Abstract: High embankment fills constructed on river-terrace landforms often exhibit complex deformation mechanisms, and existing stability-control measures are frequently insufficiently targeted. This study examines a representative 40 m-high embankment section along the Nayong-Qinglong Expressway in Guizhou Province, employing an integrated approach combining multi-point field displacement monitoring with finite-element numerical simulation. The evolution of post-construction settlement and deep horizontal displacement is systematically analyzed. Layered settlement measurements are used to back-calculate the components of total settlement, and overall stability is evaluated using the strength-reduction method, with particular emphasis on identifying zones of concentrated deformation and their governing mechanisms. Results indicate that embankment compression is the predominant contributor to total settlement, accounting for approximately 61.2%, whereas foundation consolidation settlement primarily originates from the 3～5 m thick gravelly soil cover. Deep horizontal displacement is concentrated within two critical zones: the 0～2.5 m fill-gravel interface beneath the first berm, and the 6 m toe-retaining-wall influence zone beneath the third berm. Both zones correspond closely with the equivalent plastic regions identified in numerical analyses. The computed overall stability factor of safety is 1.35, suggesting a limited safety margin. Numerical simulation results exhibit good agreement with field monitoring data, with relative discrepancies maintained within 15%, thereby validating the reliability of the model. Based on these findings, a targeted suite of stability-control measures is proposed, including bidirectional geogrid reinforcement, anti-slide piles, deep drainage holes, and slope interception ditches, supplemented by a three-level dynamic early-warning mechanism.

Key words: High-Fill Embankment, Field Monitoring, Numerical Simulation, Factor of Safety, Stability Control, Settlement Patterns, Horizontal Displacement, Riverine Floodplain Landforms