Tunnel temporary isolating and blocking device and construction method for temporarily isolating and blocking tunnel

The invention provides a tunnel temporary isolating and blocking device and a construction method for temporarily isolating and blocking a tunnel, wherein the tunnel comprises a tunnel starting end communicated with the outside and a non-communicated tunnel tail end; the tunnel temporary isolating and blocking device comprises a bag body, a reserved pipe, pressurizing equipment and injection equipment, wherein the bag body is arranged between the tunnel starting end and the tunnel tail end and comprises a first side facing the tunnel starting end and a second side facing the tunnel tail end; a filling space is formed between the second side and the tunnel tail end and is used for accommodating seeped external soil and water; the reserved pipe is communicated from the first side to the second side; the pressurizing equipment is communicated and connected with the bag body and presses pressurizing media into the bag body so that the bag body expands and further jacks and supports the inner wall of the tunnel; and the injection equipment is communicated and connected with the reserved pipe and injects filling media into the filling space. The device and the method have the advantages that the goal of isolating and blocking the tunnel in the construction stage is achieved; external water and soil entering the tunnel can be effectively reduced; and the further diffusion of a dangerous case is further avoided.