As mining and civil tunneling progresses to depth, excavation-induced seismicity and rockburst problems increase and cannot be prevented. As an important line of defense, ground control measures and burst-resistant ro...As mining and civil tunneling progresses to depth, excavation-induced seismicity and rockburst problems increase and cannot be prevented. As an important line of defense, ground control measures and burst-resistant rock support are used to prevent or minimize damage to excavations and thus to enhance workplace safety. Rock support in burst-prone ground differs from conventional rock support where controlling gravity-induced rockfalls and managing shallow zones of loose rock are the main target. Rock support in burst-prone ground needs to resist dynamic loads and large rock dilation due to violent rock failure. After reviewing the rockburst phenomenon, types of rockbursts, damage mechanisms, and rockburst support design principles and acceptability criteria, this paper describes that the support selection process in burst-prone ground is iterative, requiring design verification and modification based on field observations. An interactive design tool for conducting rockburst support design in underground tunnels is introduced to facilitate cost-effective design.展开更多
There are considerable challenges associated with the design of ground support for seismically-active underground mines.It is extremely difficult to establish the demand on ground support as well as the capacity of a ...There are considerable challenges associated with the design of ground support for seismically-active underground mines.It is extremely difficult to establish the demand on ground support as well as the capacity of a ground support system.The resulting dynamic or impact loads caused by mining-induced seismicity are difficult to anticipate and quantify.The performance of a ground support system is defined by the load distribution and interaction between several reinforcement and surface support elements.Consequently,the design of ground support in seismically-active mines tends to evolve,or be modified based on qualitative assessments of perceived performance or response to significant seismic events or rockbursts.This research is motivated by a need to provide quantitative and data-driven design guidelines for ground support systems subjected to dynamic-loading conditions.Rockburst data were collected from three deep and seismically-active underground mines in the Sudbury basin in Canada.The constructed database comprises 209 seismic events that resulted in damage to mine excavations and ground support.These events were associated with damage at 324 locations within the three mines.The developed ground support design strategy,based on these documented case studies,identifies areas where the use of dynamic or enhanced support should be employed.The developed design methodology provides guidelines for the zoning of mine locations in which installation of enhanced support is recommended,the specifications for an optimal ground support system,and the timing or sequence of installation.展开更多
Rockbursts occur as a direct consequence of underground mining or civil excavation.The general scale of their seismic disturbance and consequences depend upon known factors.However,uncertainty remains as to exactly wh...Rockbursts occur as a direct consequence of underground mining or civil excavation.The general scale of their seismic disturbance and consequences depend upon known factors.However,uncertainty remains as to exactly when and where rockbursts will occur,as well as the effectiveness of ground support measures to fully mitigate their consequences.While the uncertainty in when and where is a dilemma shared with earthquake prediction,that associated with ground support capability is both a design and a management concern.Following a brief review of the known mechanisms that produce rockbursts,the paper explores the sources and scales of energy demands that characterize the risk of their damaging consequences upon underground excavations.We note that some of this risk continues to be associated with uncertainty with respect to rockmass properties and in situ stress,particularly in the context of deep mining.A review is presented of all available yielding ground support systems and their necessary design requirements,identifying practical weaknesses and limitations where these are known.The paper concludes with some suggested areas where further study and development could provide the ways and means to reduce the design uncertainty in managing rockbursts.展开更多
文摘As mining and civil tunneling progresses to depth, excavation-induced seismicity and rockburst problems increase and cannot be prevented. As an important line of defense, ground control measures and burst-resistant rock support are used to prevent or minimize damage to excavations and thus to enhance workplace safety. Rock support in burst-prone ground differs from conventional rock support where controlling gravity-induced rockfalls and managing shallow zones of loose rock are the main target. Rock support in burst-prone ground needs to resist dynamic loads and large rock dilation due to violent rock failure. After reviewing the rockburst phenomenon, types of rockbursts, damage mechanisms, and rockburst support design principles and acceptability criteria, this paper describes that the support selection process in burst-prone ground is iterative, requiring design verification and modification based on field observations. An interactive design tool for conducting rockburst support design in underground tunnels is introduced to facilitate cost-effective design.
文摘There are considerable challenges associated with the design of ground support for seismically-active underground mines.It is extremely difficult to establish the demand on ground support as well as the capacity of a ground support system.The resulting dynamic or impact loads caused by mining-induced seismicity are difficult to anticipate and quantify.The performance of a ground support system is defined by the load distribution and interaction between several reinforcement and surface support elements.Consequently,the design of ground support in seismically-active mines tends to evolve,or be modified based on qualitative assessments of perceived performance or response to significant seismic events or rockbursts.This research is motivated by a need to provide quantitative and data-driven design guidelines for ground support systems subjected to dynamic-loading conditions.Rockburst data were collected from three deep and seismically-active underground mines in the Sudbury basin in Canada.The constructed database comprises 209 seismic events that resulted in damage to mine excavations and ground support.These events were associated with damage at 324 locations within the three mines.The developed ground support design strategy,based on these documented case studies,identifies areas where the use of dynamic or enhanced support should be employed.The developed design methodology provides guidelines for the zoning of mine locations in which installation of enhanced support is recommended,the specifications for an optimal ground support system,and the timing or sequence of installation.
文摘Rockbursts occur as a direct consequence of underground mining or civil excavation.The general scale of their seismic disturbance and consequences depend upon known factors.However,uncertainty remains as to exactly when and where rockbursts will occur,as well as the effectiveness of ground support measures to fully mitigate their consequences.While the uncertainty in when and where is a dilemma shared with earthquake prediction,that associated with ground support capability is both a design and a management concern.Following a brief review of the known mechanisms that produce rockbursts,the paper explores the sources and scales of energy demands that characterize the risk of their damaging consequences upon underground excavations.We note that some of this risk continues to be associated with uncertainty with respect to rockmass properties and in situ stress,particularly in the context of deep mining.A review is presented of all available yielding ground support systems and their necessary design requirements,identifying practical weaknesses and limitations where these are known.The paper concludes with some suggested areas where further study and development could provide the ways and means to reduce the design uncertainty in managing rockbursts.
