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

Area of Science:

• Geotechnical Engineering
• Seismology
• Rock Mechanics

Background:

• Weak interlayers are critical factors in seismic rockslides, but their precise influence on slope response and damage remains unclear.
• Understanding these effects is crucial for seismic hazard assessment and slope stability design in earthquake-prone regions.

Purpose of the Study:

• To investigate the effect of weak interlayer thickness on the seismic response and dynamic behavior of rock slopes.
• To analyze topographic amplification, acceleration characteristics, and deformation patterns under seismic loading.

Main Methods:

• Series of shaking table tests were conducted on two model rock slopes with horizontal weak interlayers of varying thicknesses.
• Scaled Wenchuan earthquake ground motion was used to excite the slopes.
• Accelerometers measured seismic responses at different locations within the slopes; data were analyzed for amplification, acceleration, and deformation.

Main Results:

• Both slopes showed topographic amplification in the upper sections, with greater amplification differences between the slope face and interior in the model with a thinner interlayer.
• Structural deterioration and nonlinear responses were observed, including acceleration time lags, reduced resonant frequencies, and Fourier spectral ratios.
• Deformation patterns like crack development, settlement, and collapse were more severe in the slope with the thinner interlayer.

Conclusions:

• The thickness of the weak interlayer significantly influences seismic slope response and damage.
• Thicker weak interlayers exhibit an energy isolation effect, reducing overall slope deformation and damage.
• Thinner weak interlayers lead to more pronounced amplification and severe deformation, increasing landslide susceptibility.