Shock-induced fracture of dolomite rock in small-scale blast tests

Abstract

This paper attempts to study dolomite failure using small-scale blast tests. The experimental setup consisted of a cylindrical specimen with a central borehole fitted with a detonation cord inside a copper pipe. The specimen was confined using lead material. During the test, acceleration histories were recorded using sensors placed on the lead confinement. The results showed that heterogeneity and initial cracks significantly influenced the observed failure and cracking patterns. The tests were numerically represented using the previously validated Johnson-Holmquist II (JH-2) constitutive model. The properties of the detonation cord were first determined and verified in a special test with a lead specimen to compare the deformation in the test with that of numerical simulation. Then, the small-scale blast test was simulated, and the failure of the dolomite was compared with the test observations. Comparisons of acceleration histories, scabbing failure, and number of radial cracks and crack density confirmed the overall repeatability of the actual testing data. It is likely that the proposed model can be further used for numerical studies of blasting of dolomite rock.

Keywords

• Johnson-Holmquist II model (JH-2)
• Rock
• Blasting
• Fracture
• Small-scale test