Water conveyance tunnel with prestressed composite lining for shield tunnelling

The invention provides a water conveyance tunnel with a prestressed composite lining for shield tunnelling. The tunnel comprises an ordinary reinforced concrete outer lining (1) which is formed by shield construction and is an assembled segment ring, wherein segments on the same ring are connected by connecting bolts (2); dowel bars (3) are installed in hand holes on the assembled segment ring; concrete is directly poured on the outer lining (1) to form an inner lining (5); shear keys (6) are formed in such a manner that concrete is filled in the hand holes of the outer lining; and the inner lining (5) and the outer lining (1) are combined via the dowel bars (3) and the concrete shear keys (6) to form a composite lining structure. Thus, the defects of great construction difficulty, long construction period and higher investment caused by the separated pressure pipeline water conveyance scheme for shield tunnelling are overcome. The technical problems of high head, high flow, high load and possibility of endangering the tunnel safety due to seepage of underground water, which are encountered when the soft soil layer of the riverbed is tunnelled in the shield tunnelling construction of the Yellow River crossing tunnel, are solved. Besides, the invention reduces the project investment and has obvious social benefits.