| 摘要 |
PROBLEM TO BE SOLVED: To prevent an automobile or the like running on a road from causing ground subsidence by engaging a support block having a side surface at a predetermined angle in relation to the upper surface with a standing pipe standing from a drain conduit in the underground. SOLUTION: A ring-like table 5 is disposed on a standing pipe 3 for inspection or cleaning that stands from a merge measure 2 of a drain conduit 1, and a protective lid 7 is engaged with it. A foam-polystyrene-made support block 8 in a truncated shape whose diameter decreases from the upside to the downside is engaged with an intermediate part of the standing pipe 3. As a shape of the support block 8, a tilting angle of the back and frond surface 8A in relation to the supper surface 8B is preferably in a range of 30-60 deg.. After disposing the drain conduit 1, sedimentation S is back-filled, and a crushed stone layer M and an asphalt layer A are placed. The load of a running automobile from a ground surface SU is diffused in the direction shown by a dotted line, received by the support block 8, and moderated. This can effectively prevent ground subsidence near a lid portion of the standing pipe 3.
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