Experimental and Numerical Studies on Splitting Fracture of Rocks Using Different Bit Heads

초록

A hydraulic splitting method was recently developed to reduce the generation of noise and vibration in urban underground construction. However, research on optimizing the method considering the shape of the hydraulic splitting machine or the rock type has yet to be conducted sufficiently. Herein, experimental and numerical investigations were conducted to identify the crushing performance of six types of bit heads on three kinds of rocks (granite, marble, and sandstone). The uniaxial and triaxial compressive test, Brazilian test, and semicircular bend (SCB) test were conducted to investigate the physical properties of the rocks. Simultaneously, the splitting fracture of the rocks was investigated depending on the shape of the bit head. The test results showed that the failure of the specimens was controlled by the tensile strength of the rock, while the failure mode was governed by the type of the bit heads. Based on the test results, a damage-plasticity model was used to simulate the failure test by introducing double damage variables. Consequently, the numerical simulations effectually replicated the failure modes of the splitting fracture of the rock samples by the different bit heads.

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