Tunnel external thermal insulation directly-buried underground pipe

The utility model discloses a tunnel hole external thermal insulation directly-buried underground pipe which comprises a working pipe, an outer protective pipe is wrapped outside the working pipe, anda thermal insulation layer is filled between the outer protective pipe and the working pipe. The inner side and the outer side of the working pipe are coated with an inner anti-corrosion layer and anouter anti-corrosion layer respectively. The heat preservation directly-buried concealed pipe is arranged on the concrete base and provided with a soil and stone backfill layer. According to the utility model, the heat loss of drainage in the pipe can be effectively reduced, so that the drainage in the pipe can be guided and drained at a long distance and a small slope without freezing injury. Meanwhile, the heat preservation layer and the directly-buried pipe are combined into a whole, industrialized production is achieved, product quality and heat preservation performance are easy to guarantee, construction is easy