Fracture properties of sandstone degradation under the action of drying–wetting cycles in acid and alkaline environments

Abstract

In order to study the fracture properties of sandstone degradation under the action of drying–wetting cycles in acid and alkali environments, laboratory tests were conducted on the sandstone specimens for 1, 3, 6, and 10 drying–wetting cycles in neutral (pH = 7), acid (pH = 4), and alkali (pH = 9) environments, respectively. The semi-circular bend (SCB) specimens were selected for mode I fracture testing, and the Brazilian splitting specimens were adopted to measure the tensile strength of sandstone. The results show that the acid and alkaline environments have a great effect on the fracture properties of sandstone degradation that is the largest one in the acidic environment (pH = 4), followed by that in the alkaline environment (pH = 9) and that in the neutral environment (pH = 7). The degradation of tensile strength of the sandstone is less than that of fracture toughness, and the relationships between mode I fracture toughness and tensile strength of sandstone are linear after soaking in acid and alkali environments.