Specialised Testing of Dynamic Ground Support Elements
Ground support testing plays an important role in ensuring that the performance and behaviour of ground support elements are well understood. This is especially important as ground support systems are the last geotechnical control engineers have in place to ensure the stability of underground excavations. The uncontrolled failure of excavations has a large knock-on effect on both the safety of mining personnel and the cost to mining operations due to the loss of both equipment and time.
Ground support design for quasi-static conditions are relatively well understood and testing these support units both in the lab and in-situ is relatively easy. Unfortunately, testing of dynamic ground support (for seismic conditions) is much more challenging and requires a specialised lab. Due to the large energies and short impact times (<2 milliseconds) being tested, these facilities must be able to handle large impact weights (>1 tonne) and have sensitive high-speed instrumentation installed. Setting up such labs used to be highly expensive and were mainly funded and driven by research facilities and universities. This, however, is not the case anymore, and several ground support companies and manufacturers have begun setting up such facilities. This has made testing times a lot shorter and more economical than it used to be a decade ago.
As more facilities are built with specific testing practices in mind, the number of different ground support parameters which can be tested has increased. Here are just some of the parameters which can be considered for dynamic impact testing:
Rock mass modulus
Bolt behaviour under a single drop to failure
Bolt behaviour under several drops
Corrosion
Bolt behaviour under a mixture of static and dynamic loading
Grout and resin performance
Bolt behaviour in broken ground
The effect of installation quality on bolts
Bolt behaviour under shearing
Split tube configurations
These analysis options make it possible for us, as geotechnical engineers, to investigate several “too hard” questions we face daily. These include questions about the performance of bolts after rock bursts, and the leading reasons for bolt failure. Comparison of different bolts with the aim to determine which bolts are better suited for mine specific needs. Investigation of unique bolt installation options eg. dynamic bolts installed inside grouted friction bolts.
These tests used to be extremely costly and lengthy, often taking several months to years to complete. Now, they can be more cost-effective and much less time-consuming.
Interested in learning more? Get in touch with us, and we can either arrange a visit to see these tests in action or schedule a live stream. Interested in getting bolts tested? We offer the following services:
Dynamic bolt testing with the following specifications:
Specified rock modulus
Bolt behaviour under a single drop to failure
Bolt behaviour under several drops
Grout and resin performance
The effect of installation quality on bolts
Comparative testing between two bolts
Contact us and we will provide you with a detailed quote.
Below a video of a typical test with the displacement versus load instrumentation measurements underneath.
