... impact on the thermal performance of BHEs [2-3].In addition, as one of the most complex and important of the properties of porous media, the permeability is also indispensable in many other applications, ... the thermal performance of BHEs. This paper presented a novel method determining the hydraulic permeability of sand layer using the theory of capillary rise (CR). In this method, based on the ... Due to the neglect of the dynamic saturation gradients, the steep saturation gradients near the front at early time decayed at later stages. Therefore, for the long-term CR process, the Washburn...