Advance and review on the experimental researches of the freezing and thawing characteristics of soils

The freezing-thawing test is vital to obtain the physical parameters and to evaluate the engineering characteristics of frozen soils. In this paper, the experimental study on frozen soils is reviewed from four aspects:hydrothermal parameters, mechanical parameters, frost heaving and thaw settlement mechanisms. The main test methods and equipments of thermal-hydro-mechanical parameters are presented. The development and experimental verification of the theoretical models are summarized. The variable temperature control ability of the equipments is important for the data quality of frozen soil tests. However, the domestic manufacturing level of low temperature coolant circulation pumps with high pecision is immature in China. Freezing-thawing test systems with high performance are still mainly dependent on imports. Therefore, attention should be paid to the research and development of test equipments when the experiment and theoretical researches on frozen soils are carried out. The neural network-PID algorithm combined with the solid-state refrigeration system is capable to solve the problem of variable temperature control of test equipments. The high variable temperature control performance of the solid-state refrigeration system has the ability to simulate the complex freezing process. Combined with new sensing technologies, such as fiber optic pressure sensing technology and linear CCD scanning imaging technology, the solid-state refrigeration system can provide new experimental schemes for the frozen soil research. The improvement of the test technology can promote the research of freezing and thawing mechanism of soils and provide reference for the engineering construction in the cold regions of China. © 2022, Science Press. All right reserved.