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Abstract: Cracking of early-age concrete can occur in the track beds of high-speed railways due to changes in material properties, environmental effects, and construction processes. This is a multi-field, time-varying issue involving hydro-thermo-chemo-mechanical coupling, but to date, research has not adequately described early-age cracking mechanisms in track beds, and few risk control measures have been proposed. To solve this problem, we incorporate the hydration degree of concrete into multi-field coupling equations for early-age concrete, and set boundary conditions that account for environmental influences and various stress factors which typically cause early creep of concrete. A four-field coupled risk prediction model is built on hydro-thermo-chemo-mechanical properties, and used to calculate and analyze various time-varying behaviors (including the risk and form of cracking) in the hydro, thermo, chemo, and mechanical fields of early-age concrete. Finally, we focus on material-related factors (maximum heat of hydration and peak heat release time), environmental factors (temperature difference between day and night, average daily cooling rate, and intensity of solar radiation), and construction technique factors (molding temperature, pouring time, and thermal insulation coefficient). The influence of these factors on the early-age cracking risk of the track bed is analyzed, and risk control measures against early cracking are proposed accordingly.