Experimental Study on Ice Melting and Hydraulic Properties in Ice‐Filled Fractures Under Warming Conditions

In cold mountain regions, climate warming is driving the melting of ice‐filled fractures, significantly influencing local hydrological cycles and geological activities. However, thermal‐hydraulic (TH) coupling responses within these fractures during warming remain poorly understood. To address this, we conducted numerous visualized experiments of TH processes in ice‐filled fractures with diverse geometries and flow conditions. A novel volume‐based phase segmentation method was developed to track flow channel dynamics during ice melting. The results show that ice melting dynamically alters fracture permeability, which evolves through two distinct patterns: increase‐stabilization and increase‐decrease‐stabilization. We established constitutive relations between apparent permeability and ice content, identifying two characteristic evolutionary modes during ice melting: an early‐response type (deceleration followed by acceleration) and a late‐response type (acceleration followed by deceleration). Furthermore, we uncovered how fracture transmissivity is controlled by flow channel geometry during ice melting. Channel width evolution moderates transmissivity in a sub‐linear manner, while aperture changes enhance it following a super‐cubic scaling law. Finally, the study summarizes the intertwined and temporally asynchronous nature of TH coupling in ice‐filled fractures. These insights contribute to a deeper understanding of groundwater flow in frozen fractured aquifers and have important implications for water resource management in warming cold regions.