| 摘要 |
PURPOSE:To restore excavation surplus soil to the nature in a short time by adding an aluminum salt to the soil containing additives comprising an anionic water-soluble polysaccaride and/or a water absorbent resin. CONSTITUTION:In a soil pressure type shield construction process, excavated earth and sand, after being mixed with an anionic water-soluble polysaccaride and/or a water absorbent resin, is discharged as excavation surplus soil through an earth and sand transportation pipe. The soil containing additives is mixed with an aluminum salt, especially potassium alum, so that the anionic water-soluble polysaccaride, e.g. carboxymethyl cellulose sodium salt (CMC), is made water-insoluble to be fixed in the soil. Aluminum acetate, etc., can be used in place of potassium alum; however, potassium alum is the most preferable in view of safety. The amount of the alum to be added is 20-100wt.% to the total of CMC and the water absorbent resin contained in the soil. |
