| 摘要 |
<p>PURPOSE:To provide an additive for the shield driving method which can give excellent pressure transfer characteristics, plastic flow properties, working face stabilization effect, water stop effect, etc., to dug earth and sand by using a coal ash slurry or a composition containing the same. CONSTITUTION:The title additive for the shielding driving method is produced by using a slurry of coal ash such as flyash as a base and, optionally, adding bentonite, porcelain clay or the like to it. This additive is used as a plastic flow improver poured into dug earth and sand taken in an earth pressure-type shield chamber. In this way, it is possible to lengthen the pressure transfer distance while retaining a high viscosity and a high concentration. By forming a slurry material supplied to a slurry-type shield chamber from a composition containing a coal ash slurry, it is possible to obtain a slurry material which is lowly degradable, has a specific gravity smaller than that of porcelain clay and is resistant to sedimentation.</p> |
