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Frost-heaving characteristics and formation mechanism of saturated sandstone under unidirectional freezing conditions
Abstract In this study, a series of frost-heaving experiments were conducted on saturated sandstone at varying cooling rates under unidirectional freezing conditions. The frost-heaving strain in the freezing process was examined using a novel laboratory testing methodology. The results showed that the frost-heaving behavior of the saturated sandstone was significantly affected by the freezing direction and rate. Specifically, the rapid freezing of sandstone parallel to the freezing direction resulted in a more pronounced frost-heaving strain than that perpendicular to the freezing direction. The rock freezing rate had a positive correlation with the peak frost-heaving strain parallel to the freezing direction, and a negative correlation with that perpendicular to the freezing direction. A microstructure-based conceptual model is proposed to determine the frost-heaving pressure. The conceptual model showed that the ice pressure, determined by the pore-water pressure and capillary force, resulted from the crystallization of the pore water within the pore structure. A nonlinear relationship was observed between the ice pressure and crystallization rate. Capillary forces were more significant for slow crystallization processes, resulting in a larger difference between ice and water pressures. At high crystallization rates, the hydraulic pressure acted on the pore structure before the capillary forces become significant, leading to a smaller difference between the water and ice pressures. Rapid crystallization processes resulted in the uneven distribution of ice pressure within the pore structure, with subsequent re-equilibration occurring with the migration of unfrozen water. The proposed conceptual model presents a new perspective for obtaining an improved understanding of the microscopic frost-heaving mechanism involved in the freeze-thaw damage of porous rocks. It provides an evaluation method for the behavior of rocks during weathering by frost heave in cold regions.
Highlights A microstructure-based conceptual model is proposed to determine the frost-heaving pressure. Frost-heaving behaviors are directional under unidirectional freezing conditions. The magnitude of the frost-heaving pressure is affected by the crystallization rate and freezing direction. During the rapid crystallization, the ice undergoes melting and recrystallization in the microscopic pore structure.
Frost-heaving characteristics and formation mechanism of saturated sandstone under unidirectional freezing conditions
Abstract In this study, a series of frost-heaving experiments were conducted on saturated sandstone at varying cooling rates under unidirectional freezing conditions. The frost-heaving strain in the freezing process was examined using a novel laboratory testing methodology. The results showed that the frost-heaving behavior of the saturated sandstone was significantly affected by the freezing direction and rate. Specifically, the rapid freezing of sandstone parallel to the freezing direction resulted in a more pronounced frost-heaving strain than that perpendicular to the freezing direction. The rock freezing rate had a positive correlation with the peak frost-heaving strain parallel to the freezing direction, and a negative correlation with that perpendicular to the freezing direction. A microstructure-based conceptual model is proposed to determine the frost-heaving pressure. The conceptual model showed that the ice pressure, determined by the pore-water pressure and capillary force, resulted from the crystallization of the pore water within the pore structure. A nonlinear relationship was observed between the ice pressure and crystallization rate. Capillary forces were more significant for slow crystallization processes, resulting in a larger difference between ice and water pressures. At high crystallization rates, the hydraulic pressure acted on the pore structure before the capillary forces become significant, leading to a smaller difference between the water and ice pressures. Rapid crystallization processes resulted in the uneven distribution of ice pressure within the pore structure, with subsequent re-equilibration occurring with the migration of unfrozen water. The proposed conceptual model presents a new perspective for obtaining an improved understanding of the microscopic frost-heaving mechanism involved in the freeze-thaw damage of porous rocks. It provides an evaluation method for the behavior of rocks during weathering by frost heave in cold regions.
Highlights A microstructure-based conceptual model is proposed to determine the frost-heaving pressure. Frost-heaving behaviors are directional under unidirectional freezing conditions. The magnitude of the frost-heaving pressure is affected by the crystallization rate and freezing direction. During the rapid crystallization, the ice undergoes melting and recrystallization in the microscopic pore structure.
Frost-heaving characteristics and formation mechanism of saturated sandstone under unidirectional freezing conditions
Niu, Shuaishuai (author) / Luo, Xuedong (author) / Jiang, Nan (author)
2023-10-17
Article (Journal)
Electronic Resource
English
Ground Freezing and Frost Heaving
| NTIS | 1962
Empirical Frost Heave Model for Saturated Rock Under Uniform and Unidirectional Freezing Conditions
| Online Contents | 2018