[Title Of Invention] Water Tight Bolt for Tunnel Segment Assembling [Technical Field] Tunneling work of civil engineering field [Background Art] Tunneling by Shield Tunnel Boring Machine applies engineering method in which the lining of the tunnel is installed after assembly of segments. Direct bolting method is commonly used in assembly of segments. Since there are often water leaks around the bolt in this method, however, a need for bolt with watertight structure arises.

[Disclosure of Invention] In order to prevent water leak in the direct bolt which is used in assembly of segments, watertight bolt is developed. The head (4) of such watertight bolt is shaped wide as if washer is attached to the bolt head rubber packing in order to allow rubber packing (2) to be inserted. Inserted rubber packing seals the gaps around the bolt as the bolt is screwed down. This new bolt is easy to manufacture and use in assembly of segments. It will reduce tunneling cost and maintenance cost for tunnels.

[Brief Description of Drawings] <Description for drawings> Drawing 1: Cross-sectional drawing of tunnel segments Drawing 2: Detailed drawing of tunnel connections Drawing 3: Structural drawing of Bolt

<Description for footnotes in the drawings> 1. Bolt 2. Rubber packing 3. Expansion rubber 4. Modified bolt head 5. Segment 6. External structure of tunnel 7. Internal structure of tunnel 8. Thread part [Mode for Carrying Out the Invention] The bolt head (4) will be shaped wide as if washer is attached to the bolt head rubber packing in order to allow rubber packing (2) to be inserted. These modified bolts will be used in assembly of segments.