Abstract The behavior impacting failure and dynamic mechanical properties of granite exposed to high temperature have been researched with high-temperature split Hopskinson pressure bar(SHPB) system and ultrasonic detector SRM–5N. The scope of this research includes the variation of longitudinal wave velocity,waveform,dynamic compressive strength and peak stress with the temperature. The temperature varies in the range of 25 ℃,100 ℃,200 ℃,400 ℃,600 ℃,800 ℃,1 000 ℃,and the heating velocity is 10 ℃/min. The results are as follow:(1) Generally speaking,the thermal damage of granite gradually raises with the temperature increasing. But it decreases before 100 ℃,Then enhancement of thermal damage is not drop slowly until exposed to 600 ℃. (2) As a whole,the dynamic compressive strength of granite is diminution and peak strain is enlarge when the temperature is enhanced,but it is opposition with them before 110 ℃. And dynamic compressive strength is obviously reductive and peak strain is obviously enhancive after 600 ℃. (3) It is suggested that 110 ℃ is a temperature threshold of granite,before this temperature,the thermal damage of granite is minus,the dynamic compressive strength decreases. And suggested another temperature threshold is 600 ℃– 800 ℃,the dynamic mechanical properties of granite changed obviously beyond this temperature. The research method and conclusions can provide references for rock project construction and fireproofing designs.
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Received: 10 May 2012
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