Abstract
A back-filling method has been developed, which uses, as a refilling material in the field, the most-difficult-to-handle excess slurry produced from the slurry shield method. A solidifying agent is added to the excess slurry to obtain a viscous fluid, which is then transported for back-filling. This report describes the various experiments necessary to implement this method in the actual work and the results of trial applications based on the experimental result. This method can reduce to a minimum the transfer of excess slurry to the outside and the consumption of pit sand for back-filling, thereby contributing to the conservation of the natural environment.
