Freeze–thaw process of soil between two piles as monitored by piezoelectric ceramic sensor

Freezing process of specimens in freeze–thaw cycle

The moisture content of the clay samples was 10%, 15%, 20%, 25%, and 30%. When the temperature dropped to 0 °C, the testing times were approximately 72 min, 105 min, 120 min, 150 min, and 156 min, respectively, as shown in Figs. 2 and 3. The moisture content of the medium sand samples was 10%, 15% and 20% respectively, and the test times were approximately 75 min, 129 min, and 135 min, respectively, when the temperature dropped to 0 °C, as shown in Fig. 3. Then, the temperature was lowered from 0 °C to − 15 °C, and the…