Research on Microstructure of Soft Clay under Various Artificial Ground Freezing Conditions Based on NMR

Abstract

Nuclear magnetic resonance (NMR) can help to collect soft clay pore size data. This paper uses NMR to study the effect of freezing duration, the gap time between two freezing actions and thawing temperature on the pore size distribution (PSD) in soft clay. It was found that most of the freezing and thawing progress was completed during the first two hours. A longer time gap between the first and second freezing cycles leads to greater structural damage. An appropriate thawing temperature results in less subsidence induced by the artificial ground freezing (AGF). A new method to distinguish water types for various freezing conditions is proposed. This freezing method to determine the cutoff value could fill the defect in the previous methods.

Keywords

• frozen–thawed soft clay
• soft clay
• NMR
• pore size distribution
• cutoff value
• AGF