Correlation between the excess cavity gas pressure and the dynamic response of a slope cavity under strong earthquake conditions

There are often some cavity structures in engineering slopes, such as early structural fracture cavities, dissolution fracture cavities, existing seismic fracture cavities, abandoned mines, etc. The excess pore gas pressure generated in engineering slopes with cavities under the action of sudden seismic loads, as well as the damage characteristics and mechanisms of the slope, the action laws of excess pore gas pressure, the mechanism of gas-rock interactions, and the triggering mechanism of seismic landslides, are all important research topics. This study, on the one hand, provides a valuable supplement to the theoretical foundation for understanding the deformation and failure mechanisms of slopes under seismic action; on the other hand, it provides a scientific basis for seismic slope stability evaluation and disaster prevention. In this study, a large-scale shaking table physical model test was designed for the slope with cavity. Under certain similar conditions, by inputting different seismic waves, the correlation between the excess cavity gas pressure and the dynamic response of the slope under strong earthquake conditions was systematically studied. The study found that: (1) Under the condition of low-intensity earthquake, there is almost no excess cavity gas pressure in the slope cavity, and the dynamic response of the slope has the same characteristics as that of the ordinary slope. (2) Under the condition of strong earthquake, the slope cavity will produce instantaneous excess cavity gas pressure, and the peak of air pressure will change with the change of cavity elevation, excitation intensity and excitation frequency. (3) Under the condition of strong earthquake, the peak value of acceleration response in the slope with cavity often appears after the peak pressure, which proves that the excess cavity gas pressure has a significant effect on the dynamic response of the slope.