Abstract: In this paper, the concept and characteristics of bound water in clayey soils are described. Representative methods of measuring the bound water content in clayey soils are introduced in detail. These methods are volumetric flask method; isothermal adsorption method; thermal analysis method; qualitative analysis method; nuclear magnetic resonance (NMR) method and theoretical formula method. Both advantages, disadvantages, characteristics and influencing factors of these methods are also discussed. It is found that the comparison of the bound water content obtained by different measurement methods is generally as follows: theoretical formula method<isothermal adsorption method≈thermal analysis method<volumetric flask method. A large number of test results prove that the results obtained by the comprehensive measurement methods using the isothermal adsorption method and the thermal analysis method are more accurate. Finally, the factors influencing the bound water content in clayey soils are summarized. It can be predicted that all methods have some limitations, and the rapid and accurate measurement of the bound water content in clayey soils is the future development direction.

Key words: Clay, Bound Water, Test Method, Applicability, Influencing Factors