Ground support is widely implemented to mitigate dynamic rock failures in underground mines.This paper investigated the ground support requirements in burst-prone mines to mitigate the catastrophic dynamic rock failur...Ground support is widely implemented to mitigate dynamic rock failures in underground mines.This paper investigated the ground support requirements in burst-prone mines to mitigate the catastrophic dynamic rock failures of rock and/or coal bursts.First,the ground support principles and considerations in burst-prone conditions are identified.The objective of a ground support system is to increase the capacity to accommodate rock fracturing in a rockburst and,in turn,to minimize the kinetic energy of the ejected material.The support capacities of various yielding rockbolts and integrated support systems are then investigated using the test results in the laboratory.Apart from the energy absorption and yielding deformation capacity,the initial stiffness and energy absorption rate are also critical factors when applying yielding rockbolts in practice.Adding rope lacing and mesh strap to surface support elements can substantially enhance the support performance of the system.In practice,semi-analytical and empirical approaches are often used to determine the ground support elements in burst-prone areas.Semi-analytical methods first evaluate the support demand in burst risk zones and then select support elements according to their laboratory test results.Alternatively,empirical methods determine the ground support elements according to the locally established empirical rating scheme,which usually ranks the support capacities of various support systems based on ground support conditions and damage conditions.The outcomes of this study can provide insights into ground support strategies and assist the mining industry to develop effective coal burst control technologies.展开更多
To better understand the failure behaviours and strength of bolt-reinforced blocky rocks,large scale extensive laboratory experiments are carried out on blocky rock-like specimens with and without rockbolt reinforceme...To better understand the failure behaviours and strength of bolt-reinforced blocky rocks,large scale extensive laboratory experiments are carried out on blocky rock-like specimens with and without rockbolt reinforcement.The results show that both shear failure and tensile failure along joint surfaces are observed but the shear failure is a main controlling factor for the peak strength of the rock mass with and without rockbolts.The rockbolts are necked and shear deformation simultaneously happens in bolt reinforced rock specimens.As the joint dip angle increases,the joint shear failure becomes more dominant.The number of rockbolts has a significant impact on the peak strain and uniaxial compressive strength(UCS),but little influence on the deformation modulus of the rock mass.Using the Winkler beam model to represent the rockbolt behaviours,an analytical model for the prediction of the strength of boltreinforced blocky rocks is proposed.Good agreement between the UCS values predicted by proposed model and obtained from experiments suggest an encouraging performance of the proposed model.In addition,the performance of the proposed model is further assessed using published results in the literature,indicating the proposed model can be used effectively in the prediction of UCS of bolt-reinforced blocky rocks.展开更多
Despite recent advances in mine health and safety, roof collapse and instabilities are still the leading causes of injury and fatality in underground mining operations. Improving safety and optimum design of ground su...Despite recent advances in mine health and safety, roof collapse and instabilities are still the leading causes of injury and fatality in underground mining operations. Improving safety and optimum design of ground support requires good and reliable ground characterization. While many geophysical methods have been developed for ground characterizations, their accuracy is insufficient for customized ground support design of underground workings. The actual measurements on the samples of the roof and wall strata from the exploration boring are reliable but the related holes are far apart, thus unsuitable for design purposes. The best source of information could be the geological back mapping of the roof and walls, but this is disruptive to mining operations, and provided information is only from rock surface.Interpretation of the data obtained from roof bolt drilling can offer a good and reliable source of information that can be used for ground characterization and ground support design and evaluations. This paper offers a brief review of the mine roof characterization methods, followed by introduction and discussion of the roof characterization methods by instrumented roof bolters. A brief overview of the results of the preliminary study and initial testing on an instrumented drill and summary of the suggested improvements are also discussed.展开更多
In order to realize the real-time and precise test for a weapon system of a certain type of fighter,a signal classification method according to attributes is proposed,common input channels for multiple signals are con...In order to realize the real-time and precise test for a weapon system of a certain type of fighter,a signal classification method according to attributes is proposed,common input channels for multiple signals are configured optimally,and a test adapter and an adaptive signal conditioning module is designed. The hardware of conditioning module can be configured flexibly and the programmable test range can be adjusted owing to programmable multiplexer. An FPGA adaptive filter is designed by the calculated filter coefficient vectors with LMS method to solve the problem of parallel test of fighter weapon system in electromagnetic interference environment. The adaptive signal conditioning technology is characterized by high efficiency,precision and integration. Its application makes the test system successful to conduct real-time and parallel test for a weapon system,which is developed based on VXI bus and virtual-instrument technology.展开更多
文摘Ground support is widely implemented to mitigate dynamic rock failures in underground mines.This paper investigated the ground support requirements in burst-prone mines to mitigate the catastrophic dynamic rock failures of rock and/or coal bursts.First,the ground support principles and considerations in burst-prone conditions are identified.The objective of a ground support system is to increase the capacity to accommodate rock fracturing in a rockburst and,in turn,to minimize the kinetic energy of the ejected material.The support capacities of various yielding rockbolts and integrated support systems are then investigated using the test results in the laboratory.Apart from the energy absorption and yielding deformation capacity,the initial stiffness and energy absorption rate are also critical factors when applying yielding rockbolts in practice.Adding rope lacing and mesh strap to surface support elements can substantially enhance the support performance of the system.In practice,semi-analytical and empirical approaches are often used to determine the ground support elements in burst-prone areas.Semi-analytical methods first evaluate the support demand in burst risk zones and then select support elements according to their laboratory test results.Alternatively,empirical methods determine the ground support elements according to the locally established empirical rating scheme,which usually ranks the support capacities of various support systems based on ground support conditions and damage conditions.The outcomes of this study can provide insights into ground support strategies and assist the mining industry to develop effective coal burst control technologies.
基金supported by the National Key Research and Development Projects of China(No.2021YFB2600402)National Natural Science Foundation of China(Nos.52209148 and 52374119)+1 种基金the opening fund of State Key Laboratory of Geomechanics and Geotechnical Engineering,Institute of Rock and Soil Mechanics,Chinese Academy of Sciences(No.SKLGME023023)the opening fund of Key Laboratory of Water Management and Water Security for Yellow River Basin,Ministry of Water Resources(No.2023-SYSJJ-02)。
文摘To better understand the failure behaviours and strength of bolt-reinforced blocky rocks,large scale extensive laboratory experiments are carried out on blocky rock-like specimens with and without rockbolt reinforcement.The results show that both shear failure and tensile failure along joint surfaces are observed but the shear failure is a main controlling factor for the peak strength of the rock mass with and without rockbolts.The rockbolts are necked and shear deformation simultaneously happens in bolt reinforced rock specimens.As the joint dip angle increases,the joint shear failure becomes more dominant.The number of rockbolts has a significant impact on the peak strain and uniaxial compressive strength(UCS),but little influence on the deformation modulus of the rock mass.Using the Winkler beam model to represent the rockbolt behaviours,an analytical model for the prediction of the strength of boltreinforced blocky rocks is proposed.Good agreement between the UCS values predicted by proposed model and obtained from experiments suggest an encouraging performance of the proposed model.In addition,the performance of the proposed model is further assessed using published results in the literature,indicating the proposed model can be used effectively in the prediction of UCS of bolt-reinforced blocky rocks.
基金supported by the funding of the National Institute for Occupational Safety and Health under a contract with the Pennsylvania State University as part of the capacity building in ground supportthe funding from TüBITAK of Turkey has been used to support the sabbatical leave of Dr.Kahraman who made some contributions to this study
文摘Despite recent advances in mine health and safety, roof collapse and instabilities are still the leading causes of injury and fatality in underground mining operations. Improving safety and optimum design of ground support requires good and reliable ground characterization. While many geophysical methods have been developed for ground characterizations, their accuracy is insufficient for customized ground support design of underground workings. The actual measurements on the samples of the roof and wall strata from the exploration boring are reliable but the related holes are far apart, thus unsuitable for design purposes. The best source of information could be the geological back mapping of the roof and walls, but this is disruptive to mining operations, and provided information is only from rock surface.Interpretation of the data obtained from roof bolt drilling can offer a good and reliable source of information that can be used for ground characterization and ground support design and evaluations. This paper offers a brief review of the mine roof characterization methods, followed by introduction and discussion of the roof characterization methods by instrumented roof bolters. A brief overview of the results of the preliminary study and initial testing on an instrumented drill and summary of the suggested improvements are also discussed.
基金Sponsored by the Key Equipment Research Project of Air Force of China (KJZ06119)
文摘In order to realize the real-time and precise test for a weapon system of a certain type of fighter,a signal classification method according to attributes is proposed,common input channels for multiple signals are configured optimally,and a test adapter and an adaptive signal conditioning module is designed. The hardware of conditioning module can be configured flexibly and the programmable test range can be adjusted owing to programmable multiplexer. An FPGA adaptive filter is designed by the calculated filter coefficient vectors with LMS method to solve the problem of parallel test of fighter weapon system in electromagnetic interference environment. The adaptive signal conditioning technology is characterized by high efficiency,precision and integration. Its application makes the test system successful to conduct real-time and parallel test for a weapon system,which is developed based on VXI bus and virtual-instrument technology.
