WIDENING CONSTRUCTION METHOD OF EXISTING TUNNEL

• Main Authors: MATSUMURA TSUTOMU, SATO REIICHI
• Format: Patent
• Language: English; Japanese
• Published: 04.06.2020
• Subjects: EARTH DRILLING; FIXED CONSTRUCTIONS; GALLERIES; LARGE UNDERGROUND CHAMBERS; MINING; SHAFTS; TUNNELS

To provide a widening construction method of an existing tunnel for making it possible to execute a drilling construction to a lining construction on the widening part quickly and safely without performing traffic interruption in the widening construction of a cross section of the existing tunnel.SOLUTION: A side tunnel is constructed in the natural ground adjacent to an outer surface of a side wall of the existing tunnel, and a leg support structure is constructed to support a tunnel lining member of a widening tunnel in the side tunnel. An drilling work platform 44 having a frame surrounding the outer circumference of the existing tunnel is provided so that the legs are located inside the side tunnel. From the drilling work platform 44, a predetermined area of the outer peripheral natural ground of the existing tunnel is ring-cut to form a widened tunnel cross section. A precast concrete lining plate 40 that covers the inner surface of the cross section of the widening tunnel is sequentially loaded and assembled to support the upper half portion of the widening tunnel. The lining of the existing tunnel is crushed by using a working machine that can run on the protector in the existing tunnel to complete the widening tunnel cross section.SELECTED DRAWING: Figure 6 【課題】 既設トンネルの断面拡幅工事において、交通遮断を行うことなく、迅速かつ安全に拡幅部分の掘削工事から覆工工事までを行う。【解決手段】 既設トンネルの側壁外面に隣接する地山に側部トンネルを構築し、側部トンネル内に拡幅トンネルのトンネル覆工部材を支持する脚部支持構造を構築する。側部トンネル内に脚部が位置するように、既設トンネル外周を囲むフレームを有する掘削作業架台４４を配備する。掘削作業架台４４上から、既設トンネルの外周地山の所定範囲をリングカットして拡幅トンネル断面の形成する。拡幅トンネル断面の内面を覆うプレキャストコンクリート覆工版４０を順次搬入して組み立てて拡幅トンネルの上半部の支保を行う。既設トンネル内のプロテクタ上を走行可能な作業機械を用いて既設トンネルの覆工を破砕して拡幅トンネル断面を完成させる。【選択図】図６