ABSTRACT
Assessment of the potential for static or cyclic liquefaction of loose sand requires information on the undrained response of the deposit. Undisturbed samples of loose sand deposits are necessary to properly obtain this undrained response, which is a function of the in-situ state of the deposit and the applied stress path during loading. In-situ ground freezing for sampling which preserves the in-situ void ratio and fabric is described in this paper. Its application at six sites during the Canadian Liquefaction Experiment (CANLEX) are described to illustrate the challenges in the field and to outline how the different site conditions were managed. The techniques to freeze the ground, to obtain and preserve samples and to prepare laboratory test specimen are described along with a recommended procedure to thaw the frozen laboratory test specimen without disturbing the in-situ condition. The frozen core and in-situ field tests at the sites illustrate the extreme hetergeniety of sands placed hydraulically by man or nature. This variability is a challenge for the experimentalist to capture the material behavior and then incorporate this into an economical design.
