Tunnel maintenance spraying trolley with variable section

The tunnel maintenance spraying trolley with the variable section comprises a truss assembly and waterproof tarpaulin, walking devices are installed at the bottoms of the two sides of the truss assembly, and a water tank is installed on the truss assembly; the waterproof tarpaulin is supported and covered on the truss assembly; a water collecting tank is mounted on the truss assembly through a water collecting tank bracket; the water collecting tank is connected with the water tank through a recycling water pumping pipe and a recycling water pump; a longitudinal water pipe is installed on the top of the middle of the truss assembly through a telescopic supporting rod and a support in a supporting mode and connected with a water tank through a water pumping pipe and a spraying water pump, a plurality of transverse water pipes are connected to the two sides of the longitudinal water pipe at intervals, and each transverse water pipe is connected with a spraying water pipe through a universal water pipe connectin