Large-scale bed separation in bending strip upside cranny strip was brought by un-consistency of overlying strata subsidence movement due to under surface mining. Different characteristic of movement and deformation o...Large-scale bed separation in bending strip upside cranny strip was brought by un-consistency of overlying strata subsidence movement due to under surface mining. Different characteristic of movement and deformation of overlying strata and surface include periodic caving of bed separation interspaced along with work face mining. Conglomerate rock layer movement is the main power fountain of rock burst on the basis of locale observation. And rock burst moves periodically adapted to movement of deep conglomerate rock layer which had similar characteristic with main roof. Practice indicates this method that forecasting and prediction using correlation information of movement of strata and surface is feasible and has reference meaning for similar stope.展开更多
Movement and deformation of underground rock include vertical dislocation and horizontal deformation,and the energy released by mine earthquake can be calculated basing on deformation energy.So put forwards the predic...Movement and deformation of underground rock include vertical dislocation and horizontal deformation,and the energy released by mine earthquake can be calculated basing on deformation energy.So put forwards the prediction for degree and spread of mine earthquake according to the underground rock's movement and deformation.The actual number of times and spread of mine earthquake on site were greatly identical to the prediction.The practice proves the possibility of prediction for mine earthquake basing on the analysis of underground rock's movement and deformation,and sets up new approach of mine earthquake prediction.展开更多
In the 1960 s, America has entered a new historical period with recession in economy and increasingly bad social problem. Besides, Civil Rights Movement and women rights movement have been led by black people and wome...In the 1960 s, America has entered a new historical period with recession in economy and increasingly bad social problem. Besides, Civil Rights Movement and women rights movement have been led by black people and women for equal rights.With the development of these movements, the counter-cultural movement came into being, and the movement which represented a significant period in post-war youth cultural history was caused by the impending readjustment of social structure during the transition from industrial to post-industrial society in the 1960 s. American white middle class youth were disillusioned with the way their parent culture controlled the society and had no desire to become caught up in the machinery of social power themselves.The counter-cultural constituted a direct attack on the part of white middle class youth against the dominant ideological machinery set in place and maintained by its parent culture, and its influence has been maintained to the modern times. Except for the liberation of sex and drug, the most important symbol of the counter-culture is rock music. There is a close relationship between the counter-cultural movement and rock music. During the mid to late 1960 s rock music became a centrally significant medium for the dissemination of a range of social-political issues in counter-cultural movement. The period from the mid-1960 s to the early 1970 s represented the first time that popular music, a mass cultural form, had become a centrally significant medium for the dissemination of a range of sociopolitical issues, from US involvement in the Vietnam war to the Civil Rights Movements, to the rejection of western political and cultural ideology. As Eyerman and Jamison^([1])point out:‘Movement ideas, images,and feelings were disseminated in and through popular music and, at the same time, the movements of the times influenced developments, in both form and content, in popular music'.展开更多
Dynamic disasters,such as rock burst due to the breaking of large area stiff roof strata,are known to occur in the hard rock strata of coal mines.In this paper,mechanical models of the fracturing processes of thick ha...Dynamic disasters,such as rock burst due to the breaking of large area stiff roof strata,are known to occur in the hard rock strata of coal mines.In this paper,mechanical models of the fracturing processes of thick hard rock strata were established based on the thick plate theory and numerical simulations.The results demonstrated that,based on the fracture characteristics of the thick hard rock strata,four fracture models could be analyzed in detail,and the corresponding theoretical failure criteria were determined in detail.In addition,the influence of weak interlayer position on the fracture models and ground pressure of rock strata is deeply analyzed,and six numerical simulation schemes have been implemented.The results showed that the working face pressure caused by the independent movement of the lower layer is relatively low.The different fracture type of the thick hard rock strata had different demands on the working resistance of the hydraulic powered supports.The working resistance of the hydraulic powered supports required by the stratified movements was lower than that of the non-stratified movements.展开更多
Mountain hazards with large masses of rock blocks in motion – such as rock falls, avalanches and landslides – threaten human lives and structures. Dynamic fragmentation is a common phenomenon during the movement pro...Mountain hazards with large masses of rock blocks in motion – such as rock falls, avalanches and landslides – threaten human lives and structures. Dynamic fragmentation is a common phenomenon during the movement process of rock blocks in rock avalanche, due to the high velocity and impacts against obstructions. In view of the energy consumption theory for brittle rock fragmentation proposed by Bond, which relates energy to size reduction, a theoretical model is proposed to estimate the average fragment size for a moving rock block when it impacts against an obstruction. Then, different forms of motion are studied, with various drop heights and slope angles for the moving rock block. The calculated results reveal that the average fragment size decreases as the drop height increases, whether for free-fall or for a sliding or rolling rock block, and the decline in size is rapid for low heights and slow for increasing heights in the corresponding curves. Moreover, the average fragment size also decreases as the slope angle increases for a slidingrock block. In addition, a rolling rock block has a higher degree of fragmentation than a sliding rock block, even for the same slope angle and block volume. Finally, to compare with others' results, the approximate number of fragments is estimated for each calculated example, and the results show that the proposed model is applicable to a relatively isotropic moving rock block.展开更多
Two branches of Tangjiagou rock avalanche were triggered by Lushan earthquake in Sichuan Province,China on April 20th,2013.The rock avalanche has transported about 1500000 m3 of sandstone from the source area.Based on...Two branches of Tangjiagou rock avalanche were triggered by Lushan earthquake in Sichuan Province,China on April 20th,2013.The rock avalanche has transported about 1500000 m3 of sandstone from the source area.Based on discrete element modeling,this study simulates the deformation,failure and movement process of the rock avalanche.Under seismic loading,the mechanism and process of deformation,failure,and runout of the two branches are similar.In detail,the stress concentration occur firstly on the top of the mountain ridge,and accordingly,the tensile deformation appears.With the increase of seismic loading,the strain concentration zone extends in the forward and backward directions along the slipping surface,forming a locking segment.As a result,the slipping surface penetrates and the slide mass begin to slide down with high speed.Finally,the avalanche accumulates in the downstream and forms a small barrier lake.Modeling shows that a number of rocks on the surface exhibit patterns of horizontal throwing and vertical jumping under strong ground shaking.We suggest that the movement of the rock avalanche is a complicated process with multiple stages,including formation of the two branches,high-speed sliding,transformation into debris flows,further movement and collision,accumulation,and the final steady state.Topographic amplification effects are also revealed based on acceleration and velocity of special monitoring points.The horizontal and vertical runout distances of the surface materials are much greater than those of the internal materials.Besides,the sliding duration is also longer than that of the internal rock mass.展开更多
Based on outcrop, drilling, logging, geochemical analysis and seismic data, the karst landform and distribution of Permian volcanic rocks at the end of the sedimentary period of the Maokou Formation in the western Sic...Based on outcrop, drilling, logging, geochemical analysis and seismic data, the karst landform and distribution of Permian volcanic rocks at the end of the sedimentary period of the Maokou Formation in the western Sichuan Basin are examined, and their petroleum geological significance is discussed. Affected by normal faults formed in the early magmatic activities and extension tectonic background in the late sedimentary period of the Maokou Formation, a local karst shallow depression under the background of karst slope came up in the Jianyang area of the western Sichuan Basin, where the residual thickness of the Maokou Formation was thinner. Basic volcanic rocks like pyroclastic rock of eruptive facies, basalt of overflow facies, diabase porphyrite of intrusive facies and sedimentary tuff of volcanic sedimentary facies were formed after karstification. However, under the effects of faulting and karst paleogeomorphology, the volcanic rocks in different areas had different accumulation features. In the Jianyang area, with long eruption time, the volcanic rocks were thick and complex in lithology, and accumulated in the karst depressions. In the Zhongjiang-Santai area located in the karst slope, there’s no fault developed, only thin layers of basalt and sedimentary tuff turned up. The karst landform controls the build-up of thick explosive facies volcanic rocks and also the development of karst reservoirs in the Maokou Formation, and the western Sichuan area has oil and gas exploration potential in volcanic rocks and the Maokou Formation.展开更多
The SPOT image analysis in Muzaffarabad Azad Kashmir,northwest Himalayas,Pakistan reveals that the Kashmir earthquake 2005 triggered a number of coseismic mass movements along the hanging wall block of the Muzaffaraba...The SPOT image analysis in Muzaffarabad Azad Kashmir,northwest Himalayas,Pakistan reveals that the Kashmir earthquake 2005 triggered a number of coseismic mass movements along the hanging wall block of the Muzaffarabad Fault.The Neelidandi and Langarpura rock falls have been identified as two major reactivated mass movements with an estimated volume of 3.1 × 106m3and 5.76 × 106m3,respectively.The Neelidandi and Langarpura mass movements were initiated during earthquake in the direction of northwest-southeast extension and northeastsouthwest directed thrusting,respectively.The Neelidandi rock fall occurred in sheared cherty dolomites and limestones of the Cambrian Muzaffarabad Formation,whereas the Langarpura rock fall occurred in alternating clays,shales,claystones,siltstones and sandstones of the Miocene Murree Formation.These rock units along the fault are highly fractured and jointed.The geotechnical maps and geological longitudinal profiles show the relationship between the geometrical characteristics and mechanism of these mass movements.Their characteristics were analyzed according to the role of topographic,seismic,geological and tectonic factors.The steep topography,sheared rocks,lithology,coseismic uplift and strong ground shaking of the hanging wall block along Muzaffarabad Fault facilitated the gravity collapse of these mass movements.展开更多
文摘Large-scale bed separation in bending strip upside cranny strip was brought by un-consistency of overlying strata subsidence movement due to under surface mining. Different characteristic of movement and deformation of overlying strata and surface include periodic caving of bed separation interspaced along with work face mining. Conglomerate rock layer movement is the main power fountain of rock burst on the basis of locale observation. And rock burst moves periodically adapted to movement of deep conglomerate rock layer which had similar characteristic with main roof. Practice indicates this method that forecasting and prediction using correlation information of movement of strata and surface is feasible and has reference meaning for similar stope.
基金the Education Research Project of Liaoning(20060388)Liaoning Technology University Project(06A07)
文摘Movement and deformation of underground rock include vertical dislocation and horizontal deformation,and the energy released by mine earthquake can be calculated basing on deformation energy.So put forwards the prediction for degree and spread of mine earthquake according to the underground rock's movement and deformation.The actual number of times and spread of mine earthquake on site were greatly identical to the prediction.The practice proves the possibility of prediction for mine earthquake basing on the analysis of underground rock's movement and deformation,and sets up new approach of mine earthquake prediction.
文摘In the 1960 s, America has entered a new historical period with recession in economy and increasingly bad social problem. Besides, Civil Rights Movement and women rights movement have been led by black people and women for equal rights.With the development of these movements, the counter-cultural movement came into being, and the movement which represented a significant period in post-war youth cultural history was caused by the impending readjustment of social structure during the transition from industrial to post-industrial society in the 1960 s. American white middle class youth were disillusioned with the way their parent culture controlled the society and had no desire to become caught up in the machinery of social power themselves.The counter-cultural constituted a direct attack on the part of white middle class youth against the dominant ideological machinery set in place and maintained by its parent culture, and its influence has been maintained to the modern times. Except for the liberation of sex and drug, the most important symbol of the counter-culture is rock music. There is a close relationship between the counter-cultural movement and rock music. During the mid to late 1960 s rock music became a centrally significant medium for the dissemination of a range of social-political issues in counter-cultural movement. The period from the mid-1960 s to the early 1970 s represented the first time that popular music, a mass cultural form, had become a centrally significant medium for the dissemination of a range of sociopolitical issues, from US involvement in the Vietnam war to the Civil Rights Movements, to the rejection of western political and cultural ideology. As Eyerman and Jamison^([1])point out:‘Movement ideas, images,and feelings were disseminated in and through popular music and, at the same time, the movements of the times influenced developments, in both form and content, in popular music'.
基金the Beijing Outstanding Young Scientist Program of China(No.BJJWZYJH01201911413037)projects(Nos.41877257 and 51622404)supported by National Natural Science Foundation of China+1 种基金Shaanxi Coal Group Key Project of China(No.2018SMHKJ-A-J-03)the Fundamental Research Funds for the Central Universities of China(No.2021YJSLJ23)。
文摘Dynamic disasters,such as rock burst due to the breaking of large area stiff roof strata,are known to occur in the hard rock strata of coal mines.In this paper,mechanical models of the fracturing processes of thick hard rock strata were established based on the thick plate theory and numerical simulations.The results demonstrated that,based on the fracture characteristics of the thick hard rock strata,four fracture models could be analyzed in detail,and the corresponding theoretical failure criteria were determined in detail.In addition,the influence of weak interlayer position on the fracture models and ground pressure of rock strata is deeply analyzed,and six numerical simulation schemes have been implemented.The results showed that the working face pressure caused by the independent movement of the lower layer is relatively low.The different fracture type of the thick hard rock strata had different demands on the working resistance of the hydraulic powered supports.The working resistance of the hydraulic powered supports required by the stratified movements was lower than that of the non-stratified movements.
基金supported by the National Natural Science Foundation of China (41472272, 41225011)the Youth Science and Technology Fund of Sichuan Province (2016JQ0011)the Opening Fund of the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection (Chengdu University of Technology) (SKLGP2013K015)
文摘Mountain hazards with large masses of rock blocks in motion – such as rock falls, avalanches and landslides – threaten human lives and structures. Dynamic fragmentation is a common phenomenon during the movement process of rock blocks in rock avalanche, due to the high velocity and impacts against obstructions. In view of the energy consumption theory for brittle rock fragmentation proposed by Bond, which relates energy to size reduction, a theoretical model is proposed to estimate the average fragment size for a moving rock block when it impacts against an obstruction. Then, different forms of motion are studied, with various drop heights and slope angles for the moving rock block. The calculated results reveal that the average fragment size decreases as the drop height increases, whether for free-fall or for a sliding or rolling rock block, and the decline in size is rapid for low heights and slow for increasing heights in the corresponding curves. Moreover, the average fragment size also decreases as the slope angle increases for a slidingrock block. In addition, a rolling rock block has a higher degree of fragmentation than a sliding rock block, even for the same slope angle and block volume. Finally, to compare with others' results, the approximate number of fragments is estimated for each calculated example, and the results show that the proposed model is applicable to a relatively isotropic moving rock block.
基金supported by the NationalNatural Science Foundation of China(41402254)Department of Science and Technology of Shaanxi Province(2019ZDLSF07-0701)。
文摘Two branches of Tangjiagou rock avalanche were triggered by Lushan earthquake in Sichuan Province,China on April 20th,2013.The rock avalanche has transported about 1500000 m3 of sandstone from the source area.Based on discrete element modeling,this study simulates the deformation,failure and movement process of the rock avalanche.Under seismic loading,the mechanism and process of deformation,failure,and runout of the two branches are similar.In detail,the stress concentration occur firstly on the top of the mountain ridge,and accordingly,the tensile deformation appears.With the increase of seismic loading,the strain concentration zone extends in the forward and backward directions along the slipping surface,forming a locking segment.As a result,the slipping surface penetrates and the slide mass begin to slide down with high speed.Finally,the avalanche accumulates in the downstream and forms a small barrier lake.Modeling shows that a number of rocks on the surface exhibit patterns of horizontal throwing and vertical jumping under strong ground shaking.We suggest that the movement of the rock avalanche is a complicated process with multiple stages,including formation of the two branches,high-speed sliding,transformation into debris flows,further movement and collision,accumulation,and the final steady state.Topographic amplification effects are also revealed based on acceleration and velocity of special monitoring points.The horizontal and vertical runout distances of the surface materials are much greater than those of the internal materials.Besides,the sliding duration is also longer than that of the internal rock mass.
基金Supported by the National Major Science and Technology Project(2016ZX05007004)PetroChina Southwest Oil&Gas Field Branch Company Science and Technology Project(2019ZD01)。
文摘Based on outcrop, drilling, logging, geochemical analysis and seismic data, the karst landform and distribution of Permian volcanic rocks at the end of the sedimentary period of the Maokou Formation in the western Sichuan Basin are examined, and their petroleum geological significance is discussed. Affected by normal faults formed in the early magmatic activities and extension tectonic background in the late sedimentary period of the Maokou Formation, a local karst shallow depression under the background of karst slope came up in the Jianyang area of the western Sichuan Basin, where the residual thickness of the Maokou Formation was thinner. Basic volcanic rocks like pyroclastic rock of eruptive facies, basalt of overflow facies, diabase porphyrite of intrusive facies and sedimentary tuff of volcanic sedimentary facies were formed after karstification. However, under the effects of faulting and karst paleogeomorphology, the volcanic rocks in different areas had different accumulation features. In the Jianyang area, with long eruption time, the volcanic rocks were thick and complex in lithology, and accumulated in the karst depressions. In the Zhongjiang-Santai area located in the karst slope, there’s no fault developed, only thin layers of basalt and sedimentary tuff turned up. The karst landform controls the build-up of thick explosive facies volcanic rocks and also the development of karst reservoirs in the Maokou Formation, and the western Sichuan area has oil and gas exploration potential in volcanic rocks and the Maokou Formation.
基金the University of Azad Jammu and Kashmir Muzaffarabad,for funding the research under Faculty Development Programme
文摘The SPOT image analysis in Muzaffarabad Azad Kashmir,northwest Himalayas,Pakistan reveals that the Kashmir earthquake 2005 triggered a number of coseismic mass movements along the hanging wall block of the Muzaffarabad Fault.The Neelidandi and Langarpura rock falls have been identified as two major reactivated mass movements with an estimated volume of 3.1 × 106m3and 5.76 × 106m3,respectively.The Neelidandi and Langarpura mass movements were initiated during earthquake in the direction of northwest-southeast extension and northeastsouthwest directed thrusting,respectively.The Neelidandi rock fall occurred in sheared cherty dolomites and limestones of the Cambrian Muzaffarabad Formation,whereas the Langarpura rock fall occurred in alternating clays,shales,claystones,siltstones and sandstones of the Miocene Murree Formation.These rock units along the fault are highly fractured and jointed.The geotechnical maps and geological longitudinal profiles show the relationship between the geometrical characteristics and mechanism of these mass movements.Their characteristics were analyzed according to the role of topographic,seismic,geological and tectonic factors.The steep topography,sheared rocks,lithology,coseismic uplift and strong ground shaking of the hanging wall block along Muzaffarabad Fault facilitated the gravity collapse of these mass movements.
