| 摘要 |
PROBLEM TO BE SOLVED: To provide a rot-preventing method for a mud adding material of a mud pressuring shield method, which rot-preventing method is easily usable, cheap, safe and having antiseptic effect and requires neither much cost up in a rot preventing practice nor much labor due to application of an antiseptic at each required time, and to provide a mud adding material having rot-preventing function and of a mud pressuring shield method. SOLUTION: Viscosity decrease is suppressed by proliferation of bacteria in the mud adding material by adding an additive comprising a magnesium salt to the additive for the mud pressuring shield method. Magnesium hydroxide is used as the magnesium salt. The additive is adjusted so that the magnesium hydroxide content in the mud adding material of the mud pressuring shield method is 0.5-20 wt.%. The rot is prevented by adding the additive to the mud adding material of the mud pressuring shield method. COPYRIGHT: (C)2007,JPO&INPIT |
