Metal mineral resources play an indispensable role in the development of the national economy.Dynamic disasters in underground metal mines seriously threaten mining safety,which are major scientific and technological ...Metal mineral resources play an indispensable role in the development of the national economy.Dynamic disasters in underground metal mines seriously threaten mining safety,which are major scientific and technological problems to be solved urgently.In this article,the occurrence status and grand challenges of some typical dynamic disasters involving roof falling,spalling,collapse,large deformation,rockburst,surface subsidence,and water inrush in metal mines in China are systematically presented,the characteristics of mining-induced dynamic disasters are analyzed,the examples of dynamic disasters occurring in some metal mines in China are summarized,the occurrence mechanism,monitoring and early warning methods,and prevention and control techniques of these disasters are highlighted,and some new opinions,suggestions,and solutions are proposed simultaneously.Moreover,some shortcomings in current disaster research are pointed out,and the direction of efforts to improve the prevention and control level of dynamic disasters in China’s metal mines in the future is prospected.The integration of forward-looking key innovative theories and technologies in the abovementioned aspects will greatly enhance the cognitive level of disaster prevention and mitigation in China’s metal mining industry and achieve a significant shift from passive disaster relief to active disaster prevention.展开更多
The underground hydropower projects in Southwest China is characterized by large excavation sizes,high geostresses,complicated geological conditions and multiple construction processes.Various disasters such as collap...The underground hydropower projects in Southwest China is characterized by large excavation sizes,high geostresses,complicated geological conditions and multiple construction processes.Various disasters such as collapses,large deformations,rockbursts are frequently encountered,resulting in serious casualties and huge economic losses.This review mainly presents some representative results on microseismic(MS)monitoring and forecasting for disasters in hydropower underground engineering.First,a set of new denoising,spectral analysis,and location methods were developed for better identification and location of MS signals.Then,the tempo-spatial characteristics of MS events were analyzed to understand the relationship between field construction and damages of surrounding rocks.Combined with field construction,geological data,numerical simulation and parametric analysis of MS sources,the focal mechanism of MS events was revealed.A damage constitutive model considering MS fracturing size was put forward and feedback analysis considering the MS damage of underground surrounding rocks was conducted.Next,an MS multi-parameter based risk assessment and early warning method for dynamic disasters were proposed.The technology for control of the damage and deformation of underground surrounding rocks was proposed for underground caverns.Finally,two typical underground powerhouses were selected as case studies.These achievements can provide significant references for prevention and control of dynamic disasters for underground engineering with similar complicated geological conditions.展开更多
The study of the dynamic disaster mechanism of coal and gas outburst two-phase flow is crucial for improving disaster reduction and rescue ability of coal mine outburst accidents.An outburst test in a T-shaped roadway...The study of the dynamic disaster mechanism of coal and gas outburst two-phase flow is crucial for improving disaster reduction and rescue ability of coal mine outburst accidents.An outburst test in a T-shaped roadway was conducted using a self-developed large-scale outburst dynamic disaster test system.We investigated the release characteristics of main energy sources in coal seam,and obtained the dynamic characteristics of outburst two-phase flow in a roadway.Additionally,we established a formation model for outburst impact flow and a model for its flow in a bifurcated structure.The results indicate that the outburst process exhibits pulse characteristics,and the rapid destruction process of coal seam and the blocking state of gas flow are the main causes of the pulse phenomenon.The outburst energy is released in stages,and the elastic potential energy is released in the vertical direction before the horizontal direction.In a straight roadway,the impact force oscillates along the roadway.With an increase in the solid–gas ratio,the two-phase flow impact force gradually increases,and the disaster range extends from the middle of the roadway to the coal seam.In the area near the coal seam,the disaster caused by the two-phase flow impact is characterized by intermittent recovery.In a bifurcated roadway,the effect of impact airflow on impact dynamic disaster is much higher than that of two-phase flow,and the impact force tends to weaken with increasing solid-gas ratio.The impact force is asymmetrically distributed;it is higher on the left of the bifurcated roadway.With an increase in the solid-gas ratio,the static pressure rapidly decreases,and the bifurcated structure accelerates the attenuation of static pressure.Moreover,secondary acceleration is observed when the shock wave moves along the T-shaped roadway,indicating that the bifurcated structure increases the shock wave velocity.展开更多
In order to solve the problem that current theory models cannot accurately describe thick-hard roof(THR)elastic energy and assess the mine tremor disasters,a theoretical method,a Timoshenko beam theory on Winkler foun...In order to solve the problem that current theory models cannot accurately describe thick-hard roof(THR)elastic energy and assess the mine tremor disasters,a theoretical method,a Timoshenko beam theory on Winkler foundation was adopted to establish the THR’s periodic breaking model.The superposition principle was used for this complex model to derive the calculation formulas of the elastic energy and impact load on hydraulic supports.Then,the influence of roof thickness h,cantilever length L_(1),and load q on THR’s elastic energy and impact load was analyzed.And,the effect of mine tremor disasters was assessed.Finally,it is revealed that:(1)The THR’s elastic energy U exhibits power-law variations,with the fitted relationships U=0.0096L_(1)^(3.5866^),U=5943.9h^(-1.935),and U=21.049q^(2).(2)The impact load on hydraulic supports F_(ZJ) increases linearly with an increase in the cantilever length,thickness,and applied load.The fitted relationships are F_(ZJ)=1067.3L_(1)+6361.1,F_(ZJ)=125.89h+15100,and F_(ZJ)=10420q+3912.6.(3)Ground hydraulic fracturing and liquid explosive deep-hole blasting techniques effectively reduce the THR’s cantilever length at periodic breakages,thus eliminating mine tremor disasters.展开更多
In order to explore the control effect of backfill mining on dynamic disasters under special geological mining conditions of overlying thick magmatic rock(TMR),a three-dimensional numerical model of a panel of one sid...In order to explore the control effect of backfill mining on dynamic disasters under special geological mining conditions of overlying thick magmatic rock(TMR),a three-dimensional numerical model of a panel of one side goaf in Yangliu coal mine with double-yield backfill material constitutive model was developed.The simulation results were then compared with field monitoring data.The dynamic disaster control effect of both caving and backfill mining was analyzed in three different aspects,i.e.,displacement field,stress field and energy field.The results show that in comparison to the full caving mining method,the bearing capacity of the goaf after backfilling was enhanced,the backfill mining can effectively reduce the stress and energy accumulated in the coal/rock body,and the backfill mining eliminates the further moving space of TMR and prevents its sudden rupture.Before TMR fracture,the subsidence displacement of TMR was reduced by 65.3%,the front abutment stress of panel decreased by 9.4%on average and the high energy concentration zone around panel was also significantly reduced.Overall,the results of this study provide deeper insights into the control of dynamic disasters by backfill mining in mines.展开更多
The rupture and movement scope of overlying strata upon the longwall mining face increased sharply as the exploitation scale and degree growing recently,and the spatial structure formed by fractured strata became much...The rupture and movement scope of overlying strata upon the longwall mining face increased sharply as the exploitation scale and degree growing recently,and the spatial structure formed by fractured strata became much more complex.The overlying strata above the working face and adjacent gobs would affect each other and move cooperatively because small pillar can hardly separate the connection of overlying strata between two workfaces,which leads to mining seismicity in the gob and induces rockburst disaster that named spatial structure instability rockburst in this paper.Based on the key stratum theory,the F-structure model was established to describe the overlying strata characteristic and rockburst mechanism of workface with one side of gob and the other side un-mined solid coal seam.The results show that F-structure in the gob will re-active and loss stability under the influence of neighboring mining,and fracture and shear slipping in the process of instability is the mechanism of the seismicity in the gob.The F-structure was divided into two categories that short-arm F and long-arm F structure based on the state of strata above the gob.We studied the underground pressure rules of different F-structure and instability mechanism,thus provide the guide for prevention and control of the F-structure spatial instability rockburst.The micro-seismic system is used for on-site monitoring and researching the distribution rules of seismic events,the results confrmed the existence and correct of F-spatial structure.At last specialized methods for prevention seismicity and rockburst induced by F-structure instability are proposed and applied in Huating Coal Mine.展开更多
Efcient and accurate monitoring and early warning of coal dynamic disaster and other disasters can provide guarantee for the efcient operation of mine transportation system.However,the traditional threshold early warn...Efcient and accurate monitoring and early warning of coal dynamic disaster and other disasters can provide guarantee for the efcient operation of mine transportation system.However,the traditional threshold early warning method often fails to warning some accidents.To address above issues,a new early warning method was proposed based on"quiet period"phenomenon of AE and EMR during fracture.It is found that,a"quiet period"of AE and EMR was present before the load reaches the peak stress,which could be used as one of the precursors to warn the imminent failure of coal and rock specimens.MS and AE signals increased abnormally followed by the phenomenon of"quiet period"before the occurrence of coal dynamic disaster on site,and the decrease of MS events in the"quiet period"is about 57%–88%compared with that in previous abnormal increase stage.During the damage evolution of coal and rock,"quiet period"phenomenon usually occurred at 85%–90%of the peak stress,where the slope of damage parameter curve is almost zero.The"quiet period"of the AE-EMR signals and the low change rate of damage parameter before failure provide a theoretical foundation for the coal dynamic disaster warning based on the"quiet period"precursor found in MS-AE-EMR monitoring system.These fndings will help reduce the number of under-reported events and improve early warning accuracy.展开更多
Marine dynamic disasters,including storm surges,huge waves,and sea ice,are the most harmful natural disasters aff ecting coastal countries in the world.Under the infl uence of global climate change,the mechanisms,freq...Marine dynamic disasters,including storm surges,huge waves,and sea ice,are the most harmful natural disasters aff ecting coastal countries in the world.Under the infl uence of global climate change,the mechanisms,frequencies,and damage severity of marine dynamic disasters are exhibiting new characteristics.The enormity,unpredictability,and chain eff ects of these disasters have become increasingly prominent,and the losses endured by coastal countries around the world have been increasing year by year.Therefore,the prediction of,risk assessment for,and emergency response to marine dynamic disasters are important issues for disaster prevention and mitigation worldwide.展开更多
The gas cooperative control model combined local pressure-relief with regional pressure-reliet was estaonsnea, based on the theory of multi-parameters cooperative. For the status of high gas contents, high in-situ str...The gas cooperative control model combined local pressure-relief with regional pressure-reliet was estaonsnea, based on the theory of multi-parameters cooperative. For the status of high gas contents, high in-situ stress and low-permeability of Ji-15 seam of No.12 coal mine in Pingmei Group. The law of detonation wave propagation and ground-stress change distribution were simulated by means of the finite element analysis software. The technology of high-low-blasting, composed of high blasting(deep crossing hole controlled hydraulic blasting) and low blasting (special roadway deep hole controlled blasting) were developed. The research shows that around control hole produce maximum tension fracture failure, and result in directional and controlled Masting, when the distance between control hole and blasting hole is 1.2 m. The theory makes blasting force and hydraulic force advantage superimpose, which raises the effect of pressure relief and permeability enhancements compared with general blasting. High blasting influence radius and low blasting influence radius superimposed with each other, that prevents methane dynamic disaster. The result of type approval test shows that the technology can increase gas permeability as high as 22.7-36.2 ratio, decrease gas pressure from 2.85 MPa to 0.30 MPa, increase drilling influence radius to about 9 m. The technology realizes regional overall permeability improvement, that provides a new technical measure for methane dynamic disaster prevention.展开更多
Further evidences show that most mining dynamic disasters are mainly oc- curred nearby NNE and near SN geological structures.In-situ stress measurement in Fuxin basin shows that the orientation of major compressed str...Further evidences show that most mining dynamic disasters are mainly oc- curred nearby NNE and near SN geological structures.In-situ stress measurement in Fuxin basin shows that the orientation of major compressed stress is near EW.At this stress field,geological structures with deferent strike have deferent stress state and dis- place mode.NNE and near SN geological structures are compressed to thrust and come into being high stress zone.NWW and NEE geological structures are tensile to separate and not prone to being low stress zone.NW structure is intervenient of them.So NEE and near SN structures are easy to occurre mining dynamic disasters and NWW and NEE structures is 'safety' comparatively.The mining dynamic disaster is controlled by stress state of geologic structure,which is determined by its strike.展开更多
Introduced the coal and rock AE propagation rule,wave guide fixing technics onAE sensors,and AE forecasting coal and rock disaster on the scene and so on,The coaland rock AE propagation rule that follows the exponent ...Introduced the coal and rock AE propagation rule,wave guide fixing technics onAE sensors,and AE forecasting coal and rock disaster on the scene and so on,The coaland rock AE propagation rule that follows the exponent attenuation function on different AEfrequencies,different quality factors and different propagation distances were analyzedand deduced by theory,numerical simulation,and by actual experiment.Consequently,itwas deduced that the coal and rock AE propagation rule follows the exponent attenuationfunction.Based on the correlative theory of wave dynamics and AE sensor,the AE waveguide propagation mechanical model on the sensor fixing manner is found,and the relationsof displacement and speed and acceleration between the AE signal source and theAE signal receiving terminal are presented.The effect of the AE sensor fixing manners oncoal and rock surfaces,coal and rock bottoms and wave guides were studied by actualexperiment.For the results,the effect of the AE sensor fixing manner on wave guides isbetter than on coal and rock surfaces,and was equivalent to the fixing manner on coal androck bottoms.Based on the above study results,actual coal and rock dynamistic disasterswere successfully forecasted.展开更多
The man-induced sediment disaster includes material erosion, transportation and accumulation by human activities. It possesses special attribute in sociology and disaster science. In accordance with human activities, ...The man-induced sediment disaster includes material erosion, transportation and accumulation by human activities. It possesses special attribute in sociology and disaster science. In accordance with human activities, geomorphologic location, behavior and particular, the man-induced sediment disaster can be divided into 4 types: the drainage network, slope and gully, channel and plain-estuary-coastline. Each type includes erosion, transportation, accumulation, complexity and cascading. Based on human activity, geomorphology, sediment mechanics and catastrophology, the man-induced sediment disaster is characterized as follows: (1) accelerating tendency with geographical zoning back-ground; (2) non-order characters by blind action without special technical training; (3) gradually and sharply changing with human environment vibration; and (4) complexity and non-linear figure, etc. One of the reasons leading to man-induced sediment disaster is human environment vibration.展开更多
In this study, we systematically studied the occurrence regularity of in situ stress in the Pingdingshan mine. The critical criterion model of coal-rock destabilization was established based on the theoretical framewo...In this study, we systematically studied the occurrence regularity of in situ stress in the Pingdingshan mine. The critical criterion model of coal-rock destabilization was established based on the theoretical framework of fracture mechanics. Furthermore, we analyzed the coupling destabilization mechanism of in situ stress and gas and studied the influence of the variation between original rock stress and mining-induced stress on the critical criterion. Through field experiments and applications, we established a three-dimensional gas drainage technology system for areas with a large mining height and long work face. Based on our research, a demonstration project was developed for deep mine dynamic disaster control. The technical system included the arrangement and optimization of pre-drainage holes along the coal seam, technology, and optimization of gas drainage through the bottom drainage tunnel and upper corner, gas drainage technology through sieve tubes, and a two plugging with one injection under pressure sealing technology. The implementation of the demonstration project effectively reduced the gas content and pressure of the coal seam in the deep mine, and the project increased the critical strength of the instability and failure of coal and rock.展开更多
Coalburst is one of the most serious disasters that threaten the safe production of coal mines, and this disaster is particularly serious in China. This paper presents an overview of coalbursts in China since 1980s. F...Coalburst is one of the most serious disasters that threaten the safe production of coal mines, and this disaster is particularly serious in China. This paper presents an overview of coalbursts in China since 1980s. From the "stress and energy" and "regional and local" perspectives, the achievements in the theory, practice and management of coalbursts in China are systematically summarized. A theoretical system of coalbursts has been formed to reveal the deformational behavior of coalbursts and explain the mechanism of coalbursts. The occurrence conditions of coalbursts are put forward and the critical stress is obtained. The stress index method for risk evaluation of coalbursts before mining is proposed, and the deformation localization prediction method of coalbursts is put forward. The relationship between energy release and absorption in the process of coalbursts is found, and the prevention and control methods of coalbursts, including the regional method, the local method and support, are presented. The safety evaluation index of coalburst prevention and control is put forward. The integrated prevention and control method for coal and gas outbursts is proposed. The prevention and control technology and equipment of coalbursts have also been developed. Amongst them, the distribution law of the critical stress in China coalburst mines is discovered. The technology and equipment for monitoring, prevention and control of coalbursts, as well as for integrated prevention and control of combined coalbursts and other disasters, have been developed. The energy-absorbing and coalburst-preventing support technology for roadways is invented, and key engineering parameters of coalburst prevention and control are pointed out. In China, coalburst prevention and control laws and standards have been developed. Technical standards for coalbursts are formulated, statute and regulations for coal mines are established, and regulatory documents are promoted.展开更多
基金Project(52204084)supported by the National Natural Science Foundation of ChinaProject(FRF-IDRY-GD22-002)supported by the Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Research Funds for the Central Universities),China+2 种基金Project(QNXM20220009)supported by the Fundamental Research Funds for the Central Universities and the Youth Teacher International Exchange and Growth Program,ChinaProjects(2022YFC2905600,2022YFC3004601)supported by the National Key R&D Program of ChinaProject(2023XAGG0061)supported by the Science,Technology&Innovation Project of Xiongan New Area,China。
文摘Metal mineral resources play an indispensable role in the development of the national economy.Dynamic disasters in underground metal mines seriously threaten mining safety,which are major scientific and technological problems to be solved urgently.In this article,the occurrence status and grand challenges of some typical dynamic disasters involving roof falling,spalling,collapse,large deformation,rockburst,surface subsidence,and water inrush in metal mines in China are systematically presented,the characteristics of mining-induced dynamic disasters are analyzed,the examples of dynamic disasters occurring in some metal mines in China are summarized,the occurrence mechanism,monitoring and early warning methods,and prevention and control techniques of these disasters are highlighted,and some new opinions,suggestions,and solutions are proposed simultaneously.Moreover,some shortcomings in current disaster research are pointed out,and the direction of efforts to improve the prevention and control level of dynamic disasters in China’s metal mines in the future is prospected.The integration of forward-looking key innovative theories and technologies in the abovementioned aspects will greatly enhance the cognitive level of disaster prevention and mitigation in China’s metal mining industry and achieve a significant shift from passive disaster relief to active disaster prevention.
基金The authors are grateful for the financial support from the National Natural Science Foundation of China(Grant Nos.42177143,42277461)the Science Foundation for Distinguished Young Scholars of Sichuan Province(Grant No.2020JDJQ0011).Thanks to the Chn Energy Dadu River Hydropower Development Co.,Ltd,China Three Gorges Construction Engineering Corporation,Yalong River Hydropower Development Company,Ltd,Power China Chengdu Engineering Co.,Ltd,Power China Northwest Engineering Co.,Ltd,Power China Sinohydro Bureau 7 Co.,Ltd,China Gezhouba Group No.1 Engineering Co.,Ltd.,and the 5th Engineering Co.,Ltd.of China Railway Construction Bridge Engineering Bureau Group for the support and assistance.
文摘The underground hydropower projects in Southwest China is characterized by large excavation sizes,high geostresses,complicated geological conditions and multiple construction processes.Various disasters such as collapses,large deformations,rockbursts are frequently encountered,resulting in serious casualties and huge economic losses.This review mainly presents some representative results on microseismic(MS)monitoring and forecasting for disasters in hydropower underground engineering.First,a set of new denoising,spectral analysis,and location methods were developed for better identification and location of MS signals.Then,the tempo-spatial characteristics of MS events were analyzed to understand the relationship between field construction and damages of surrounding rocks.Combined with field construction,geological data,numerical simulation and parametric analysis of MS sources,the focal mechanism of MS events was revealed.A damage constitutive model considering MS fracturing size was put forward and feedback analysis considering the MS damage of underground surrounding rocks was conducted.Next,an MS multi-parameter based risk assessment and early warning method for dynamic disasters were proposed.The technology for control of the damage and deformation of underground surrounding rocks was proposed for underground caverns.Finally,two typical underground powerhouses were selected as case studies.These achievements can provide significant references for prevention and control of dynamic disasters for underground engineering with similar complicated geological conditions.
基金This work was supported by the National Natural Science Foundation of China(Nos.51874055,52074047,and 52064016).
文摘The study of the dynamic disaster mechanism of coal and gas outburst two-phase flow is crucial for improving disaster reduction and rescue ability of coal mine outburst accidents.An outburst test in a T-shaped roadway was conducted using a self-developed large-scale outburst dynamic disaster test system.We investigated the release characteristics of main energy sources in coal seam,and obtained the dynamic characteristics of outburst two-phase flow in a roadway.Additionally,we established a formation model for outburst impact flow and a model for its flow in a bifurcated structure.The results indicate that the outburst process exhibits pulse characteristics,and the rapid destruction process of coal seam and the blocking state of gas flow are the main causes of the pulse phenomenon.The outburst energy is released in stages,and the elastic potential energy is released in the vertical direction before the horizontal direction.In a straight roadway,the impact force oscillates along the roadway.With an increase in the solid–gas ratio,the two-phase flow impact force gradually increases,and the disaster range extends from the middle of the roadway to the coal seam.In the area near the coal seam,the disaster caused by the two-phase flow impact is characterized by intermittent recovery.In a bifurcated roadway,the effect of impact airflow on impact dynamic disaster is much higher than that of two-phase flow,and the impact force tends to weaken with increasing solid-gas ratio.The impact force is asymmetrically distributed;it is higher on the left of the bifurcated roadway.With an increase in the solid-gas ratio,the static pressure rapidly decreases,and the bifurcated structure accelerates the attenuation of static pressure.Moreover,secondary acceleration is observed when the shock wave moves along the T-shaped roadway,indicating that the bifurcated structure increases the shock wave velocity.
基金supported by the Chongqing Postdoctoral Special Support(No.2022CQBSHTB1022)the Autonomous General Projects of State Key Laboratory of Coal Mine Disaster Dynamics and Control(No.2011DA105287-MS202209)the State Key Laboratory of Coal Mine Disaster Dynamics and Control Faces the 2030 project(No.2011DA105287-MX2030-202002).
文摘In order to solve the problem that current theory models cannot accurately describe thick-hard roof(THR)elastic energy and assess the mine tremor disasters,a theoretical method,a Timoshenko beam theory on Winkler foundation was adopted to establish the THR’s periodic breaking model.The superposition principle was used for this complex model to derive the calculation formulas of the elastic energy and impact load on hydraulic supports.Then,the influence of roof thickness h,cantilever length L_(1),and load q on THR’s elastic energy and impact load was analyzed.And,the effect of mine tremor disasters was assessed.Finally,it is revealed that:(1)The THR’s elastic energy U exhibits power-law variations,with the fitted relationships U=0.0096L_(1)^(3.5866^),U=5943.9h^(-1.935),and U=21.049q^(2).(2)The impact load on hydraulic supports F_(ZJ) increases linearly with an increase in the cantilever length,thickness,and applied load.The fitted relationships are F_(ZJ)=1067.3L_(1)+6361.1,F_(ZJ)=125.89h+15100,and F_(ZJ)=10420q+3912.6.(3)Ground hydraulic fracturing and liquid explosive deep-hole blasting techniques effectively reduce the THR’s cantilever length at periodic breakages,thus eliminating mine tremor disasters.
基金Project(2017YFC1503100)supported by the National Key Research and Development Program of ChinaProjects(51974062,41672301,51811530312)supported by the National Natural Science Foundation of ChinaProject(N180101028)supported by the Fundamental Research Funds for the Central Universities,China。
文摘In order to explore the control effect of backfill mining on dynamic disasters under special geological mining conditions of overlying thick magmatic rock(TMR),a three-dimensional numerical model of a panel of one side goaf in Yangliu coal mine with double-yield backfill material constitutive model was developed.The simulation results were then compared with field monitoring data.The dynamic disaster control effect of both caving and backfill mining was analyzed in three different aspects,i.e.,displacement field,stress field and energy field.The results show that in comparison to the full caving mining method,the bearing capacity of the goaf after backfilling was enhanced,the backfill mining can effectively reduce the stress and energy accumulated in the coal/rock body,and the backfill mining eliminates the further moving space of TMR and prevents its sudden rupture.Before TMR fracture,the subsidence displacement of TMR was reduced by 65.3%,the front abutment stress of panel decreased by 9.4%on average and the high energy concentration zone around panel was also significantly reduced.Overall,the results of this study provide deeper insights into the control of dynamic disasters by backfill mining in mines.
基金Financial support for this work, provided by the National Basic Research Program of China (No. 2010CB226805)the National Natural Science Foundation of China (No. 51174285)+1 种基金the Twelfth Five-Year National Key Technology R&D Program (No. 2012BAK09B01)the Independent Foundation of State Key Laboratory of Coal Resources and Mine Safety (No. SKLCRSM10X05) are gratefully acknowledged
文摘The rupture and movement scope of overlying strata upon the longwall mining face increased sharply as the exploitation scale and degree growing recently,and the spatial structure formed by fractured strata became much more complex.The overlying strata above the working face and adjacent gobs would affect each other and move cooperatively because small pillar can hardly separate the connection of overlying strata between two workfaces,which leads to mining seismicity in the gob and induces rockburst disaster that named spatial structure instability rockburst in this paper.Based on the key stratum theory,the F-structure model was established to describe the overlying strata characteristic and rockburst mechanism of workface with one side of gob and the other side un-mined solid coal seam.The results show that F-structure in the gob will re-active and loss stability under the influence of neighboring mining,and fracture and shear slipping in the process of instability is the mechanism of the seismicity in the gob.The F-structure was divided into two categories that short-arm F and long-arm F structure based on the state of strata above the gob.We studied the underground pressure rules of different F-structure and instability mechanism,thus provide the guide for prevention and control of the F-structure spatial instability rockburst.The micro-seismic system is used for on-site monitoring and researching the distribution rules of seismic events,the results confrmed the existence and correct of F-spatial structure.At last specialized methods for prevention seismicity and rockburst induced by F-structure instability are proposed and applied in Huating Coal Mine.
基金supported by Grants from the National Natural Science Foundation of China(No.52004016)the Postdoctoral Research Foundation of China(No.2021M700371)+3 种基金the Major Science and Technology Innovation Project of Shandong Province(No.2019SDZY02)the Open Fund Project of Shaanxi Key Laboratory of Prevention and Control Technology for Coal Mine Water Hazard(No.2021SKMS05)Science and Technology Support Plan Project of Guizhou Province(No.[2021]515)The authors are grateful to the anonymous referees for their precious comments and suggestions.
文摘Efcient and accurate monitoring and early warning of coal dynamic disaster and other disasters can provide guarantee for the efcient operation of mine transportation system.However,the traditional threshold early warning method often fails to warning some accidents.To address above issues,a new early warning method was proposed based on"quiet period"phenomenon of AE and EMR during fracture.It is found that,a"quiet period"of AE and EMR was present before the load reaches the peak stress,which could be used as one of the precursors to warn the imminent failure of coal and rock specimens.MS and AE signals increased abnormally followed by the phenomenon of"quiet period"before the occurrence of coal dynamic disaster on site,and the decrease of MS events in the"quiet period"is about 57%–88%compared with that in previous abnormal increase stage.During the damage evolution of coal and rock,"quiet period"phenomenon usually occurred at 85%–90%of the peak stress,where the slope of damage parameter curve is almost zero.The"quiet period"of the AE-EMR signals and the low change rate of damage parameter before failure provide a theoretical foundation for the coal dynamic disaster warning based on the"quiet period"precursor found in MS-AE-EMR monitoring system.These fndings will help reduce the number of under-reported events and improve early warning accuracy.
基金the National Key Research and Development Program of China’s “Severe marine dynamic disasters: causing mechanism, risk assessment, response technology, and demonstration application” project (No. 2016YFC1402000) for financial support
文摘Marine dynamic disasters,including storm surges,huge waves,and sea ice,are the most harmful natural disasters aff ecting coastal countries in the world.Under the infl uence of global climate change,the mechanisms,frequencies,and damage severity of marine dynamic disasters are exhibiting new characteristics.The enormity,unpredictability,and chain eff ects of these disasters have become increasingly prominent,and the losses endured by coastal countries around the world have been increasing year by year.Therefore,the prediction of,risk assessment for,and emergency response to marine dynamic disasters are important issues for disaster prevention and mitigation worldwide.
基金Supported by the Major Project of Chinese National Program for Fundamental Research and Development (973) (2011CB201205) the Nature Science Foundation of China (50804048)
文摘The gas cooperative control model combined local pressure-relief with regional pressure-reliet was estaonsnea, based on the theory of multi-parameters cooperative. For the status of high gas contents, high in-situ stress and low-permeability of Ji-15 seam of No.12 coal mine in Pingmei Group. The law of detonation wave propagation and ground-stress change distribution were simulated by means of the finite element analysis software. The technology of high-low-blasting, composed of high blasting(deep crossing hole controlled hydraulic blasting) and low blasting (special roadway deep hole controlled blasting) were developed. The research shows that around control hole produce maximum tension fracture failure, and result in directional and controlled Masting, when the distance between control hole and blasting hole is 1.2 m. The theory makes blasting force and hydraulic force advantage superimpose, which raises the effect of pressure relief and permeability enhancements compared with general blasting. High blasting influence radius and low blasting influence radius superimposed with each other, that prevents methane dynamic disaster. The result of type approval test shows that the technology can increase gas permeability as high as 22.7-36.2 ratio, decrease gas pressure from 2.85 MPa to 0.30 MPa, increase drilling influence radius to about 9 m. The technology realizes regional overall permeability improvement, that provides a new technical measure for methane dynamic disaster prevention.
基金the Major State Basic Research Development Program of China"973"Program(2005CB221501)the General Project of the National Natural Science Foundation of PR China(50574047)
文摘Further evidences show that most mining dynamic disasters are mainly oc- curred nearby NNE and near SN geological structures.In-situ stress measurement in Fuxin basin shows that the orientation of major compressed stress is near EW.At this stress field,geological structures with deferent strike have deferent stress state and dis- place mode.NNE and near SN geological structures are compressed to thrust and come into being high stress zone.NWW and NEE geological structures are tensile to separate and not prone to being low stress zone.NW structure is intervenient of them.So NEE and near SN structures are easy to occurre mining dynamic disasters and NWW and NEE structures is 'safety' comparatively.The mining dynamic disaster is controlled by stress state of geologic structure,which is determined by its strike.
基金Supported by the Project of National Basic Research Program of China(973 Program)(2005CB221505)the Significant Project of National Natural Science Fund(50534080/E041503)the Project of Coal Mine Gas and Fire Hazard Prevention Major Lab in Henan Province(HKLGF200508)
文摘Introduced the coal and rock AE propagation rule,wave guide fixing technics onAE sensors,and AE forecasting coal and rock disaster on the scene and so on,The coaland rock AE propagation rule that follows the exponent attenuation function on different AEfrequencies,different quality factors and different propagation distances were analyzedand deduced by theory,numerical simulation,and by actual experiment.Consequently,itwas deduced that the coal and rock AE propagation rule follows the exponent attenuationfunction.Based on the correlative theory of wave dynamics and AE sensor,the AE waveguide propagation mechanical model on the sensor fixing manner is found,and the relationsof displacement and speed and acceleration between the AE signal source and theAE signal receiving terminal are presented.The effect of the AE sensor fixing manners oncoal and rock surfaces,coal and rock bottoms and wave guides were studied by actualexperiment.For the results,the effect of the AE sensor fixing manner on wave guides isbetter than on coal and rock surfaces,and was equivalent to the fixing manner on coal androck bottoms.Based on the above study results,actual coal and rock dynamistic disasterswere successfully forecasted.
基金Joint project by National Natural Science Foundation of China and the Ministry of Water Resources,No.59890200National Natural Science Foundation of China, No.48870008
文摘The man-induced sediment disaster includes material erosion, transportation and accumulation by human activities. It possesses special attribute in sociology and disaster science. In accordance with human activities, geomorphologic location, behavior and particular, the man-induced sediment disaster can be divided into 4 types: the drainage network, slope and gully, channel and plain-estuary-coastline. Each type includes erosion, transportation, accumulation, complexity and cascading. Based on human activity, geomorphology, sediment mechanics and catastrophology, the man-induced sediment disaster is characterized as follows: (1) accelerating tendency with geographical zoning back-ground; (2) non-order characters by blind action without special technical training; (3) gradually and sharply changing with human environment vibration; and (4) complexity and non-linear figure, etc. One of the reasons leading to man-induced sediment disaster is human environment vibration.
基金the National Natural Science Foundation of China(Grant No.51874053)the Scientific Research Foundation of State Key Laboratory of Coal Mine Disaster Dynamics and Control(No.2011DA105287-zd201804).
文摘In this study, we systematically studied the occurrence regularity of in situ stress in the Pingdingshan mine. The critical criterion model of coal-rock destabilization was established based on the theoretical framework of fracture mechanics. Furthermore, we analyzed the coupling destabilization mechanism of in situ stress and gas and studied the influence of the variation between original rock stress and mining-induced stress on the critical criterion. Through field experiments and applications, we established a three-dimensional gas drainage technology system for areas with a large mining height and long work face. Based on our research, a demonstration project was developed for deep mine dynamic disaster control. The technical system included the arrangement and optimization of pre-drainage holes along the coal seam, technology, and optimization of gas drainage through the bottom drainage tunnel and upper corner, gas drainage technology through sieve tubes, and a two plugging with one injection under pressure sealing technology. The implementation of the demonstration project effectively reduced the gas content and pressure of the coal seam in the deep mine, and the project increased the critical strength of the instability and failure of coal and rock.
基金This work was supported by the National Natural Science Foundation of China-Liaoning Joint Fund Key Project(Grant No.U1908222)the National Natural Science Foundation of China(Grant No.51774015).
文摘Coalburst is one of the most serious disasters that threaten the safe production of coal mines, and this disaster is particularly serious in China. This paper presents an overview of coalbursts in China since 1980s. From the "stress and energy" and "regional and local" perspectives, the achievements in the theory, practice and management of coalbursts in China are systematically summarized. A theoretical system of coalbursts has been formed to reveal the deformational behavior of coalbursts and explain the mechanism of coalbursts. The occurrence conditions of coalbursts are put forward and the critical stress is obtained. The stress index method for risk evaluation of coalbursts before mining is proposed, and the deformation localization prediction method of coalbursts is put forward. The relationship between energy release and absorption in the process of coalbursts is found, and the prevention and control methods of coalbursts, including the regional method, the local method and support, are presented. The safety evaluation index of coalburst prevention and control is put forward. The integrated prevention and control method for coal and gas outbursts is proposed. The prevention and control technology and equipment of coalbursts have also been developed. Amongst them, the distribution law of the critical stress in China coalburst mines is discovered. The technology and equipment for monitoring, prevention and control of coalbursts, as well as for integrated prevention and control of combined coalbursts and other disasters, have been developed. The energy-absorbing and coalburst-preventing support technology for roadways is invented, and key engineering parameters of coalburst prevention and control are pointed out. In China, coalburst prevention and control laws and standards have been developed. Technical standards for coalbursts are formulated, statute and regulations for coal mines are established, and regulatory documents are promoted.