State-of-art of testing and performance evaluation of rock bolt supports in underground mining structures

Abstract

External supports form integral part of mining structures maintaining the integrity and prevention of fall of rock from roof or sides for designed life of a rock structures. Rock bolts are being popularly used in mines to stabilize the deforming rock mass providing an unobstructed opening for improved ventilation with lesser maintenance while offering increased production and productivity of mine workings. Different types of rock bolts perform differently in different strata conditions. Therefore, a suitable method for reliable assessment of integrity and load-deformation behaviour of the rock bolts is very important to ensure rational design and effective application in rock bolts in mining structures. This paper reviews various destructive and non-destructive methods developed for evaluation of bolt performance. The study suggests that none of these testing methods can be used individually to get complete information about performance of a rock bolt. It is advisable to adopt an integrated approach combining the benefits of destructive as well as non-destructive testing methods for this purpose. Non-destructive testing methods should be used to estimate installed length, grout quality and location and type of defects whereas destructive testing methods should be used to obtain anchorage strength and the load-deformation characteristics of the rock bolt system. This approach will provide complete information as required for reliable design and effective installation of the support system.