Heat transfer in jointed rock masses exhibits characteristics of discontinuous, heterogeneous, and anisotropic due to the effects of rock discontinuities. In this work, thermal contact resistance (TCR) evolution of granite joints under normal stress was investigated. A novel method was proposed for the measurement of TCR for rough rock joints. A numerical calculation program was established for the determination of contact area based on the initial morphology of the joint surfaces and the monitored joint closure during the experiment. An estimation model of TCR for granite joints based on the equivalent joint aperture was established. It is found that TCR of granite joints shows decreasing trend with normal stress. The decreasing rate is relatively large at the initial loading stage and gradually reduces with normal stress. The values of TCR eventually stabilize. TCR of granite joint has no obvious correlation with joint roughness coefficient. It is more significantly affected by the contact area. Plastic deformation and rupture of the micro-convex body on the joint surfaces occurred due to the application of normal stress, which improve the heat transfer efficiency and lead to the decrease in TCR. In general, predication results of the TCR estimation model show good consistency with the experimental data. The model is more suitable for the cases with small joint apertures. This study can provide knowledge to the better understanding of heat transfer in rock masses containing different kinds of discontinuities.

由于岩石不连续性的影响，节理岩体的传热表现出不连续、非均质和各向异性的特点。在这项工作中，研究了正应力下花岗岩节理的热接触阻力（TCR）演变。提出了一种测量粗糙岩石节理 TCR 的新方法。根据接头表面的初始形态和实验过程中监测到的接头闭合情况，建立了数值计算程序来确定接触面积。建立了基于等效节理孔径的花岗岩节理TCR估算模型。研究发现花岗岩节理的TCR随法向应力呈减小趋势。初始加载阶段下降率较大，随着正应力逐渐减小。TCR 值最终趋于稳定。花岗岩节理TCR与节理粗糙度系数无明显相关性。受接触面积的影响更为显着。由于施加法向应力，接合面上的微凸体发生塑性变形和破裂，提高了传热效率，导致TCR下降。总体而言，TCR估计模型的预测结果与实验数据具有良好的一致性。该模型更适合接头孔径较小的情况。这项研究可以为更好地理解含有不同类型不连续性的岩体中的传热提供知识。由于施加法向应力，接合面上的微凸体发生塑性变形和破裂，提高了传热效率，导致TCR下降。总体而言，TCR估计模型的预测结果与实验数据具有良好的一致性。该模型更适合接头孔径较小的情况。这项研究可以为更好地理解含有不同类型不连续性的岩体中的传热提供知识。由于施加法向应力，接合面上的微凸体发生塑性变形和破裂，提高了传热效率，导致TCR下降。总体而言，TCR估计模型的预测结果与实验数据具有良好的一致性。该模型更适合接头孔径较小的情况。这项研究可以为更好地理解含有不同类型不连续性的岩体中的传热提供知识。该模型更适合接头孔径较小的情况。这项研究可以为更好地理解含有不同类型不连续性的岩体中的传热提供知识。该模型更适合接头孔径较小的情况。这项研究可以为更好地理解含有不同类型不连续性的岩体中的传热提供知识。