Wave propagations through jointed rock masses and their effects on the stability of slopes

• Wave propagation characteristics are discussed.
• Rock mass slope with discontinuity joints is modeled by FEM.
• A series of shaking table tests are conducted.
• Damage mechanism of rock slope with bedding discontinuity joints is clarified.

Seismic behavior in rock slopes with discontinuities is largely governed by the geometrical distribution and mechanical properties of the discontinuities. Particularly, high and steep rock slopes, which are dominated by bedding and toppling discontinuity joints, are likely to collapse and cause serious damage to structures near the slopes. Because the composition of geological materials and discontinuities becomes more complex, and depending on the specifics of the ground motion caused by the earthquake, slope stability becomes very complicated under earthquake loadings. Special attention should be paid to the study of wave propagation phenomena in rock masses and their effects on the stability of rock mass slopes. This research first focuses on the analysis of the wave propagation phenomenon using numerical methods. The wave propagation characteristics in rock mass slopes with bedding and toppling discontinuity joints are assessed using two-dimensional, dynamic FEM analyses. An analytical result is obtained in the time domain and allows one to consider multiple wave reflections between joints. Next, a series of shaking table tests are conducted on a scaled model of a high and steep rock slope with bedding discontinuity joints. The shaking table tests are performed to evaluate the influence of wave propagation on the stability of the slope. These tests show that an amplification area will form at the top of the slope. When the amplitude of the input acceleration reaches a certain value, an area at the top of the slope completely collapses along a slide surface, which is simulated using Teflon tape in the experiments.