Study on pore-water pressure variation and deformation characteristics of warm frozen soils under confined dynamic loading

Abstract

Warm frozen soil is currently the subject of research by many researchers in cold regions. Its highly unstable mechanical properties, particularly its dynamic properties, play an essential role in the instability of frozen soil foundations. The deformation of warm frozen soils and pore-water pressure are related, the confined compression tests under dynamic load were performed to clarify the relationship between them. And the variation law of pore-water pressure and deformation in frozen soils under the effect of four factors: temperature, dynamic stress amplitude, dry density and frequency were discussed, and the mechanism of pore-water pressure and deformation is also elaborated. The results show that the pore-water pressure of frozen soils varies greatly during the test, with a general three-stage pattern of increasing-dissipating-increasing. And the deformation of frozen soil has a significant regularity, and the overall variation trend is rapid increase followed by dynamic stability or slow growth. Meanwhile, creep and consolidation deformation are important components of frozen soil deformation, and the deformation generated by both in the test basically accounts for about 50% or more of the total deformation, and in some cases even up to about 64%. In addition, it is indicated that there is a positive linear relationship between the deformation of the specimen and the pore-water pressure. In conclusion, it can be helpful to carry out work in cold regions safely by studying the variation of pore-water pressure and deformation characteristics of warm frozen soils under dynamic loading.