The Impact of Unfrozen Water Content on Ultrasonic Wave Velocity in Frozen Soils

According to the mixture theory and the principle of effective stress, acoustic wave equation of three-phased frozen soil was established. Through academic discussion and exponential analysis, it is obtained that the wave velocity is influenced by the soil types, ice content and water content, and decreases with an increase of water content. In order to validate the correctness of theoretical model tested the ultrasonic P-wave velocity of silty clay, silt and sand under the condition of different initial water contents and negative temperatures. Result shows that, the change of temperature causes the unfrozen water content changed and consequently causes the variation of P-wave velocity. P-wave velocity decreases with an increase of unfrozen water content and there is a good linear relation between them.