Underground surrounding rock engineering displays unique mechanical properties after being subjected to disturbance loads. In this study, the self-developed CX-8568 impact-disturbance surrounding rock test system was utilized to conduct dynamic tests on gypsum specimens subjected to different lateral pressures. The results show that the presence of lateral pressure enhances the specimen’s ability to withstand disturbance loads, which shows higher lateral pressure results in a greater number of disturbance cycles required for specimen failure. Lateral pressure inhibits both the transverse and axial deformation of the specimen, leading to an increase in the elastic modulus and average cyclic disturbance times as lateral pressure rises. When the lateral pressure is held constant, the residual plastic strain of the specimen increases continuously with the number of cyclic disturbance cycles, while the elastic modulus of the specimen decreases steadily as the cyclic disturbance cycles increase. The application of disturbance loads causes significant spalling and damage to the free surface of the specimen under varying lateral pressures. At low lateral pressures, the specimen primarily experiences tensile splitting, whereas at high lateral pressures, shear failure occurs at the ends of the specimen, while tensile failure is observed in the middle. Through this study, we can more clearly understand the mechanical properties and failure characteristics of rock under disturbed load and provide theoretical guidance for the stability of rock engineering.

To analyze the characteristics of acoustic emission (AE) and electromagnetic radiation (EMR) signals in specimens with different water contents during impact loading, impact tests were conducted on sandstone under dry, natural, and saturated conditions using the split Hopkinson pressure bar (SHPB) system. The results show that water reduces the dynamic compressive strength and elastic modulus of sandstone, changes the failure mode from tensile failure to tensile-shear failure, and increases the amount of small-sized fragments after failure. AE and EMR signals effectively reflect the entire deformation process of specimens with different water contents under impact loading. In the elastic stage, only EMR signals appear, indicating that EMR is more sensitive to crack generation. In the yield stage, the AE signal count and energy increase sharply, indicating that the response to specimen failure is better. By comparing AE and EMR signals at different stages, it was found that water inhibits both the propagation and energy of AE and EMR signals. The damage factor D, quantified by AE and EMR counts, accurately represents the damage suffered by specimens with different water contents during impact loading. This study significantly advances the understanding of failure mechanisms in specimens with varying water contents and contributes to practical engineering monitoring of water-bearing rock mass stability.