## 2 Literature Review
### Drop Testing  
Ground reinforcement and support systems have been a major engineering challenge that has threatened the mining industry due to a lack of adequate testing that has yielded reliable and valid results [4]. [PERSON] and [PERSON] [2] criticise the lack of further research that has been conducted to meet these design challenges and implores more rigorous testing methods to develop a more comprehensive understanding of dynamic loading induced by seismic activity. One of the common testing methods is the drop test. It involves directly dropping a large mass onto a reinforcement support element, such as a plate or cable bolt embedded into concrete. An analysis is conducted through a computerised measurement of the forces that are imparted as well as an assessment of the strain and deformations. [PERSON] et al. [5] utilised the drop test to measure the non-linear interaction between tensile and shear capacity of cable bolts subject to dynamic loading conditions. It was noted that a key limitation of the test is the consideration of energy loss transfers, such as dissipated losses and shaking of the loaded frame. Additionally, [PERSON] and [PERSON] [6] in their assessment of dynamic rock reinforcement and support testing facilities, utilised dynamic testing techniques in the form of drop tests to quantify the performance of ground support systems. [PERSON] et al., [PERSON] and [PERSON] [5,6] both concluded that whilst the results from the drop test yielded reliable results, these were limited because of the inability to model in-situ conditions and that further testing should be conducted in a capacity that could achieve this. Due to the nature of drop testing, which imparts a singular direct heavy blow, in-situ rock conditions, such as rock mass, stress and boundary conditions are not considered [2, 6, 7, 8]. [PERSON], [PERSON] and [PERSON] [2, 8] highlighted that a critical limitation of the drop test is the physical size restriction of the testing facility. Despite the Western Australia School of Mines (WASM) developing a dynamic testing rig which overcomes this restriction, the dynamic facility does not use a free moving mass impacting a stationary element but instead uses a moving test body, which impacts an energy distribution device or stationary body. In [PERSON] [6] and [PERSON]'s [6] analysis of the effectiveness of drop tests, they compared several facilities, such as:  
* Terratek;
* SRK Drop Weight Test Facility;
* SIMRAC Dynamic Stop Test Facility;
* SRK/Duraset Wedge-Block Loading Device;* GRC Weight Drop Test;
* Noranda Technology Centre/CANMET Dynamic Testing Apparatus;
* WASM Dynamic Testing Facility;
* MIRARCO Impact Test. They note that these testing facilities are considered quite poor as they mostly rely on direct impact testing and therefore do not reflect in-situ rock conditions. Whilst they provide a good indication of the support strength of the element itself, they do not adequately simulate the behaviour of support systems under dynamic loading. A benefit of the drop test is that they are generally repeatable and can provide consistent results. The WASM testing facility is significantly larger and capable of imparting a more significant load and is considered to be the most advanced drop testing facility, however, it cannot overcome the inability to replicate in-situ rock conditions. This is a fundamental flaw of the nature of drop tests. Despite the limitations of the drop test, this testing method is still widely used. Similar to [PERSON], [PERSON] and [PERSON] [9], [PERSON], [PERSON] and [PERSON] [10] also utilised a static test facility to test varying steel types and examined various connection types noting that it yielded beneficial results. Whilst many have attempted to use the drop test to measure the capabilities of structural elements, it is widely recognised that in terms of measuring the behaviour of elements under dynamic loading that the drop test is not an ideal testing method. Table 1 below summarises the main advantages and disadvantages of drop testing [8].