MUD LEAKAGE INHIBITOR

PURPOSE:To provide a mud leakage inhibitor having improved workability and mud leakage inhibiting performance, consisting of a water-insoluble, water- absorbing resin, an org. treated clay and an inert org. liquid. CONSTITUTION:5-60wt% water-insoluble, water-absorbing resin (A) (e.g. a hydrolyzate of a starch/acrylonitrile copolymer), 0.5-5wt% org. treated clay (B) obtd. by subjecting smectites clay and a quaternary ammonium salt to an ion exchange reaction, and 35-94.5wt% inert org. liquid (C) (e.g. polyethylene glycol) which is a liquid at a temp. of -10-50 deg.C, neither swells nor dissolves component A and is non-reactive with component A, are mixed together to obtain a mud leakage inhibitor. The mud leakage inhibitor is slurried with stirring and introduced through the emergency inlet of a shield machine into the mixing chamber thereof under pressure and then into soil to be treated.