In this paper, the slit Hopkinson pressure bar (SHPB) experiments were conducted to investigate the dynamic mechanical characteristics of red sandstone during acid dry-wet cycles. The appearance of the samples was evaluated using scanning electron microscopy, and the process of red sandstone degradation under acid dry-wet cycles was examined. The results reveal that, as compared to neutral solution, acid solution enhances the degree of degradation induced by dry-wet cycles in red sandstone. The dynamic compressive strength and elastic modulus of red sandstone steadily decline as the number of dry-wet cycles increases, and the lower the pH of solution, the greater the reduction. The mechanism of degradation of red sandstone during acid dry-wet cycles may be explained in two ways. First, the chemical interaction between the mineral components in the sample, such as cement and feldspar, and H⁺ in the acid solution has accelerated the formation of secondary pores and fractures, resulting in a decrease in the cementation capacity between mineral particles. Second, partial breakdown of the major mineral particles softens the mineral skeleton.

Studying the dynamic properties of rocks in complex environments is of great significance to the sustainable development of deep-sea metal mineral resource extraction. To investigate the influence of dry–wet cycles on the dynamic tensile properties and energy dissipation of red sandstone, a series of dynamic Brazilian disc tests was carried out through the split Hopkinson pressure bar (SHPB) apparatus. The dynamic tensile behaviors and energy dissipation distribution of the red sandstone specimens after different dry–wet cycles (0, 10, 20, 30 and 40 cycles) were analyzed in this study. The degree of dynamic tensile fragmentation and energy dissipation of red sandstone is significantly affected by the loading rate. Specifically, when the number of dry–wet cycles remains constant, an increase in loading rate results in a significant reduction in the average fragment size, while the energy consumption density exhibits an approximately linear increase. At a fixed loading rate, the energy consumption density decreases approximately linearly with the increase in dry–wet cycles, and the higher the loading rate, the more sensitive the energy consumption density is to the dry–wet cycle. Under a fixed number of dry–wet cycles, the dynamic tensile strength has an exponential relation with the increase in energy consumption density.

The phenomenon of the drying-wetting cycle is a component of the weathering process and has a significant impact on the characteristics of rock materials. In order to examine the physical and dynamic tensile properties of red sandstone subjected to drying-wetting cycles, physical tests and dynamic splitting tensile tests were performed on red sandstone specimens under varying drying-wetting conditions. First, the split Hopkins pressure bar was used to perform dynamic tensile tests on red sandstone samples after varying numbers of drying-wetting cycles (0, 20, 40, 60, and 80). Second, the effects of the loading rate and drying-wetting cycles on dynamic tensile strength and energy dissipation of red sandstone were studied. Finally, taking into account the effect of the loading rate, a model was developed to predict the trend of decay in the dynamic tensile strength of red sandstone following drying-wetting cycles. The findings indicate that as the number of drying-wetting cycles increases, there is a decrease in longitudinal wave velocity and a marked degradation of the red sandstone due to the effects of the drying-wetting cycles. The dynamic tensile strength and dissipation energy density of red sandstone samples increase with the increasing loading rate. Under consistent loading rate conditions, the dynamic tensile strength and dissipative energy density of red sandstone samples exhibit a decrease as the number of drying-wetting cycles increases.