Research on the Pore Water State During the Drying Process of Bentonite Based on NMR
In order to investigate the evolution process of pore water and the kinetic properties of soil-water interaction during the drying process of GMZ bentonite,the T2 distribution curve and two-dimensional T1-T2 spectrum of the soil were measured using nuclear mag-netic resonance(NMR)technology.The evolution law of pore water in the soil during the drying process was described by combining the T2 distribution curve with the soil water characteristic curve(SWCC).The study reveals that during the drying process,pore water in the soil is discharged from larger pores with higher chemical potential to smaller pores with lower chemical potential.Through the two-dimensional T1-T2 correlation test,the surface residence time(τs)and surface affinity coefficient of water molecules on the soil particles during the drying process were determined based on the Broadband Proton Pulses(BPP)model and the NMR two-dimensional diffusion model.The results show that during the drying process,the surface residence time(τs)of water molecules increases with the decrease of water potential,indicating enhanced adsorption of water molecules on the soil particle surface and decreased mobility of wa-ter molecules.
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