Abstract: A method of rehabilitating underground pipes which comprises the steps of: (a) forming a liner pipe (5) by winding a strip (4) made of a synthetic resin into a helical shape so that the side edges of the convolutions of the wound strip (4) are interengaged with each other; (b) continuously introducing the liner pipe (5) into an underground pipe (1) while the liner pipe (5) is being advanced inside the underground pipe (1); inserting a slip restraining member in the form of a wire rod (6) continuously to the interconnected edges of the convolutions of the said strip (4), and then removing the said strip (4) when the diameter of said liner pipe (5) is to be increased at the same rate as said strip (4) for forming said helical liner pipe (5) is conveyed.

Abstract: This invention relates to a method of drilling apertures for branch lines (A) blocked by renovation lining of a main pipeline (B) which comprises setting a water plug (1) in the opening of each branch line (A) prior to lining, said water plug (1) carrying a position marker (14) comprising an antenna coil and a resonator adapted to be excited by a driving signal and, after stoppage of the driving signal, release a resonance signal remaining in the resonator from the antenna coil and said position marker being situated in a position which, upon setting of the water plug (1) in position, is substantially concentric with the axis of the branch line (A), causing an antenna assembly for detecting the resonance signal to travel within the main pipeline (B) to detect the position of the marker (14) and driving a drilling means (24) using the thus-detected marker position as a target from within the main pipeline.