Abstract: A method for water leakage prevention in a portion connecting a first pipeline to a second pipeline having one end thereof in communication with a portion of the first pipeline is provided. This method includes the steps of passing elastically deformable drawing means from the other end of the second pipeline to one end of the first pipeline; engaging an impermeable cut-off member, having an expandable hose portion and a flange portion provided integrally with one end of the hose portion, with the drawing means at one end of the first pipeline at the hose portion; drawing the cut-off member into the first and second pipelines by drawing back the hose portion of the drawing means toward the other end of the second pipeline; and disposing the cut-off member in the first and second pipelines, so that the flange portion is positioned within the first pipeline and the hose portion extends within the second pipeline.

Abstract: A cut-off material is provided, which includes an impermeable cutoff member (10, 70) provided with an expandable hose portion (18, 72) and a flange portion (20, 74) formed integrally with one end of the hose portion. The cutoff member is disposed in first and second pipelines, so that the flange portion is positioned within the first pipeline (12) and that the hose portion is positioned within the second pipeline (14). The cut-off member is maintained, for example, by a base (24,54,82) that is wound to be radially expandable, so that the flange portion is brought into liquid tight contact with the inner surface of the first pipeline and the hose portion extends within the second pipeline.

Abstract: A method for preventing water leakage into and out from a pipeline utilizes an injection material and a liner. The injection material exhibits fluidity and hardenability. The liner includes an elastically deformable sleeve having an outer diameter smaller than the inner diameter of the pipe and a plurality of elastically deformable and successively circumferentially extending projection portions formed at axial intervals on the circumferential surface of the sleeve; a sheetlike base placed inside the sleeve in a radially expandable, wound cylindrical form; fixing means for maintaining the base in a substantially cylindrical form when the base is radially expanded inside the sleeve; and check valve means defined by the sleeve and the base when the base is radially expanded. The check valve means permits the injection material to flow from the inside of the base into the space between the projection portions in the axial direction.