Maintainable-type tunnel drainage system

The utility model discloses a maintainable-type tunnel drainage system which comprises a deeply-buried ditch, an annular drainage blind pipe, a longitudinal drainage blind pipe and an inspection well arranged on a tunnel side wall portion. The deeply-buried ditch, the annular drainage blind pipe and the longitudinal drainage blind pipe are arranged in the middle of the tunnel road surface, the inspection well comprises a vertical well shaft and a sealing door arranged on the vertical well shaft, the deeply-buried ditch and the vertical well shaft are communicated through a traverse grit basin, and a dredging device is arranged in each of the annular drainage blind pipe and the longitudinal drainage blind pipe and comprises a steel stranded wire and bristles fixed on the steel stranded wire. The inspection well is arranged on the tunnel side wall portion, so that road surface structure cannot be damaged, occupation of lanes and blockage of the lanes when the deeply-buried ditch is maintained can be avoided, and safety of maintaining personnel during working can be guaranteed; the longitudinal drainage blind pipe and the annular drainage blind pipe can be dredged by pulling the bristles on the steel stranded wires to remove sediment in the pipes, and bending and deforming of the blind pipes cause little influence on the cleaning process, so that anti-blocking effect is good.