THE ISSUE

The Canadian Rockburst Support Handbook (Kaiser et al., 1996) presented an engineering approach to selecting rock support for burst‐prone mines by systematically assessing both support demands and support capacities. Since its publication, technology of rockburst support has seen many new developments. A number of key insights, changes in thinking, and new concepts have emerged over the last two decades. In some cases, the practical implications have been immediately apparent, whereas in other cases, the full implications are only now emerging with the development of new methods of analysis and new design approaches. Development of “The Canadian Rockburst Support Selection” is an update of the handbook. It addresses the fundamental principles, methodologies and procedures in rockburst support design, and will assist practicing engineers in following systematic design procedures.

THE SOLUTION

Intended for ground control engineers with a sound background in engineering design, rock mechanics, stress modeling, and static ground control principles, A Guide to Rockburst Support Selection (Cai & Kaiser, 2014), focuses on aspects that are most important for rock support in burst‐prone ground, particularly within the context of the current situation in hard rock mines and civil tunnels in Canada, Australia, Chile, South Africa, China, and many other countries. Extensive field and laboratory testing of support elements and systems under both static and dynamic conditions have generated key data for design, and have led to new insights concerning the mechanisms or behaviour by which rock support dynamically interacts with the ground. In addition to the conventional grouping of rockburst types into strainburst, pillar burst, fault-slip burst, a distinction between static‐load‐induced or dynamically triggered and dynamically loaded strainbursts is essential for the support demand estimation.

As well, identification of three distinct rockburst damage mechanisms involved in most of the damage caused by rockbursts in deep underground mines form the fundamental basis for the design approach presented in this Guide:

  • Sudden volume expansion or bulking of the rock due to fracturing of the rockmass around an excavation.
  • Rockfalls (or falls of ground), which have been triggered or loaded by seismic shaking.
  • Ejection of rock caused by: (1) momentum transfer from violently bulking (larger) blocks or slabs of rock to smaller blocks that are free to eject (e.g., between bolts), and (2) energy transfer from large remote seismic events to fractured rock near a stressed excavation

For each of these mechanisms, the Guide presents detailed methods of analysis for support design.
The guide treats support design as a two‐stage engineering process; determining the expected loading conditions or demand on support; and integrating the various elements into a support system to achieve a support capacity that exceeds demand.

INNOVATION IN PROGRESS

The Guide to Rockburst Support Selection is scheduled for publication in 2014. Workshops and short courses will be offered in support of the guide. In addition, a software tool (BurstSupport™) has been developed in tandem to assist in applying the design methodology to a computer aided design package that rapidly executes design calculations at all affected tunnel locations.

Contact

  • Ming Cai, MIRARCO, Laurentian University
  • 1-705-675-1151 x 5099
  • mcai@laurentian.ca
  • www.laurentian.ca

Solution team

  • Damien Duff, CEMI
  • Simon Nickson, Vale
  • Lars Malmgren, LKAB
  • Peter K. Kaiser, CEMI, RTC-UMC
  • Claire McAneney, NSERC