| 摘要 |
PROBLEM TO BE SOLVED: To provide a tunnel construction method capable of relieving residual thrust in the axial directions of a tunnel and moving segments by dissolving friction between rings. SOLUTION: The natural ground 1 is excavated to form a tunnel 3. Then a transmission member 18 provided with ribs 17 for reinforcement and end plates 19 is installed as an axial force transmission member in the inner circumferential surfaces of segments 11a for adjustment arranged on both sides of both a segment 13a for widening at a predetermined position of widening and a flexible segment 15a in front of it. A residual thrust reception changeover mechanism 25, an axial-direction member comprising a support 23 and a jack 21, is installed between a pair of the end plates 19 of the transmission member 18. While relieving forces in axial directions acting on the segment 13a for widening by dissolution by the flexible segment 15a, the jack 21 is extended and contracted in axial directions of the tunnel 3 to change over the reception of the forces in axial directions by the residual thrust reception changeover mechanism 25 and move the segment 13a for widening in the direction of the outer circumference of the tunnel 3. COPYRIGHT: (C)2007,JPO&INPIT
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