DEM modeling of polyhedral gravel particles and their mechanical response in runway applications

Gravel is a critical material in runway and road construction, where particle-scale behavior governs structural performance and durability. This study uses a concave polyhedral discrete element method (DEM) with laser-scanned particle geometries and an energy-conserving contact algorithm to capture realistic interactions. Contact parameters were calibrated through a combined response surface methodology and uniform design method, linking angle of repose and direct shear responses to six key mechanical factors. The optimized parameters enabled DEM results to agree well with regression models and experimental results, validating the calibration framework. Using these parameters, DEM simulations of gravel runways under aircraft loading were performed at horizontal velocities of 40–70 m/s and vertical sinking velocities of 0.3–1.2 m/s. Results show vertical settlement with surface indentations up to 40 mm. Runway deformation increases linearly with sinking velocity but decreases with a power law of horizontal velocity. These results demonstrate the reliability of polyhedral DEM in reproducing gravel mechanics and provide quantitative insights into the design and assessment of gravel runways.