The disaster mechanism of stress waves and the damage constitutive model of deep tight sandstone under shock and impact loads

The failure degradation of deep tight sandstone and the propagation attenuation properties of stress waves under disturbance loads are crucial for the safe and efficient exploitation of deep resources and the construction of underground engineering. This study conducts dynamic disturbance tests on sandstone under shock and impact loads. The differences in energy characteristics, and stress wave propagation of the samples are investigated. Additionally, the strain transformation and energy dissipation laws of the samples are analyzed. The attenuation characteristics of stress waves in the time and frequency domains are explored, and the correlations and distinctions in disaster mechanisms are further elucidated. Finally, a simplified yet effective damage constitutive model is established. The results indicate that the dynamic strength of the specimens exhibits a linear increase under both shock and impact loads, with growth rates of 30.55 and 42.90, respectively. For shock load, the linear growth rates of εm, εf, and εcr are 0.16%, 0.144%, and 1.99%, respectively, while under impact load, these growth rates are 0.112%, 0.150%, and 6.65%, respectively. The maximum storage energy growth rates under shock and impact loads are 0.48 and 0.42, while the dissipated energy growth rates are 0.43 and 0.46, respectively. The Qseismic decreases linearly at a rate of 0.26 under shock load and exhibits a class-exponential decrease under impact load. Additionally, the reflected and transmission waves display differential growth trends in both the time and frequency domains. Impact loads enhance the reflection intensity of the stress wave in both domains while diminishing its transmission intensity.