Rockbursts, which mainly affect mining roadways, are dynamic disasters arising from the surrounding rock under high stress. Understanding the interaction between supports and the surrounding rock is necessary for effe...Rockbursts, which mainly affect mining roadways, are dynamic disasters arising from the surrounding rock under high stress. Understanding the interaction between supports and the surrounding rock is necessary for effective rockburst control. In this study, the squeezing behavior of the surrounding rock is analyzed in rockburst roadways, and a mechanical model of rockbursts is established considering the dynamic support stress, thus deriving formulas and providing characteristic curves for describing the interaction between the support and surrounding rock. Design principles and parameters of supports for rockburst control are proposed. The results show that only when the geostress magnitude exceeds a critical value can it drive the formation of rockburst conditions. The main factors influencing the convergence response and rockburst occurrence around roadways are geostress, rock brittleness, uniaxial compressive strength, and roadway excavation size. Roadway support devices can play a role in controlling rockburst by suppressing the squeezing evolution of the surrounding rock towards instability points of rockburst. Further, the higher the strength and the longer the impact stroke of support devices with constant resistance, the more easily multiple balance points can be formed with the surrounding rock to control rockburst occurrence. Supports with long impact stroke allow adaptation to varying geostress levels around the roadway, aiding in rockburst control. The results offer a quantitative method for designing support systems for rockburst-prone roadways. The design criterion of supports is determined by the intersection between the convergence curve of the surrounding rock and the squeezing deformation curve of the support devices.展开更多
A new rockburst classification, innovative works in developing a ‘‘strainburst test machine" and an‘‘impact-induced rockburst test machine" that can reproduce rockbursts in laboratory were researched.New...A new rockburst classification, innovative works in developing a ‘‘strainburst test machine" and an‘‘impact-induced rockburst test machine" that can reproduce rockbursts in laboratory were researched.New concepts were proposed regarding the stress paths that take into account both the static and dynamic stresses analogous to that at excavation boundaries for generating artificially-induced strainburst and impact-induced rockburst. As an important method for rockburst control, a novel energyabsorbing bolt was developed, which has a constant-resistance under both static and impact loadings and a large-elongation capacity for containing large deformations of rock masses under burst-prone conditions.展开更多
Rockburst problems induced by high in-situ stresses were prominent during construction of the headrace tunnels of Jinping II hydropower station. The rockbursts occurred in various forms, and it is necessary to take pe...Rockburst problems induced by high in-situ stresses were prominent during construction of the headrace tunnels of Jinping II hydropower station. The rockbursts occurred in various forms, and it is necessary to take pertinent measures for integrated prevention and control of rockbursts. In view of the rockburst characteristics during tunnel construction of Jinping II hydropower station, the engineering geological conditions were presented, and the features, mechanisms and forms of rockbursts observed during construction were analyzed in detail. A large number of scientific researches, experiments and applications were conducted. Multiple measures were adopted to prevent and control rockbursts, including the prediction and early warning measures, stress relief by blasting in advance, optimized blasting design and optimized tunnel support in the tunnel sections prone to strong rockbursts. The effectiveness of these prevention and control measures was evaluated. Experiences have been accumulated through a great number of helpful explorations and practices for rockburst prevention and control. A comprehensive rockburst prevention and control system has been gradually established.展开更多
The studies of prediction and control of rockburst are presented during deep excavation in a gold mine in China. Firstly,the stress-relief method is used to obtain a vast amount of data about initial geostress. Second...The studies of prediction and control of rockburst are presented during deep excavation in a gold mine in China. Firstly,the stress-relief method is used to obtain a vast amount of data about initial geostress. Secondly,3D FEM analyses of large scale are performed to find out the law of geostress distribution at various excavation levels of the mining area. At the same time,as an equally important measure,six typical kinds of rock blocks are sampled for the experimental study of rockburst tendency. According to the synthesized results of the theoretical and testing results,the methods of brittleness coefficient,brittle index and stress,and so on,are adopted. Finally,the evaluation on the possibility of rockbursts is given that may take place at the deep mining area and some effective measures are put forward to prevent and control the rockburst.展开更多
In order to resolve how to mine under the condition of high stress with rockburst, this paper analyzes the law of rockburst, and considers that most of the rockbursts occur in the high stress area of stope. A method o...In order to resolve how to mine under the condition of high stress with rockburst, this paper analyzes the law of rockburst, and considers that most of the rockbursts occur in the high stress area of stope. A method of rockburst forecast and its steps are given, and three different stages of rockburst are identified. Furthermore, this paper considers that blasting energy can effectively control rockburst by changing the characteristics of rock mass, which decreases the probability of rockburst happening. According to characteristics of rockburst, two feasible mining techniques under rockburst conditions are put forward, that is stoping and filling method, and sublevel caving method of mining without any sills in hanging wall.展开更多
In recent years,the mining depth of steeply inclined coal seams in the Urumqi mining area has gradually increased.Local deformation of mining coal-rock results in frequent rockbursts.This has become a critical issue t...In recent years,the mining depth of steeply inclined coal seams in the Urumqi mining area has gradually increased.Local deformation of mining coal-rock results in frequent rockbursts.This has become a critical issue that affects the safe mining of deep,steeply inclined coal seams.In this work,we adopt a perspective centered on localized deformation in coal-rock mining and systematically combine theoretical analyses and extensive data mining of voluminous microseismic data.We describe a mechanical model for the urgently inclined mining of both the sandwiched rock pillar and the roof,explaining the mechanical response behavior of key disaster-prone zones within the deep working face,affected by the dynamics of deep mining.By exploring the spatial correlation inherent in extensive microseismic data,we delineate the“time-space”response relationship that governs the dynamic failure of coal-rock during the progression of the sharply inclined working face.The results disclose that(1)the distinctive coal-rock occurrence structure characterized by a“sandwiched rock pillar-B6 roof”constitutes the origin of rockburst in the southern mining area of the Wudong Coal Mine,with both elements presenting different degrees of deformation localization with increasing mining depth.(2)As mining depth increases,the bending deformation and energy accumulation within the rock pillar and roof show nonlinear acceleration.The localized deformation of deep,steeply inclined coal-rock engenders the spatial superposition of squeezing and prying effects in both the strike and dip directions,increasing the energy distribution disparity and stress asymmetry of the“sandwiched rock pillar-B3+6 coal seam-B6 roof”configuration.This makes worse the propensity for frequent dynamic disasters in the working face.(3)The developed high-energy distortion zone“inner-outer”control technology effectively reduces high stress concentration and energy distortion in the surrounding rock.After implementation,the average apparent resistivity in the rock pillar and B6 roof substantially increased by 430%and 300%,respectively,thus guaranteeing the safe and efficient development of steeply inclined coal seams.展开更多
基金funded by the National Natural Science Foundation of China (No. 52304133)the National Key R&D Program of China (No. 2022YFC3004605)the Department of Science and Technology of Liaoning Province (No. 2023-BS-083)。
文摘Rockbursts, which mainly affect mining roadways, are dynamic disasters arising from the surrounding rock under high stress. Understanding the interaction between supports and the surrounding rock is necessary for effective rockburst control. In this study, the squeezing behavior of the surrounding rock is analyzed in rockburst roadways, and a mechanical model of rockbursts is established considering the dynamic support stress, thus deriving formulas and providing characteristic curves for describing the interaction between the support and surrounding rock. Design principles and parameters of supports for rockburst control are proposed. The results show that only when the geostress magnitude exceeds a critical value can it drive the formation of rockburst conditions. The main factors influencing the convergence response and rockburst occurrence around roadways are geostress, rock brittleness, uniaxial compressive strength, and roadway excavation size. Roadway support devices can play a role in controlling rockburst by suppressing the squeezing evolution of the surrounding rock towards instability points of rockburst. Further, the higher the strength and the longer the impact stroke of support devices with constant resistance, the more easily multiple balance points can be formed with the surrounding rock to control rockburst occurrence. Supports with long impact stroke allow adaptation to varying geostress levels around the roadway, aiding in rockburst control. The results offer a quantitative method for designing support systems for rockburst-prone roadways. The design criterion of supports is determined by the intersection between the convergence curve of the surrounding rock and the squeezing deformation curve of the support devices.
基金Financial support from the National Key Research and Development Program (No.2016YFC0600901)the National Natural Science Foundation of China (No.51704298)
文摘A new rockburst classification, innovative works in developing a ‘‘strainburst test machine" and an‘‘impact-induced rockburst test machine" that can reproduce rockbursts in laboratory were researched.New concepts were proposed regarding the stress paths that take into account both the static and dynamic stresses analogous to that at excavation boundaries for generating artificially-induced strainburst and impact-induced rockburst. As an important method for rockburst control, a novel energyabsorbing bolt was developed, which has a constant-resistance under both static and impact loadings and a large-elongation capacity for containing large deformations of rock masses under burst-prone conditions.
文摘Rockburst problems induced by high in-situ stresses were prominent during construction of the headrace tunnels of Jinping II hydropower station. The rockbursts occurred in various forms, and it is necessary to take pertinent measures for integrated prevention and control of rockbursts. In view of the rockburst characteristics during tunnel construction of Jinping II hydropower station, the engineering geological conditions were presented, and the features, mechanisms and forms of rockbursts observed during construction were analyzed in detail. A large number of scientific researches, experiments and applications were conducted. Multiple measures were adopted to prevent and control rockbursts, including the prediction and early warning measures, stress relief by blasting in advance, optimized blasting design and optimized tunnel support in the tunnel sections prone to strong rockbursts. The effectiveness of these prevention and control measures was evaluated. Experiences have been accumulated through a great number of helpful explorations and practices for rockburst prevention and control. A comprehensive rockburst prevention and control system has been gradually established.
基金Natural Science Foundation of China under Grant No.59979026.
文摘The studies of prediction and control of rockburst are presented during deep excavation in a gold mine in China. Firstly,the stress-relief method is used to obtain a vast amount of data about initial geostress. Secondly,3D FEM analyses of large scale are performed to find out the law of geostress distribution at various excavation levels of the mining area. At the same time,as an equally important measure,six typical kinds of rock blocks are sampled for the experimental study of rockburst tendency. According to the synthesized results of the theoretical and testing results,the methods of brittleness coefficient,brittle index and stress,and so on,are adopted. Finally,the evaluation on the possibility of rockbursts is given that may take place at the deep mining area and some effective measures are put forward to prevent and control the rockburst.
基金TheNationalNatureScienceFoundationofChina (No .5 0 0 74 0 34) TheTeachingandResearchAwardProgramforOutstandingYoungProfessorsinHigherEducationInstitute.
文摘In order to resolve how to mine under the condition of high stress with rockburst, this paper analyzes the law of rockburst, and considers that most of the rockbursts occur in the high stress area of stope. A method of rockburst forecast and its steps are given, and three different stages of rockburst are identified. Furthermore, this paper considers that blasting energy can effectively control rockburst by changing the characteristics of rock mass, which decreases the probability of rockburst happening. According to characteristics of rockburst, two feasible mining techniques under rockburst conditions are put forward, that is stoping and filling method, and sublevel caving method of mining without any sills in hanging wall.
基金financially supported by the Major Program of the National Natural Science Foundation of China(No.52394191)the Outstanding Ph.D Dissertation Cultivating Program of Xi’an University of Science and Technology(No.PY22001)the National Foundation for studying abroad(No.[2022]87)。
文摘In recent years,the mining depth of steeply inclined coal seams in the Urumqi mining area has gradually increased.Local deformation of mining coal-rock results in frequent rockbursts.This has become a critical issue that affects the safe mining of deep,steeply inclined coal seams.In this work,we adopt a perspective centered on localized deformation in coal-rock mining and systematically combine theoretical analyses and extensive data mining of voluminous microseismic data.We describe a mechanical model for the urgently inclined mining of both the sandwiched rock pillar and the roof,explaining the mechanical response behavior of key disaster-prone zones within the deep working face,affected by the dynamics of deep mining.By exploring the spatial correlation inherent in extensive microseismic data,we delineate the“time-space”response relationship that governs the dynamic failure of coal-rock during the progression of the sharply inclined working face.The results disclose that(1)the distinctive coal-rock occurrence structure characterized by a“sandwiched rock pillar-B6 roof”constitutes the origin of rockburst in the southern mining area of the Wudong Coal Mine,with both elements presenting different degrees of deformation localization with increasing mining depth.(2)As mining depth increases,the bending deformation and energy accumulation within the rock pillar and roof show nonlinear acceleration.The localized deformation of deep,steeply inclined coal-rock engenders the spatial superposition of squeezing and prying effects in both the strike and dip directions,increasing the energy distribution disparity and stress asymmetry of the“sandwiched rock pillar-B3+6 coal seam-B6 roof”configuration.This makes worse the propensity for frequent dynamic disasters in the working face.(3)The developed high-energy distortion zone“inner-outer”control technology effectively reduces high stress concentration and energy distortion in the surrounding rock.After implementation,the average apparent resistivity in the rock pillar and B6 roof substantially increased by 430%and 300%,respectively,thus guaranteeing the safe and efficient development of steeply inclined coal seams.
