Abstract: To identify the key controlling factors influencing the deflection of high-speed railway embankment under adjacent surcharge loads, a numerical simulation model was developed. Seven potential factors were considered for the investigation: namely, the compression modulus of the overlying stratum; the thickness of the overlying stratum (specifically in the reinforcement zone); the compression modulus of the underlying unreinforced stratum; the intensity of foundation soil treatment; as well as parameters related to surcharge load including its distance, width, and height. An analysis was conducted to delineate these influencing factors on the embankment deflections. The results indicate that for horizontal displacement of the track, the significance order of influencing factors is as follows: compression modulus of underlying stratum > distance from surcharge load > compression modulus of overlying stratum > thickness of overlying stratum > intensity of foundation soil treatment > height of surcharge load > width of surcharge load. For the vertical displacement, this order changes slightly but remains consistent with: compression modulus of underlying stratum > height of surcharge load > distance from surcharge load > width of surcharge load > thickness of overlying stratum > intensity of foundation soil treatment > compression modulus of overlying stratum. Notably, the significance order for the vertical displacement in the embankment closely mirrors that observed for the vertical displacement in tracks. When conducting the design of surcharge loading, it is essential to pay attention to controlling the spacing, height, and width of surcharge loading. Additionally, while selecting a reasonable soil treatment method and treatment depth. Attention should be given to the physical and mechanical properties of the soil in the project area.

Key words: High-Speed Railway Subgrade, Adjacent Surcharge Load, Influencing Factors, Width of the Surcharge Load, Compressive Modulus