Effect of Particle Shape on the Load-Bearing Capacity of Pebble Aggregates

The arrester bed on a truck escape ramp is critical for ensuring vehicle safety in cases of brake failure by using the friction between tires and aggregate particles to slow the vehicle down. However, the diverse shapes and unpredictable distribution of these particles challenge traditional modeling and testing methods, affecting the accuracy of arrester bed load-bearing capacity assessments in such scenarios. This study presents an innovative approach for modeling diverse pebble shapes utilizing the discrete-element method (DEM) and leverages microparameter calibration techniques to replicate the physical behaviors of actual pebble particles with high precision, facilitating the creation of accurate three-dimensional models. Through meticulous calibration of essential microparameters, such as friction parameters via open-top box compression tests, this research ensures an exceptional correlation between the simulation models and actual conditions. Based on the built DEM model, this study provided detailed insights into the load-bearing characteristics of pebble aggregates under compression, emphasizing the distinct behavior of spherical, rod-shaped, and ellipsoidal particles from both macroscopic and microscopic perspectives. The compression analysis revealed distinct load-bearing patterns among particle shapes. During the steady growth phase, the downward movement of particles increased contact forces, particularly normal forces, with spherical particles generating the highest values due to their larger volume. In the rapid growth phase, continued descent led to amplified forces from reduced spacing and increased contact points. Spherical particles maintained a uniform force distribution. In contrast, rod-shaped particles exhibited limited movement and higher vertical force chains, whereas ellipsoidal particles showed intermediate behavior, resulting in varied force transmission and impacting overall structural stability. Insights gained from this study offer valuable contributions to the design and utilization.