This study experimentally estimated the fractal pore size distribution of granites, which is then linked to the hydro-mechanical properties of rocks treated by temperatures that range from 25∘C to 900∘C. The mercury intrusion experiment was carried out to characterize the pore size distributions and the MTS815.02 triaxial testing system was used to investigate hydro-mechanical properties of rocks. Finally, the micro-CT scanning system and scanning electron microscope system were employed to exhibit the evolutions of microstructures of cracks that were then linked to the macroscopic hydro-mechanical properties. The results show that the pore size distribution of granites follows the fractal scaling law and the fractal dimension ranges from 2.45 to 2.94. The fractal dimension decreases significantly when the temperature increases from 25∘C to 100∘C and then holds a constant with continuously increasing the temperature to 400∘C. The fractal dimension slightly increases as the temperature increases from 400∘C to 500∘C and decreases following a linear relationship until the temperature of 900∘C. The porosity obtained by the mercury intrusion experiment shows an exponential relationship with the fractal dimension. Both the axial stain and peak total stain, as well as the initial permeability and the permeability at the peak axial stress, have quadratic functions with the fractal dimension. The mean aperture of fractures increases from 56.75μm to 76.10μm with increasing the temperature from 100∘C to 900∘C through micro-CT scanning. The scanning electron microscope test clearly shows that the fractures are generated when the temperature exceeds 300∘C, which agrees well with the micro-CT scanning results. With increasing the temperature from 400∘C to 900∘C, both the number and aperture of fractures increase, which well interprets that both the strain and permeability increase as indicated by the triaxial stress-flow tests.

中文翻译：

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高温处理后花岗岩分形孔径分布及水力学性质的试验研究

这项研究通过实验估计了花岗岩的分形孔径分布，然后将其与在 25∘C 至 900∘C. 进行压汞实验表征孔径分布，采用MTS815.02三轴试验系统研究岩石的流体力学性质。最后，使用显微CT扫描系统和扫描电子显微镜系统来展示裂纹微观结构的演变，然后将其与宏观流体力学性能联系起来。结果表明，花岗岩的孔径分布遵循分形尺度规律，分形维数范围为2.45~2.94。当温度从 25 度升高时，分形维数显着降低∘C 到 100∘C，然后保持恒定，不断增加温度到 400∘C. 随着温度从 400 升高，分形维数略有增加∘C 到 500∘C 并按照线性关系下降，直到温度为 900∘C.压汞实验得到的孔隙率与分形维数呈指数关系。轴向应变和峰值总应变以及初始渗透率和峰值轴向应力处的渗透率都与分形维数具有二次函数。裂缝平均孔径从 56.75 增加μ米至 76.10μm 随着温度从 100 升高∘C 至 900∘C通过显微CT扫描。扫描电镜测试清楚地表明，当温度超过300℃时产生裂缝∘C，与显微CT扫描结果吻合较好。随着温度从 400∘C 至 900∘C，裂缝的数量和孔径都增加了，这很好地解释了应变和渗透率都增加了，如三轴应力-流动试验所示。