The thermal conductivity of fractured rock masses is an important parameter for the analysis of energy geosystems, yet, its measurement is challenged by specimen size requirements. Fluids within fractures have lower thermal conductivities than rock minerals and heat flow lines constrict through contacting asperities. Together, heat flow constriction and phonon boundary scattering cause an apparent temperature discontinuity across the fracture, typically represented as a thermal contact resistance. We investigate the thermal contact resistance in fractured limestone and its evolution during loading and unloading (σ’=10 kPa to σ’=3000 kPa) for clean and gouge-filled fractures, under both air-dry and water-saturated conditions. The fracture thermal contact resistance decreases during loading because of the increase in the true contact area, gouge and asperity crushing, and fracture filling by produced fines that contribute new conduction pathways. These processes convey high stress sensitivity and loading hysteresis to the fracture thermal contact resistance. Water fills the fracture interstices and forms menisci at mineral contacts that significantly improve heat conduction even in partially saturated rock masses. The rock mass effective thermal conductivity can be estimated by combining the intact rock thermal conductivity with measurements of the thermal contact resistance of a single fracture under field boundary conditions.

裂隙岩体的热导率是分析能源地球系统的重要参数，但是，其测量受到标本尺寸要求的挑战。裂缝内的流体的热导率比岩石矿物低，并且热流线会通过接触凹凸而收缩。热流收缩和声子边界散射共同导致裂缝两端的明显温度不连续性，通常表示为热接触电阻。我们研究了在风干和水饱和条件下，干净和充满切屑的裂缝在破裂的石灰岩中的热接触电阻及其在装卸过程中的演化（σ'= 10 kPa至σ'= 3000 kPa）。由于实际接触面积的增加，在加载过程中断裂热接触电阻降低，产生的细粉会破坏新的传导途径，从而使凿孔和凹凸不平破碎，并填充裂缝。这些过程向断裂热接触电阻传递了很高的应力敏感性和加载滞后。水充满裂缝间的缝隙并在矿物接触处形成弯液面，即使在部分饱和的岩体中也能显着改善热传导。可以通过将完整的岩石热导率与场边界条件下单个裂缝的热接触电阻的测量值相结合来估算岩体的有效热导率。水填充裂缝缝隙并在矿物接触处形成弯液面，即使在部分饱和的岩体中也能显着改善热传导。可以通过将完整的岩石热导率与场边界条件下单个裂缝的热接触电阻的测量值相结合来估算岩体的有效热导率。水填充裂缝缝隙并在矿物接触处形成弯液面，即使在部分饱和的岩体中也能显着改善热传导。可以通过将完整的岩石热导率与场边界条件下单个裂缝的热接触电阻的测量值相结合，来估算岩石有效热导率。