(1. State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;2. School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;3. School of Architecture and Civil Engineering,Nantong University,Nantong,Jiangsu 226019,China)
Abstract:Temperature is one of the important factors influencing the physical properties of rock. In order to obtain the effect of temperature on the pore size distribution in rock material,the mercury intrusion porosimetry was adopted to test the pore characteristics of granite samples after high temperature treatment of 25 ℃–1 200 ℃. The fractal structure and model of pore size distribution under different high temperatures were then studied. The results showed that the rock porosity increased exponentially with the rising heating temperature and 500 ℃–800 ℃ was a threshold temperature interval. The porosity increased only 50% below 500 ℃ and about 3 to 5 times from 500 ℃ to 1 200 ℃. Most of the new pores and cracks induced by the high temperature are meso pores with the average diameter between 1 μm and 10 μm. The meso pores account for about 15% when the heat temperature is lower than 500 ℃,and then increases steadily and reaches 28.24% at 800 ℃,more than 40% over 1 000 ℃,and its volume increases by 11.8 times. The pore size distribution of rock under different temperatures exhibits a good statistical fractal feature with the pore fractal dimension between 2.99 and 3. With the rising of the temperature,the fractal dimension decreases more and more,which shows that the uniformity of pore distribution is raised. The model by ZHANG Jiru and TAO Gaoliang are proved better than the one of Friesen model based on ideal Menger sponge in predicting the rock porosity of different pore size.
张志镇1,2,高 峰1,2,高亚楠1,2,徐小丽1,2,3,侯 鹏1,2,滕 腾1,2,尚晓吉1,2. 高温影响下花岗岩孔径分布的分形结构及模型[J]. 岩石力学与工程学报, 2016, 35(12): 2426-2438.
ZHANG Zhizhen1,2,GAO Feng1,2,GAO Yanan1,2,XU Xiaoli1,2,3,HOU Peng1,2,TENG Teng1,2,SHANG Xiaoji1,2. Fractal structure and model of pore size distribution of granite under high temperatures. , 2016, 35(12): 2426-2438.
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