Assessing the Dynamic Strength of Slate Foliation: Shaking-Table Tests and DEM Implementation

Abstract

In this study, a sequence of experiments using a shaking table instrument was undertaken to explore the dynamic resilience of slate foliation, encompassing both unpenetrated and completely penetrated foliation conditions. Exploration was conducted into the impact of foliation's static friction angle, slope angle, and various frequencies on dynamic strength. Subsequently, analyses based on existing theories, Newmark’s method, and Malla’s method were performed to compare the test results. A dynamic strength criterion specific to foliation was proposed to predict the dynamic resistance of fully penetrated foliation. This criterion was then implemented based on the discrete-element method (DEM) for engineering practice. The findings revealed the following: (1) The dynamic mechanical strength of the nonpenetrated foliation exhibited high resistance to failure during the shaking-table test. (2) Fully penetrated foliation with a higher static friction angle yielded a higher critical acceleration. However, the critical acceleration decreased considerably when the slope angle and frequency of the dynamic loading increased. (3) Newmark’s method overestimated critical acceleration under high static friction angles while displaying an underestimation trend at lower friction angles. Conversely, Malla's method exhibited a more substantial disparity in critical acceleration estimation than Newmark. (4) This study introduced a model that incorporates the static friction angle, slope angle, and frequency as parameters to predict the critical acceleration of fully penetrated slate foliation reasonably. (5) The DEM analysis further confirmed that the proposed model accurately predicted the sliding failure behavior of foliation under both harmonic sine wave excitation and actual seismic events.