| 摘要 |
PROBLEM TO BE SOLVED: To prevent water from accumulating by providing a drain ditch in the central part of the planar bottom face of an underground multi-service pipe line having a circular section and providing a drain pit in a position communicating with the ditch. SOLUTION: An underground multi-service pipe line 1 constructed by the shield tunneling method is formed to have a circular section and the bottom face 2 is formed to be planar. Then, a drain ditch 3 is formed at the central part of the bottom face 2. And further, a drain pit 4 is provided at an appropriate position communicating with the drain ditch 3. The underground multi- service pipe line 1 is constituted of a primary lining layer 11 composed of segments and a secondary lining layer 12 formed of concrete. The drain ditch 3 is formed in the secondary lining layer 12. Accordingly, a little water arising from dew condensation or water leakage, etc., is collected in the drain pit 4 through the drain ditch 3 and easily removed by a pump or the like. Hence, accumulation of water in the underground multi-service pipe line 1 can be prevented.
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