Backfilling material injection apparatus for shield tunnel lining of drainage type using precious slag (ps) ball, and method for the same

Provided are a backfill material injection apparatus for a drainage shield tunnel lining using precious slag (PS) balls, and a method thereof. The backfill material injection apparatus is able to accurately and easily inject PS balls which have excellent permeability and filling performance as backfill materials for a drainage shield tunnel, into a backside common duct such that underground water is able to smoothly be introduced and drained into the shield tunnel. Accordingly, the backfill material injection apparatus uses the PS balls as the backfill materials, thus removing environmental problems such as pollution of underground water or the like; and has superior water permeability and filling performance such that a space is able to be sealed in a single filling instance with air pressure. As such, additional filling work is not necessary. In addition, the backfill material injection apparatus for the drainage shield tunnel lining of the present invention builds the shield tunnel by considering a concept of a drainage tunnel in which water pressure has not been considered, thus obtaining economical effects such that a thickness of a segment lining may be reduced up to 20-50% and that the manufacturing costs of the segment lining and distribution costs may be reduced up to 10-30%. To this end, the backfill material injection apparatus comprises: a PS ball supply hopper which stores and supplies the PS balls; PS ball transfer units having air hose fastening members and outlet holes; a PS ball transfer hose fastened to the outlet holes of the PS ball transfer units; a transfer hose outlet port formed on an end portion of the PS ball transfer hose; an air hose whose one side is fastened to the air hose fastening members; and an air compressor fastened to the other side of the air hose to supply compressed air to the PS ball transfer units.