An integral component of any underground excavation design is the Rock Support elements that provide artificial reinforcement. These typically include, mechanical rock bolts, grouted rebar, cable bolts, friction stabilizers, and shotcrete. Unlike ground control management, where the problem is often poorly defined because the stress/strain curve of the rock mass is not well understood, the mechanical characteristics of rock support elements are well known. Hence, if it is assumed that a failed or ruptured support system will dramatically increase the risk of a Fall of Ground, then monitoring of Rock Support Elements is a definitive indicator of “health” of the excavation.
YieldPoint is currently developing a wide range of products which will provide data on the load carried by support systems. For example, the low cost LIFEBOLT load cell product provides a cost effective load cell that can be attached to any type of rock bolt and will indicate the load developed and hence the "residual capacity" of the bolt. The low cost of this product empowers the user to deploy the product routinely.
Based on the data obtained a Factor of Safety can be assessed and objective management decisions can be made with respect to problems such as:
Rock
support condition following Seismic events
Timing and
locations for rehabilitation of Rock Support Systems
Optimal
timing and location for the application of Shotcrete
Design
optimization and in particular the assessment of support stiffness
Performance of shotcrete pillars and the interaction between the pillar
and the roof it is designed to support
Monitoring data provides engineering staff and consultants with the “objective” information to enable informed decision-making, that will result in more effective solutions. Routine and methodical monitoring (as opposed to crisis deployment) can help avoid the occurrence of catastrophic situations, based directly on the data, and through the enhancement of understanding that is associated with the development of an objective database of Rock Support Performance.