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Abstract Based on the scientific understanding of deep rock under high in-situ stress and dynamic excavation disturbance，the experiments on dynamic failure characteristics of sandstone under one-dimensional coupled static and dynamic loads were conducted with a modified split Hopkinson pressure bar(SHPB). Four cases，without axial pre-compressive stress and with three levels of axial pre-compressive stress，were designed to conduct impact tests under different strain rates. The results show that，at the same strain rate，the dynamic response of rock is influenced obviously by axial pre-compressive stress ratio. When the strain rate is a constant，the impact compressive strength first increases and then decreases as the axial static pre-stress increases；and it reaches the maximum value when the axial pre-compressive stress ratio is 0.6～0–0.7. When the axial static pre-stress is a constant，the impact compressive strength increases with an exponential function as the strain rate increases. Within a certain range of axial pre-compressive stress ratios，the incident energy will influence the dynamic impact energy response of rock specimen；and the specimen will experience three phases of absorb energy-release energy-absorb energy when the axial compressive stress ratio increases. The transformation mechanism of dynamic strength increase，rock burst and induced fracture of rock under high in-situ stress can be explained better by the above three phases. The results can also provide a theoretical guide for the deep rock engineering practice.
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Received: 12 May 2010
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2010, Vol. 29 
