Research on the Energy Dissipation Characteristics and Stress Wave Spectrum Analysis of Red Sandstone Subjected to Progressive Load Cyclic Impact

The damage accumulation and strength deterioration within rock masses due to frequent disturbance loads is a significant concern in the fields of rock mass engineering and deep mining. This study employed the ultrasonic detection system and the Hopkinson pressure bar test device to conduct cyclic impact tests on sandstone, aiming to unveil the energy evolution patterns and strain rate effect in sandstone under cyclic impact. The investigation focused on studying the characteristics of the stress wave spectrum during cyclic impact, as well as revealing anomalies in the stress wave spectrum resulting from progressive load cyclic impact. Additionally, a cumulative damage constitutive model of cyclic impact based on ultrasonic wave velocity was established. The results indicate the P-WR initially shows two forms: a slight increase followed by a subsequent monotonic decrease, and a monotonic decrease throughout. The e(d) shows two trends: a slight increase in the initial stage followed by a decrease oscillation, and a slight rise in the early stage followed by a subsequent monotonic or direct decrease. The spectrum of reflected wave and transmission wave exhibit an initial increase followed by a decrease, with the peak frequency typically ranging from 1000 to 3000 Hz. Under constant load cyclic impact, the number of impacts enhances the spectrum peak of the reflected wave while weakening that of the transmission wave. Under progressive load cyclic impact, both the reflected wave and transmission wave show a gradual upward trend for their respective spectrum peaks, but with different rates of increase.