Numerical study on mechanical characteristics of gabion mixed media with discrete element method

Gabion mixed media is an important ecological protection method for preventing riverbank scouring. It is favored by engineers for its use of local materials, low carbon footprint, and environmental friendliness. However, the mechanical characteristics of gabion mixed media are closely related to the shape of the gabion mesh, the diameter of the gabion wire, and the type of internal media. Thus, its macroscopic properties are difficult to analyze. Therefore, this study adopts a discrete element method, Particle Flow Code 3D (PFC3D), to establish a numerical calculation model of gabion structures. This method analyzes the mechanical characteristics of gabion structures filled with spherical and oblate stones by considering porosity, mesh shape, filler size, and mesh size. Key results demonstrate that the bearing capacity and stability of a gabion structure filled with oblate stones is stronger than that of a gabion structure filled with spherical stones, with an increase of about 25 % in bearing capacity. Porosity and mesh shape have a considerable effect on the compressive strength of the gabion structure. Compared with high-porosity gabion structures, low-porosity gabion structures have a 50 %-65 % increase in compressive strength. Additionally, hexagonal mesh gabion structures exhibit better stability than quadrilateral mesh gabion structures and under axial loads, the hexagonal mesh is less prone to breakage. Increasing mesh size may cause smaller fillers to overflow, reducing the porosity of gabion structures and resulting in decreased compressive strength. The results of this study can provide a basis for estimating integrated parameters of gabion mixed media and determining slope stability.