| Budget Amount *help |
¥4,030,000 (Direct Cost: ¥3,100,000、Indirect Cost: ¥930,000)
Fiscal Year 2020: ¥650,000 (Direct Cost: ¥500,000、Indirect Cost: ¥150,000)
Fiscal Year 2019: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2018: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000)
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| Outline of Final Research Achievements |
We experimentally investigated the fracture of rock specimens based on changes in pore-size distribution, P-wave velocity, and the occurrence of acoustic emission (AE). Three rock types which are often used as stone materials were used in the experiment. We repeatedly subjected the rock specimens to changes from 4℃ to 84℃ using a temperature-controlled chamber at a rate from ±4℃/min to ±0.5℃/min. Consequently, the P-wave velocity decreased by approximately 5%, 28%, and 2% for the granite, marble, and sandstone, respectively. Furthermore, the pore-size distribution changed by approximately 5-6% and 16% for the granite and marble, respectively. The variation in pore size of the sandstone was negligible. The occurrence of AE was detected in all rock types, but its amplitude for the granite was the largest, followed by the marble and sandstone, respectively. Therefore, a low-temperature thermal cycle causes thermo-mechanical fracture inside rocks.
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