## 2 Literature Review
### Blasting  
The blasting technique utilises an explosive device situated in a borehole near the mine to simulate dynamic loading from seismic activities [12; 13]. In contrast to the drop test, this technique considers in-situ rockmass conditions as it is conducted on site [4; 7; 8]. This was one of the major limitations of drop testing. The blasting experiment involves drilling adjacent bore holes in the walls of the tunnel, filling them with explosives and remotely detonating the load. A high-speed camera is set up inside the excavation to capture the deformation and behaviour of the reinforcement. Mapping of the test site before and after each blast enables a comparison of blasting effects to be monitored. [PERSON], [PERSON] and [PERSON] [14] utilised Sirovision, a 3D photogrammetry system developed by the CSIRO to map the conditions of the test site. However, it was found that limitations of using this \begin{table}
\begin{tabular}{l l} \hline \hline
**Advantages** & **Disadvantages** \\ \hline Simple and quick to perform & Impact loading may not be representative of rockburst loading \\ Repeatable results & When impact via a load spreader is used, the true load impacted to the support is unknown \\ Suitable for comparative testing and quality & Appropriate representation of lateral \\ control testing & continuity of support is unlikely to be achieved \\  & The effect of the stress in, or confinement or, the rock mass is usually not considered \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Advantages and disadvantages of drop testing. video-based analysis included potential inaccurate surveying due to movement of control points after blasting which can cause errors in measurement of angles and distances on the digital images. In the [PERSON] et al. [14], assessment of in-situ performance of ground support systems subjected to dynamic loading, blasting was the primary technique chosen. Their goal was to investigate rockmass discontinuities, rockmass damage, stress conditions on rockburst damage and the influence of support and reinforcement systems. A diagram of their set up can be seen below in Figure 1.  
To measure the progressive influence of an increased dynamic load on the wall, each blasthole was separately charged and detonated. A benefit of testing at several borehole locations is that it allows the obtainment of data on various locations of the same excavation. [PERSON] and [PERSON] [12] stated that there are 6 elements of control, charge-length, borehole diameter, velocity of detonation, pressure function, rise-time, and peak pressure. Additionally, [PERSON] et al. [14] highlighted that another fundamental flaw was the utilisation of gas-powered explosives, such as ANFO as they generate rapidly expanding blast gasses. This could potentially compromise the validity of the results. Emulsion products are favourable, however, due to limitation of products available on site and in the respective country and market, this cannot always be used [14]. [PERSON] et al. [15] conducted a similar test, utilising MINSIM modelling as opposed to Sirovision. Both tests followed the same methodologies. [PERSON] et al. had concluded that due to their 5 m blast hole from the tunnel wall, the impacts of rapidly expanding gas effects would be minimised. These tests could have been improved by utilising an emulsion-based explosive which would eliminate these effects. Interestingly, [PERSON] et al. [15] found that the peak particle velocity (PPV) ranged from 0.7 m/s to 2.5 m/s in low intensity areas whilst high intensity areas experienced speeds up to 3.3 m/s. However, [PERSON] [8] findings described an average PPV of 10 m/s and in some extreme cases up to 50 m/s. Because dynamic loading capacity is related to ejection velocity of rock particles [7; 16], [PERSON] et al. [15] could have improved their tests by increasing the charge load to induce rock ejection velocities similar to that documented by [PERSON] (2012).