(1. Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines，Northeastern University，Shenyang，Liaoning 110819，China；2. Center for Rock Instability and Seismicity Research，Northeastern University，Shenyang，Liaoning 110819，China)
Abstract：By using the pendulum hammer driven SHPB apparatus，the ideal incident waveform is generated by changing the shape and by controlling the impact velocity of the pendulum hammer. The compressive test and Brazilian test of sandstone specimens were conducted using the pendulum hammer driven split Hopkinson pressure bar(SHPB) apparatus，and the variation of dynamic compressive strength and dynamic tensile strength under different impact velocity of the pendulum hammer is examined. The strain rate ranging from 100/s to 102/s，which is generally considered as intermediate strain rate，is measured during the dynamic compression test，and the loading rate corresponding to the tensile stress at center of rock disc，ranging from 100 GPa/s to 400 GPa/s，are generated during the dynamic Brazilian test. The dynamic compressive strength and dynamic tensile strength of the sandstone samples increase with the impact velocity，showing an obvious strain-rate dependency. During the dynamic Brazilian test the sandstone samples were finally separated into two halves along the loading diameter. The V-shaped failure zone at the contact area between the incident and transmitted bars and the rock specimen becomes larger with the increasing impact velocity. The advantage of the pendulum hammer driven SHPB apparatus is that the ideal incident stress waveform can be excited by the pendulum hammer，and it can supply a feasible experimental method to measure the dynamic strength and failure process of the rock under the intermediate strain rate.
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2014, Vol. 33 
