Analysis on the fragment and energy dissipation of deep sandstone after high / low temperature treatment in SHPB tests

Dynamic failure characteristics of deep sandstone exposed to different temperatures treatment from -15 ℃ to 1 000 ℃ were studied by using the split Hopkinson pressure bar ( SHPB) apparatus of 50 mm in diameter at room temperature. The relationships among incident energy,absorbed energy,specific energy absorption value,mass fractal dimension of fragmentation and average fragment size after different temperatures conditions were obtained. The influ- ence of temperature on the failure degree and energy dissipation of deep sandstone was analyzed. The results show that the temperature has a significant effect on rock fragmentation and energy dissipation,and 20 ℃ is the boundary point with the temperature rang from -15 ℃ to 1 000 ℃ . From -15 ℃ to 20 ℃ ,both the mass fractal dimension of frag- mentation and the average fragment size of sandstone increase with the increase of temperature,however,both of them decrease with the increase of temperature from 20 ℃ to 1 000 ℃ . The temperature treatment has similar effects on the incident energy,absorbed energy and specific energy absorption,and the boundary points for -15 ℃ to 20 ℃ and 20 ℃ to 1 000 ℃ are -5 ℃ and 400 ℃ ,respectively. When the temperature treatment is smaller than the boundary points,the incident energy,absorbed energy and specific energy absorption increase with the increase of temperature treatment,yet they decrease with the increase of temperature treatment when the temperature treatment is larger than the boundary points.