Laboratory investigation of the mode-I fracture of sandstone caused by a combination of freeze-thaw cycles and chemical solutions

The mechanical parameters and deterioration mechanisms of sandstone specimens obtained from the hydrofluctuation belt in the Three Gorges Reservoir Region of China were investigated under a combination of freeze-thaw cycles and different chemical solutions. The degradation in several mechanical characteristics was discussed, and the degree of freeze-thaw deterioration of the mechanical behaviors was quantitatively analyzed based on the crack propagation radii and a damage variable that reflects the changes in porosity. The results showed that the mechanical parameters of sandstone had a significant damage deteriorating trend under freeze-thaw cycles and different chemical solutions. And the degree of damage deterioration of fracture toughnessK(IC)was the greatest, followed by that of tensile strength; that of compression strength was the smallest. There was obvious consistency among fracture toughnessK(IC), tensile strength, and compression strength of sandstone under a combination of freeze-thaw cycles and different chemical solutions; those were obvious linear relationship. The crack propagation radii for the various effects of freeze-thaw cycles and chemical solutions were smaller than those of the natural state and the radii generally decreased with increasing freeze-thaw cycles.