A simple procedure for freezing triaxial test specimens and determining the final moisture content after liquefaction

Accurately determining the critical state line in specimens subjected to undrained triaxial tests, particularly those prone to liquefaction, relies on precise void ratio determination. Procedures exist to determine volume variations throughout all stages of the testing process until the final failure condition is reached. However, these procedures have not demonstrated the same level of accuracy as the method used for freezing the samples and subsequently determining the water content and void ratio. The conventional procedure for freezing the specimen involves placing the entire base of the triaxial system, including the tubes and valves, in a freezer. However, this process not only causes damage to the valves, requiring frequent replacement and increasing the cost of the tests but also necessitates a dedicated freezer for this specific procedure. This paper presents a simple and safe procedure for freezing specimens without detaching the base and exposing the valves and the entire system to low temperatures. The key advantage of this procedure over conventional methods is the reduction of material and time costs without compromising the accuracy of determining the void ratio. The specimen is frozen within minutes using solid carbon dioxide (dry ice), and determining water content is easily accomplished.