A series of compression experiments was conducted to observe the pore-water pressure variations of saturated warm frozen soils over time. The results indicate that saturated warm frozen soils can exhibit excess pore-water pressure when subjected to external loads. The pore-water pressure fluctuates rather than varying monotonically, and it gradually increases with increasing compressive deformation as the pores are compressed. Furthermore, the permeability of the soil allows pressure dissipation. Thus, the pore-water pressure is continuously changing because of the interactions between these two opposing processes. The peak pore-water pressure follows an exponential relationship with the soil temperature and decreases to a steady value as the temperature decreases. A dissipation trend is observed after the peak pressure is reached. This trend reflects the influence of consolidation in the deformation of warm frozen soils. As the temperature increases, the role of the consolidation becomes more significant.

The foundation of constructions built in the permafrost areas undergo considerable creeping or thawing deformation because of the underlying ice-rich permafrost. Soil improvement may be of advantage in treating ice-rich permafrost at shallow depth. Sulphoaluminate cement was a potential material to improve frozen soil. Simultaneously, two other cements, ordinary Portland cement and Magnesium phosphate cement were selected as the comparison. The mechanical behavior of modified frozen soil was studied with thaw compression tests and unconfined compression strength tests. Meanwhile, the microscopic mechanism was explored by field emission scanning electron microscopy, particle size analysis and X-ray diffractometry. The results showed Sulphoaluminate cement was useful in reducing the thaw compression deformation and in enhancing the strength of the frozen soil. The improvement of the mechanical behavior depended mainly on two aspects: the formation of structural mineral crystals and the agglomeration of soil particles. The two main factors contributed to the improvement of mechanical properties simultaneously. The thicker AFt crystals result in a higher strength and AFt plays an important role in improving the mechanical properties of frozen soils.The study verified that Sulphoaluminate cement was an excellent stabilizer to improve ice-rich frozen soils.