Preparing Very Loose Granular Triaxial Specimens by Ex Situ Freezing

Ex situ soil freezing can be used to prepare very loose cohesionless triaxial specimens that can be handled, stored, and transported. This paper describes two freezing techniques, freezing with cold air in a freezer and freezing with liquid nitrogen. These methods are used to prepare very loose saturated Ottawa sand specimens. Special equipment and techniques used for each method are described. The advantages and disadvantages of both methods and the effectiveness of the efforts to minimize disturbance due to volume changes during freezing are discussed. Properties of specimens prepared using each method are presented. The results of 16 consolidated undrained triaxial shear tests are presented. The freezing method affects the amount of volume change during freezing but does not significantly affect the effective angle of internal friction.