• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.5
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• pp.533-551
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• 2015

The rock fracturing during waterjet cutting is very complicated because rock is inhomogeneous and anisotropic, compared with artificial materials (e.g., metal or glass). Thus, it is very important to verify the effects of rock properties on waterjet rock cutting performance. Properties affecting the rock cutting efficiency have been variously described in the literature, depending on the experimental conditions (e.g., water pressure, abrasive feed rate, or standoff distance) and rock-types studied. In this study, a rock-property-related literature review was performed to determine the key properties important for waterjet rock cutting. Porosity, uniaxial compressive strength, and hardness of the rock were determined to be the key properties affecting waterjet rock cutting. The results of this analysis can provide the basic knowledge to determine the cutting efficiency of waterjet rock cutting technology for rock excavation-related construction.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.7
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• pp.44-50
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• 2009

High-pressured jetting is now widely used in the advanced cutting processes of polymers, metals, glass, ceramics and composite materials because of some advantages such as heatless and non-contacting cutting. Similarly to the focused laser beam machining, it is well known as a type of high-density energy processes. High-pressured jetting is going to be developed not only to minimize the cutting line width but also to achieve the short cutting time as soon as possible. However, the interaction behavior between a work piece and high-velocity abrasive particles during the high-pressured jet cutting makes the impact mechanism even more complicated. Conventional high-pressured jetting is still difficult to apply to precision cutting of micro-scaled thin work piece such as thin metal sheets, thin ceramic substrates, thin glass plates and TMM (Thin multi-layered materials). In this paper, we proposed the advanced high-pressured jetting technology by introducing a new abrasives supplying method and investigated the optimal process conditions of the cutting pressure, the cutting velocity and SOD (Standoff distance).

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.3
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• pp.167-181
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• 2021

New type of rock excavation method using a waterjet system is being developed to secure economic feasibility and to reduce vibrations during excavation. In waterjet rock excavation, overlapping of cutting width is essential for high efficiency. In this study, cutting experiments for granite specimens were performed using abrasive waterjet system according to the overlapping ratio and standoff distance. Based on the experimental results, the granite cutting performance was analyzed according to the overlapping ratio. In addition, removal shapes of the cross-section were analyzed in terms of the cutting depth, width, and volume after waterjet cutting. When the overlapping ratio is less than 58%, rock specimens are partially removed due to the insufficient overlapping ratio. However, when the overlapping ratio exceeds 67%, overcutting phenomenon is observed. For the partial overlapping ratio (i.e., 25~75%), cutting efficiency is increased in the removal volume. This study is expected to be used as the important basic data for determining the optimum overlapping ratio when the waterjet system is applied for rock excavation.