| 摘要 |
PROBLEM TO BE SOLVED: To provide a fresh method for excavating a shield type tunnel which enables efficient construction of the tunnel without limitation to a driving speed even for a small-bore tunnel. SOLUTION: In this method for excavating a shield type tunnel, a segment member prepared by providing a plurality of lengthwise-parallel beam materials 42 at almost equal intervals inside a steel plate in the shape of a cut-and-divided tube formed by winding round an almost rectangular steel plate is introduced into a space in the rear of a shield type excavator which is formed by driving the excavator. An expanding device being introduced into a space inside the segment member subsequently, the outside diameter of the segment member is made to accord with that of a tunnel lining body, while the opposite end parts of the cut-and-divided parts are joined and shaped into a tubular body 41. Moreover, ring-shaped reinforcing members 43 each constituted by assembling a plurality of arc-shaped rib materials 43a and 43b are provided along the inner circumference of the tubular body 41 to form a steel segment 4, and after the steel segment 4 is joined to an existing segment adjacent thereto, excavation is advanced by driving the shield type excavator. The above processes in a series are repeated in succession.
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