Dynamic acceleration response of a rock slope with a horizontal weak interlayer in shaking table tests

Abstract

The weak interlayer in a rock slope often plays a significant role in seismic rockslides; however, the effect of weak interlayer on the seismic slope response and damage process is still not fully understood. This study presents a series of shaking test tests on two model slopes containing a horizontal weak interlayer with different thicknesses. A recorded Wenchuan earthquake ground motion was scaled to excite the slopes. Measurements from accelerometers embedded at different elevations of slope surface and slope interior were analyzed and compared. The effect of the weak interlayer thickness on the seismic response was highlighted by a comparative analysis of the two slopes in terms of topographic amplification, peak accelerations, and deformation characteristics as the input amplitude increased. It was found that the structure deterioration and nonlinear response of the slopes were manifested as a time lag of the horizontal accelerations in the upper slope relative to the lower slope and a reduction of resonant frequency and Fourier spectral ratio. Test results show that under horizontal acceleration, both slopes exhibited significant topographic amplification in the upper half, and the difference in amplification between slope face and slope interior was more pronounced in Slope B (with a thin weak interlayer) than in Slope A (with a thick weak interlayer). A four-phased dynamic response process of both slopes was observed. Similar deformation characteristics including development of strong response zone and macro-cracks, vertical settlement, horizontal extrusion and collapse in the upper half were observed in both slopes as the input amplitude increased; however, the deformations were more severe in Slope B than in Slope A, suggesting an energy isolation effect of the thick interlayer in Slope A.

Effects of Earthquake on Behavior Characteristics of Fault Gouge in Time-History Analysis of Slope

“…ey observed time lag because the slopes, which have the opposite directions, were differently applied with positive and negative directions of acceleration. Even Section 3 of this study, it is also confirmed that the time lag can occur depending on the amount of positive and negative acceleration in the seismic acceleration curve since the slope has only one direction (Figures 5(c) and 5(d)), and this result can be considered the same as the results of Liu et al [40].…”

“…In this section, the results of this study are compared with the results of previous studies, and application and limitation are mentioned. Liu et al [40] conducted a shaking table test for the two rock slopes, which have a weak layer and the opposite direction, and simulated this situation through 3D dynamic analysis. ey observed time lag because the slopes, which have the opposite directions, were differently applied with positive and negative directions of acceleration.…”

“…hanging wall) points of Figure 4 15). Regarding the topographical characteristics, it was reported not only that the upper part of the slope is more dangerous than the lower part [40] but also that the toe part of the slope is more dangerous because stress and displacement are concentrated [43]. It can be different depending on the distributions of the materials comprising the slope and the influence of adjacent structures.…”

Development of a Model Material for Dynamic Geotechnical Model Tests

“…Model testing involves scaling down a geological prototype according to the principle of similarity and then magnifying the physico-mechanical parameters of the model by observing the various physical phenomena of the model and using the same similarity principle to analyse the geological problems to be studied [23]. In the model test, it is difficult to realize complete similarity between prototype and model due to the limitations of test conditions, material preparation and other factors.…”

An empirical model for the travel distance prediction of deflection-type rock avalanches in the wenchuan earthquake area

“…Rock slides and collapses are the main types of earthquake disasters in LMS Orogenic Zone, and each strong earthquake usually causes massive rockslides and collapses in this region. For example, the tectonic uplift caused by the Wenchuan earthquake changed the slope gradient instantly (Li et al, 2014) and triggered more than 60,000 rock slides over an elliptical area of approximately 44,000 km 2 along the fault rupture zone (Liu et al, 2021b), which directly led to approximately 20,000 deaths.…”