Abstract: Soil-water characteristic curve (SWCC) plays an important role in the study of unsaturated soils, and the research of prediction method of SWCC has a great scientific significance. The nuclear magnetic resonance (NMR) tests and SWCC experiments of Wuhan clay samples with different dry densities were carried out; Fredlund-Xing model was used to analyze SWCC experimental data and the complete SWCCs of total matric suction range were obtained. The theoretical relationship formula between matric suction and T2 value was established combining KST model and Young-Laplace theory. Based on the SWCC and NMR experimental results, the presented theoretical formula was tested. However, the test results show that this theoretical formula cannot effectively and simply describe the relationship between matric suction and T2 value. Through conversion and comparing analysis of SWCC and NMR experimental results, an empirical formula between matric suction and T2 value was established and testified to be rational. On this basis, a method was put forward to predict the SWCCs of unsaturated clay with different initial dry densities through NMR technique

Key words: matric suction, soil-water characteristic curve, nuclear magnetic resonance (NMR), relaxation time