| 摘要 |
PURPOSE:To provide a lubricant compsn. for shield propulsion work with an enhanced fluidity, gel-strength, and water-absorbing and swelling capacity after being filled as well as applicability as a backfill by forming essential component of such compsn. from aq. dispersion of high water absorbent hydrogel compounded with minerals, surfactant, oil, etc. if necessary. CONSTITUTION:Aq. suspension is formed from (a) a highly water absorbing hydrogel which swells to several to several hundred times its original volume but is not sol. in water, such as partial hydrolysis proudcts of graft copolymer of starch- acrylonitrile or starch-methacrylate, which is added with as required (b) minerals such as clay or bentonite, (c) org. paste material such as sodium carboxymethylcellulose, starch, etc. (d) surfactant such as alkyl sulfate, polyoxyethylene alkylether, and (e) oils such as mineral oil, vegetable oil. The formed aq. suspension provides a lubricant compsn. for shield propulsion work which is used to reduce the propulsion resistance by being injected between the holed wall and the pipe body after shield propulsion and also has a function as a backfill. |
