To investigate the variation patterns of pore seepage characteristics in roadway lining concrete designed for abandoned mine pumped storage,an analysis was conducted on the shape of liquid bridges in the capillary pores of concrete under hydraulic pressure,based on the geostress,hydraulic head,and water storage/release conditions experienced by the roadways in abandoned mine pumped storage scenarios.A theoretical model for the hydraulic seepage process in concrete was developed.The wet-dry alternation process under sustained loading conditions was simulated for concrete samples subjected to hydraulic seepage and drying cycles,utilizing an improved rock rheological disturbance apparatus,a custom-designed water pump,and silicone plates.Changes in water absorption characteristics of concrete under differ-ent load levels,hydraulic pressures,and wet-dry alternation conditions were explored,with resulting variations in permeability and pore structure analyzed using a permeameter and NMR.The results indicate that during the hydraulic seepage process,the later water absorption rate of concrete exceeds the initial absorption rate,with a positive correlation to load levels and a negative correlation to the number of wet-dry cycles.After three wet-dry cycles,the permea-bility of concrete increases in response to higher load levels and hydraulic pressures,however,after seven wet-dry cycles,an overall decline in permeability is observed as load levels and hy-draulic pressures increase.Additionally,the pore structure of the concrete undergoes a cyclical process of"matrix erosion—compression damage—secondary matrix erosion"with the increase in the number of wet-dry cycles,where hydraulic pressure plays a promoting role in this process.
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