On the frost heaving-induced pressure response and its dropping power-law behaviors of freezing soils under various restraints

A one-dimensional frost heave testing system is developed in this paper to investigate the frost heaving-induced pressure (FHIP) of frost susceptible silty clay under various restraints and thermal gradients. The evolution of the frost heave, the moisture migration, and the FHIP are examined from the conducted freezing tests, as well as the effects of restrained stiffness and thermal gradient. The development of frost heave can be divided into four stages, i.e. the constant temperature stage, the rapid development stage, the transition development stage, and the stable stage. For tests with -20 degrees C at the cold end of the tested samples, the ultimate heave is 5.88 mm, 4.86 mm and 4.31 mm, and the FHIP is 65.0 kPa, 71.1 kPa and 92.1 kPa, corresponding to the restrained stiffness of 11.06 kPa/mm, 14.62 kPa/mm and 21.36 kPa/mm, respectively. It can be found that the frost heave decreases gradually with the restrained stiffness, whereas the FHIP shows an increase with the retrained stiffness. The results indicate that the FHIP drops rapidly with the relaxation of restraints, while this downward trend slows down as the frost heaving ratio increases. It is found that the FHIP decreases following an exponential function with the increase of frost heaving ratio, and the FHIP shows a dropping power-law behavior with an exponent of approximately 8/5.