Finite Element Analysis of Irrigation Channel Embankment Slope Stability Under Traffic Loading

The stability of road embankments situated along irrigation channels presents a recurrent geotechnical challenge in agricultural regions, where hydrostatic pressures from fluctuating channel water levels, groundwater conditions, and vehicular traffic act in combination on the embankment structure. This paper reports a systematic numerical investigation into the stress state and deformation behavior of channel outer-curve embankments subjected to static traffic loads, conducted using the Plaxis 2D finite element program with the Mohr–Coulomb constitutive model and the phi-c reduction technique for factor of safety (F.S.) determination. The study encompasses forty-eight geometrically and materially distinct slope configurations, covering dense, medium, and loose sand embankments (slope angle α = 45°) and stiff, medium, and soft clay embankments (α = 55°), under four hydraulic boundary scenarios ranging from dry–full supply level (Case 1) to saturated–rapid drawdown (Case 4), with traffic loads of 30 kN/m2 and 60 kN/m2 representing equivalent axle load intensities. It is acknowledged that the plane-strain idealization adopted herein represents a conservative simplification of the true three-dimensional curved geometry; this limitation and its implications are discussed in the methodology. Total displacements ranged from 0.187 m to 0.264 m for sand embankments and from 0.145 m to 0.760 m for clay embankments, with soft clay under Case 1 producing displacements approximately seven times those of remaining hydraulic cases, attributable to the concentrated lateral water pressure differential acting on the inner slope face. Sand embankment F.S. values spanned 0.99 to 1.12, with loose sand under full traffic load approaching the threshold of instability. Clay F.S. values ranged from 1.80 to 3.85, with stiff clay under the lightest hydraulic loading representing the most stable configuration. The study provides practical guidance for the design and assessment of channel embankments under concurrent hydraulic and traffic loading conditions.