Abstract
Abrasive Water Jet (AWJ) technology has vast application prospects in the assisted drill-blasting of tunnel excavation, with the advantages of fast-breaking speed, low tool wear, less dust, and good mobility. Nevertheless, AWJ technology has some limitations and shortcomings, such as the small effective fracturing range and parameter mismatch, which influence the fracturing effect of AWJ. To solve the abovementioned issues, it is necessary to study the failure mechanism of rock impacted by AWJ and nozzle parameter effects on rock fragmentation. Based on the coupling algorithm of Smooth Particle Hydrodynamics and Finite Element Method (SPH-FEM), in this research, the numerical model of AWJ impacting rock was established, and the result was verified with Computed Tomography (CT) scanning after the AWJ impacting rock experiment and image processing technology. Through the analysis of the stress characteristics of typical particles in the rock model at different stages and positions, the formation and expansion mechanisms of the crater and the cracks were revealed. Additionally, in this research, the comprehensive damage factor of rock (X) representing the fragmentation degree was defined. By comparatively analyzing X-values with certain technical parameters of AWJ, the importance ranking of the nozzle parameters, the effect of each nozzle parameter on the rock fragmentation, and the optimal parameter combination were also investigated.
Highlights
A tunnel is an engineering structure for underground passage, and tunnels play an important role in communications and transportation
Abrasive Water Jet (AWJ) technology is a frontier method equipped with the advantages of fast-breaking speed, low tool wear, less dust, and good mobility, and it is suitable for the assisted drill-blasting of tunnel excavation [3]
On the basis of the coupling algorithm of Smooth Particle Hydrodynamics and Finite Element Method (SPH-FEM), this paper established the AWJ impacting rock numerical model, which was verified by the comparison of the internal and external fragmentation features of rock in the numerical simulation and the actual experiment based on the Computed Tomography (CT) and image processing technology
Summary
A tunnel is an engineering structure for underground passage, and tunnels play an important role in communications and transportation. E numerical simulation of AWJ impacting rock can be used to obtain the stress distribution and record the dynamic damage state of rock to further explore the failure mechanism and parameter effects. It involves large deformation, a high strain rate, and other complicated issues [15]. Using the SPH-FEM coupling method, Wang et al [20] carried out the numerical simulation of the water inrush of a tunnel during blasting, and Li et al [21] revealed the rock failure mechanism and the effect of confining pressure for vertical and inclined particle jet impacts.
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