ABSTRACT:

The dynamic compressive tests were carried out on plate-shape marble specimens with different types of single hole in the central of the specimen by the Split Hopkinson Pressure Bar (SHPB) apparatus. The dynamic crack propagation processes were monitored by using a real-time controlled high speed camera. The dynamic strength and crack propagation characteristics were analyzed and discussed. Meanwhile, a simple and effective method was proposed to measure the average crack propagation velocity of marbles under impact load. The average dynamic crack propagation velocity of the marble specimens ranges in 100–450 m/s at the loading rate of 30–45 s−1.

1 INTRODUCTION

The crack behavior around single hole rock specimen has been extensively studied under static or quasi-static loading by both experimental and numerical methods. For example, Dyskin et al. (2003) studied the influence of shape and locations of initial 3-D cracks on their growth in uniaxial compression. Klein & Reuschle (2004) proposed a pore crack model to compare theoretical results with laboratory data obtained on four sandstones which were tested under conventional triaxial compression conditions with confining pressures between 0 and 35 MPa. The comparison showed that by using a small number of parameters (pore size, pore density, fracture toughness, and elastic moduli), the model was able to predict the rock behavior during the compressive tests and the stress level at rupture was consistent with the observations in a quite accurate way when the micro structural parameters were introduced. Tang et al. (2005) used MFPA2D (material failure process analysis) to numerically study the mechanisms of compression-induced axial splitting cracks for heterogeneous solids containing pre-existing single, triple and multi-pore-like flaws. Various parameters, such as the hole diameter, the specimen width, and the geometrical arrangement of hole locations, were quantitatively used to characterize the crack growth process. Ma et al. (2006) investigated the failure process of a plate marble specimen containing a central hole by using specially designed deformation field inspection system (Geo-DSCM system), which showed that the deformation field was localized on the sections in tension at the early stage of loading.

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