Temperature effect on hydro-physical properties of clayey soils

Temperature has great influence on the hydro-physical properties of clayey soils, such as Atterberg limits, swelling and permeability. This temperature effect may be distinct among different types of soils. In order to systematically study the regularity and mechanism of the effect, this research is conducted to evaluate the adsorbed water content, Atterberg limits, swelling and permeability through laboratory study in the range of 5 ℃ -50 ℃ , among three common types of clayey soils in Nanjing with different mineral compositions. The results indicate that the liquid limit reduces, the swelling increases, the permeability increases with rising temperature, and the temperature effect is fundamentally due to the change of adsorbed water content. Hydrophilic minerals, which contain large amounts of adsorbed water, play an important role in the temperature effect. With the increase of hydrophilic minerals, the temperature effect on the liquid limit increases and the effect on the swelling ratio decreases. The content of the hydrophilic minerals has significant impact on the temperature effect of permeability. The results of adsorbed water content show that the adsorbed water transports to penetrate water and free water when temperature rises, and permeability may increase by tenfold. It indicates the laws and mechanism of the temperature effect on three basic hydro-physical properties of clayey soils, which provides a theoretical basis for assessment and prevention of corresponding geological hazards.