funds for the Central Universities (No.2014XT01)
文摘A reasonable unsupported roof distance(URD) when advancing underground coal mine roadways can contribute greatly to safe and rapid roadway development.A mechanical model of the roof,using the relationship between the roof stress distribution and URD,obtained by the difference method,and roof stability according to the in-situ roof stress and rock mass strength was developed.We subsequently designed a proper range of URD,developed a testing method of URD with the function of mining protection,evaluated roof stability through analyzing the test data and then determined a reasonable URD.Considering the factors of the geological conditions,the immediate roof stability and the efficiency of the labor arrangement system,the URD of the advancing roadway of 9802 working face in Zhangshuanglou coal mine was determined to be 6 m using the proposed method.The results show that,when a 2 m length of roadway was reinforced by temporary support and high pre-stressed bolt support after the roadway advancement of 6 m per cycle,the speed and the security of the roadway development can be achieved and the advance rate can reach more than 400 m per month.
基金support from the National Nature Science Foundation of China (No50874124)
文摘In order to optimize gob-side entry in fully-mechanized working face in moderate-thick-coal seams, we adopt a new attempt to pack roadside by pumping ordinary concrete, which is very important for the development of gob-side entry technology. The concrete has a long initial setting time and a low initial strength. So it is difficult to control the surrounding rock. In this paper, we analyze the effect of using roadside cable to reinforce supporting in gob-side entry surrounding rock controlling based on elas-tic-plastic and material mechanics knowledge. And then we propose a scheme that cable is used to reinforce roadside supporting and a single hydraulic prop is used as the temporary supporting in gob side. Using the numerical simulation software FLAC2D, we numerically simulated supporting scheme. Results of both the 2D modeling and the industrial test on No.3117 face in Jingang Mine prove that the scheme is feasible. The results show that the technology of protecting the roadway in gob-entry retained efficiently make up the deficiency of roadside packing with ordinary concrete, effectively control the roof strata and acquire a good result of retaining roadway.
基金Financial support for this work, provided by the Major Program of the National Natural Science Foundation of China (Nos. 51174196 and 51204168)the Program for New Century Excellent Talents in University by Ministry of Education of China (No. NCET-07-0519)
文摘For the engineering geology conditions of bad mine roadway roof and floor lithology in extremely weak cemented strata, the best section shape of the roadway is determined from the study of tunnel surrounding rock displacement, plastic zone and stress distribution in rectangular, circle arch and arch wall sections, respectively. Based on the mining depth and thickness of the coal seam, roadway support technology solutions with different buried depth and thickness of coal seam are proposed. Support schemes are amended and optimized in time through monitoring data of the deformation of roadway, roof separation, l-beam bracket, bolt and anchor cable force to ensure the long-term stability and security of the roadway surrounding rock and support structure. The monitoring results show that mine roadway support schemes for different buried depth and section can be adapted to the characteristics of ground pressure and deformation of the surrounding rock in different depth well, effectively control the roadway surrounding rock deformation and the floor heave and guarantee the safety of construction and basic stability of surrounding rock and support structure.
基金Supported by the National Key Technology R&D Program in 11 th Five Years Plan of China(2006BAK03B06)
文摘In order to determine how a roadway withstands a momentum wave and determinethe extent of damage to rock surrounding the roadway under different force wavepeak impacts,the roadway dynamic response state was analysed using numerical simulationmethod.The roadway's critical peak force wave and fracture region under dynamicwave action were put forward.It is concluded that the method has practical value to roadwaysupport and rockburst prevention.
