Numerical investigation of rock damage induced by bilateral–groove-slot shaped charge blasting under the influence of in-situ stresses

Abstract

Blasting using shaped charge forms is widely extended to rock engineering. This study conducted numerical investigations to elucidate how in-situ stresses affect the damage patterns in rock blasting with Bilateral–Groove-Slot Shaped Charges (BGSSC). An innovative user-defined constitutive model was developed, which includes the modified Mohr-Coulomb strength criterion, combining the maximum tensile stress criterion, the strain rate effects of tensile/compressive strength, and tensile/compressive damage factors. The model was implemented into the ANSYS/LS-DYNA program and validated through a numerical simulation of Laurentian Granite rock blasting, thereby improving the feasibility of simulating rock blasting damage. Using the novel user-defined material model, three new computational models of BGSSC blasting in rocks were developed to investigate damage under uniaxial static compression/tension and varying lateral pressure coefficients. These models revealed the formation of continuous cracks and scattered damage, phenomena that were previously challenging to capture. The results show that, uniaxial compressive in-situ stress can suppress scattered damage across all cases, while tensile in-situ stress affects scattered damage depending on shaped charge orientations. The main cracks under different shaped charge orientations do not totally exhibit monotonic changes with vertical in-situ stress. Furthermore, both damage range ratios and effective stress attenuation coefficients are significantly affected by lateral pressure coefficients, which present diverse variation trends due to different shaped charge orientations. A constant lateral pressure coefficient sees the attenuation coefficient first increase and then decrease with the shaped charge orientation from 0° to 90°. This study may help develop more effective blast-induced damage prediction and control technologies.