Experimental Study on the Dynamic Characteristics of Frozen Silty Clay and Its Influencing Factors

Frozen soils are widely distributed in the seismically active regions of northwest China. Under the background of global warming, the study of the dynamic characteristics of frozen soil is very significant for the sustainable development of engineering in cold regions. In this study, the silty clay in the Lanzhou area of northwest China is selected to investigate the dynamic characteristics and its influence factors by dynamic triaxial tests. Various influence factors were considered, including confining pressure, soil temperature, soil water content and loading frequency. The dynamic elastic modulus ratio and reference dynamic strain amplitude increase as confining pressure and soil temperature decrease, and they also increase as soil water content and loading frequency increase. With an increase in confining pressure, soil water content, loading frequency, and a decrease in soil temperature, the damping ratio decreases but the maximum dynamic elastic modulus increases. With an increase in dynamic strain amplitude, the dynamic elastic modulus ratio has a decreasing trend, while the damping ratio has an increasing trend. It was found that the dynamic behaviors are most sensitive to the soil temperature. In addition, the comprehensive influence effect of soil water content, confining pressure, soil temperature, and loading frequency on the maximum dynamic elastic modulus, maximum damping ratio, and reference dynamic strain amplitude of frozen silty clay are analyzed, and the quantitative relationships between them are established. The results can provide evidence for seismic design and safe operation and maintenance of infrastructure in cold regions.