To demonstrate a reinforcement effect by steel pipes with high uniformity, to provide a suitable natural ground restraining effect without performing additional reinforcement during tunnel excavation work, and to enable execution at a low cost in various excavation systems, related to a natural ground reinforcement method of long steel pipe forepoling work and long mirror reinforcement work to be placed from a tunnel excavation space for instance.
In connection of the long steel pipe forepoling work and the long mirror reinforcement work formed by executing drilling at a prescribed elevation angle inside the natural ground at a working face front part from the tunnel excavation space and successively connecting a plurality of steel pipes having a discharge hole of a consolidation material on a peripheral wall simultaneously, for the steel pipe for natural ground reinforcement, diameter enlargement work on a female screw side and diameter reduction work on a male screw side are executed, and several belt-like projections and recesses are provided on an outer peripheral surface of a reinforcement pipe body.
WASHIO HIROSHI
KUDO CHOHEI
WASHIO HIROSHI
KUDO CHOHEI