Shield tunnel first negative ring duct piece backward-pushing-free rapid assembling and propelling device and method

The invention relates to the technical field of shield construction, and discloses a back-pushing-free rapid assembling and propelling device and method for a shield tunnel first negative ring duct piece. The technical problems that in the prior art, under the condition that the rear portion of a first negative ring duct piece is not supported, a shield tail is pushed out backwards in an empty mode, a shield cannot be pushed forwards in time for launching, and ring duct pieces are out of roundness, sink and are damaged due to the fact that the ring duct pieces are not supported or locally stressed too large are solved. The device is connected with a shield main machine, is propelled on a launching guide table, and comprises a propelling oil cylinder, a supporting steel pipe and a launching counter-force facility, the thrust oil cylinder is connected with the shield tail of the shield main machine; the supporting steel pipe cantilever is connected with a starting counter-force facility, and the supporting stee