| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a branch tunnel constructing segment, advantageous for enhancing construction efficiency of branch tunnel in construction of a branch tunnel from a master tunnel. <P>SOLUTION: The segment S comprises a segment body 12, a plurality of through-holes 14, and a first cap 16. The plurality of through-holes 14 are provided in mutually separating positions of the segment body 12 to extend through in the thickness direction. The through-hole 14 is formed by the inner circumferential surface of a pipe 26 embedded in the segment body 12. The first cap 16 blocks the through-hole 14 on the outer circumferential surface 24 of the segment body 12. The first cap 16 is formed of a material easy to crush by a drilling and chemical injecting rod 52. Otherwise, the first cap 16 is provide to be removable out in the radial direction of the segment body 12 when the rod 52 is pushed to natural ground G through the through-hole 14. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
