High fill bottom drainage system and construction method

The invention discloses a high-fill bottom drainage system and a construction method, which comprises a main blind ditch, a secondary blind ditch and a branch blind ditch which are arranged according to the surface catchment area and flow rate, a gully with large catchment area and flow rate, a low-lying ditch which is provided with the main blind ditch along the main gully, and a small gully or the low-lying ditch which is provided with the secondary blind ditch, branch blind ditches should be arranged for spring water and seepage at exposed positions by combining the field terrain; the system further comprises a spring opening drainage structure and a horizontal drainage layer structure, the spring opening drainage structure is provided with spring opening blind ditches according to spring opening grouping to be connected with the main blind ditches, the horizontal drainage layer structure is arranged in a gravel pile or dynamic compaction replacement treatment area, and a horizontal drainage layer is arran