Tunnel drainage system cleaning device and method and cleaning hemisphere structure design method

The invention discloses a tunnel drainage system cleaning device and method and a cleaning hemisphere structure design method, the tunnel drainage system cleaning device comprises a cleaning pipe, the cleaning pipe comprises a liquid injection pipe, the peripheral side of the liquid injection pipe is communicated with a telescopic pipe, and the end, away from the liquid injection pipe, of the telescopic pipe is in threaded connection with a cleaning hemisphere. The cleaning hemisphere comprises a shell-shaped cylindrical section and a hemisphere section, a V-shaped groove is formed in the end of the hemisphere section, an inverted filter layer is arranged in the V-shaped groove, and a nozzle cover is further arranged on the hemisphere section. The liquid injection pipe is formed by splicing a plurality of pipe joints. The device is suitable for circular pipelines of various diameters of a tunnel drainage system, meanwhile, long-distance pipeline washing and cleaning can be achieved, the tunnel maintenance eff