Subgrade structure suitable for water vapor migration prevention

The utility model discloses a subgrade structure suitable for water vapor migration prevention, which comprises a subgrade body, one side of the subgrade body is a filling side slope, the other side of the subgrade body is a digging side slope, the filling side slope and the digging side slope are respectively provided with a side slope drainage system and a side slope support structure, and eachside slope support structure comprises a concrete covering layer. Road shoulder drainage ditches are arranged on the two sides of the roadbed body respectively, a drainage pipeline is arranged below the road shoulder drainage ditches close to the excavation side slope and communicated with the road shoulder drainage ditches above the drainage pipeline through a water seepage pipeline, a water-resisting layer is arranged in the roadbed body, and the two side portions of the water-resisting layer are inclined downwards respectively. And two side edges of the water-resisting layer are respectively connected with a draina