关键词: 冻胀, 动荷载, 冻土, 孔压, 动孔压模型

Abstract:   Pore water pressure in frozen soil is a key physical quantity for revealing the mechanism of frost heave and thaw settlement in cold regions. To systematically analyze the development pattern and influencing mechanism of pore pressure in frozen soil under dynamic loading, pore pressure in warm saturated frozen soil under dynamic loading was measured based on indoor dynamic triaxial tests. The effects of temperature, dynamic stress amplitude, and initial dry density on pore pressure were investigated. Based on this, a three-parameter pore pressure-vibration order empirical model considering the above factors was established, and the applicability of the model was verified. The results show that the development pattern of pore pressure in warm saturated frozen soil under dynamic loading is similar to that of thawed soil, and can be divided into three main stages: rapid increase, slow increase, and dynamic stabilization. Temperature has the most significant impact on pore pressure, especially at the test temperature of -0.5 ℃, where the rate of pore pressure change is the fastest, reaching a peak value of 265.24 kPa. The peak value of frozen soil pore pressure increases with increasing temperature and dynamic stress amplitude, and decreases with increasing dry density. In the early stage of loading, the pore pressure and strain of frozen soil show an approximately linear relationship. The established model has a good fitting effect (R2≥0.98) and can accurately predict the variation pattern of pore pressure in frozen soil under different test conditions.

Key words:  , frost heave, dynamic load, frozen soil, pore pressure, dynamic pore pressure model