Abstract The evolution of the permeability of granite at high temperatures has a significant effect on geothermal exploitation. In this study, the fluid-solid coupling algorithm is improved based on the different intra-granular, inter-granular and crack seepage characteristics of granite, and the permeability characteristics of thermally treated granite specimens are simulated under different confining pressures. The results show that the permeability of granite non-linearly decreases with confining pressure in a concave type and its variation with temperature is similar to the experimental results. When T ≤ 300 °C, temperature has a slight effect on the variation of permeability. Because the temperature has a slight effect on the distribution characteristics of the flow rate and pore pressure, the flow rate mainly dependent on the inter-granular contact, which is parallel to the gradient of pore pressure. However, when T ≥ 450 °C, the number of thermally induced cracks increases and forms a coalesced channel; thus, the permeability increases with temperature. The temperature has a significant effect on the distribution characteristics of the flow rate and pore pressure. Confining pressure can decrease the permeability, whereas it has a slight effect on the distribution of flow rate and pore pressure in the specimen.

中文翻译：

---

花岗岩热处理后渗透率演化数值模拟

摘要 高温下花岗岩渗透率的演变对地热开发具有重要影响。本研究根据花岗岩不同的粒内、粒间和裂缝渗流特性，改进流固耦合算法，模拟不同围压下热处理花岗岩试件的渗透特性。结果表明，凹型花岗岩渗透率随围压非线性降低，其随温度的变化与实验结果相似。当T≤300℃时，温度对磁导率变化的影响很小。由于温度对流速和孔隙压力的分布特性有轻微影响，流速主要取决于粒间接触，与孔隙压力梯度平行。然而，当 T ≥ 450 °C 时，热致裂纹数量增加并形成聚结通道；因此，渗透率随温度增加。温度对流速和孔隙压力的分布特性有显着影响。围压可以降低渗透率，但对试样中的流速和孔隙压力分布影响较小。温度对流速和孔隙压力的分布特性有显着影响。围压可以降低渗透率，但对试样中流速和孔隙压力的分布影响较小。温度对流速和孔隙压力的分布特性有显着影响。围压可以降低渗透率，但对试样中的流速和孔隙压力分布影响较小。