Under dynamic loads, such as blasting, excavation, or quarrying, rocks with fissures are the first to sustain damage, leading to instability in the engineering rock mass. To investigate the kinetic properties of fractured rocks, fractured coal mine sandstone specimens underwent impact compression tests using a dynamic–static combination SHPB (split Hopkinson pressure bar) test device at different loading rates under combined dynamic and static conditions. The damage characteristics of the specimens were analyzed from an energy point of view. The results show that under the dynamic and static combined condition, when five impact loading air pressures are used for loading at different impact rates, the trends of the dynamic stress–strain curves of prefabricated fissured rock samples under various impact pressures were discovered to be similar and were mainly categorized into three main stages of elasticity, yield, and destruction; the specimen’s dynamic compressive strength increases according to a power function relationship; as the average strain rate increases, the dynamic strain increases linearly and the dynamic modulus of elasticity increases in a quadratic relationship, all of which show a significant strain rate effect. The incident energy is a power function of the loading rate. The reflected, transmitted, and absorbed energies by the sample increase with the incident energy. The degree of the sandstone specimen fragmentation gradually grows with increasing impact loading rate and incident energy, as evidenced by a decrease in the scale of the fragments. The absorbed energy in the sample is mainly used for the deformation damage of the rock, and the more intense the fragmentation of the specimen, the more absorbed energy is required.

In order to analyze the effect of different corrosion times on the dynamic compression mechanical properties of sandstone, the coal mine sandstone specimens are subjected to corrosion in NaOH solution with pH 11 for 0 d, 1 d, 3 d, 7 d, 14 d, and 28 d, and then, the impact compression tests and Brazilian splitting test are conducted using a split Hopkinson pressure bar apparatus. The study results show that sandstone specimen mass and the average density growth rate increases, with the corrosion time first rapidly increasing and then tending to level off the trend. The impact of the compression specimens on the dynamic stress–strain curve change law is basically the same, but the time gradient curve shape is different, and the line elastic deformation stage and plastic deformation stage curve difference gradually decreases. The specimen dynamic compressive strength and the dynamic elastic modulus with corrosion time are quadratic, and the exponential function declines the relationship. After corrosion of 28 d sandstone specimens, the dynamic compressive strength and dynamic elastic modulus are much lower than the uncorroded specimens. The average strain rate and the dynamic peak strain with the corrosion time extension are a quadratic function of the increasing relationship after the corrosion effect of the sandstone dynamic peak strain, and the average strain rate is significantly greater than the uncorroded specimens. With the corrosion time extension of sandstone specimens by the impact of damage degree being increased, the 14 d and 28 d specimen ruptures’ degree is much greater than other time gradients. The dynamic tensile strength of the split specimens decreases with increasing corrosion time; the dynamic peak strain increases quadratically; and the transmitted energy also decreases with increasing corrosion time.

The aim of this study was to examine the effects of sandstone ring specimens with different inner diameters on dynamic compression mechanical characteristics after dry and wet circulation. To carry out our study, we subjected a sandstone ring specimen with a 50 mm outer diameter and a 0~25 mm inner diameter to 10 cycles of dry and wet circulation. Afterward, we recorded the specimen’s basic physical parameters and used a split-Hopkinson pressure bar (SHPB) test device to perform an impact compression test. Following dry and wet circulation, our results showed that the mass loss rate increased and the volume expansion rates and density decreased with the increase in the inner diameter of the sandstone ring sample. Simultaneously, with the increase in the inner diameter of the specimen ring, the dynamic compressive strength of the specimen presented an exponential negative correlation, the dynamic elastic modulus presented a quadratic negative correlation, and the dynamic peak strain presented a quadratic positive correlation. Concurrently, the average particle size of the specimen decreased, and the degree of breakage increased with the increase in the sandstone sample’s inner diameter. Regarding the energy analysis performed in this study, the sandstone ring sample’s energy dissipation increased, and its kinetic performance evidently weakened with the increase in the ring sample’s inner diameter. The results of this study have certain reference values for the construction and maintenance of natural cavity rock and underground hard rock roadways.

In order to study the dynamic properties of temperature–water-coupled sandstone under axial pressure, impact compression tests were carried out on sandstone samples after temperature–water coupling under eight types of axial pressure (0.5~4.0 MPa) loading as well as no axial pressure loading by using the split-Hopkinson pressure bar (SHPB) test set. The results showed that the mass, volume, and density of the sandstone specimens increased by 0.57%, 0.37%, and 0.20%, respectively, after temperature–water coupling. With increasing axial pressure, the dynamic compressive strength of temperature–water-coupled sandstone samples decreased as a linear function, the dynamic strain increased as a quadratic function, the dynamic modulus of elasticity decreased as a quadratic function, and the average strain rate increased as an exponential function, indicating a strong strain rate effect. From the energy point of view, as the axial pressure increases, the absorption energy of the sample increases, the reflection energy gradually decreases, the crushing degree of the sample increases, and the size of the broken pieces decreases; the average particle size of the sandstone sample pieces decreases quadratically with the increase in the absorption energy and linearly with the increase in the axial pressure.