The excavation performance of Water Jet (WJ) technology is affected by many parameters. Therefore, many experiments are required for the development and application of WJ technology. If a realistic numerical simulation of WJ excavation could be produced, we might be able to identify the optimum conditions for excavation, which could reduce the cost of developing new WJ technology. In this study, we focused on the Smoothed Particle Hydrodynamics (SPH) method, which is a type of particle method, for the numerical simulation of WJ excavation of soft rock saturated with water. The main results can be summarized as follows:
We developed a three-dimensional SPH simulation code for WJ excavation of soft rock saturated with water.
We clarified the usefulness of this numerical simulation code by comparing the calculated results with those from excavation experiments in soft rock saturated with water.
Water jet (WJ) technology is an effective approach to rock excavation. WJ can be used inmany fields, such as in the precision machining of solid materials, medical fields and the food industry. In WJ technology, many parameters influence excavation performance. These parameters include the driving pressure, ambient pressure, nozzle geometry, standoff distance, presence or absence of an abrasive, the properties of the excavated material, etc. Therefore, many experiments are necessary for the development and application of WJ technology. However, both the cost and time needed to develop new WJ technology increase with an increase in the number of experiments required. If a realistic numerical simulation of WJ excavation could be produced, we might be able to identify the optimum conditions for excavation rapidly and at low cost, and thus reduce the overall cost of developing WJ technology.
The WJ excavation of rock is a moving boundary problem in which water penetrates the rock, since the interfaces between the solid and liquid are greatly deformed. Therefore, in this study, we used the SPH (Smoothed Particle Hydrodynamics) method (Monaghan 1988), which is a particle method, to numerically simulate the WJ excavation of rock. The SPH method was originally developed to model astrophysical phenomena, and was later widely extended to problems involving continuum solid and fluid mechanics (Liu & Liu 2003). The SPH method is now being applied in various fields, such as in the analysis of the impact of a solid (Komurasaki et al. 1998, Shintate & Sekine 2002) and in the analysis of the large deformation of a solid (Cleary et al. 2006).