LARGE CLOSED CONDUIT CHECK DAM

摘要

PROBLEM TO BE SOLVED: To reliably dam up a debris flow by automatically blocking up a close conduit part by rolling of a sphere at debris flow and volcanic mud flow time by arranging a glass bead-shaped gate having a diameter larger than a width of the closed conduit part in the upstream part to a dam main body having the closed conduit part. SOLUTION: A closed conduit part 2 is arranged in a dam main body 1, and a glass bead-shaped gate 3 having a diameter larger than a width of the closed conduit part 2 is arranged in the upstream part. The size of the closed conduit part 2 is formed in the size of making a peak flow rate flow down at medium/small scale flood time without being dammed up and of not blocking up the closed conduit part by capturing a huge stone and driftwood supposed to flow down at this time, and is also formed smaller than a diameter of the glass bead-shaped gate 3. The glass bead-shaped gate 3 is made of a concrete sphere to block up the closed conduit part 2 by rolling by fluid force at debris flow and volcanic mud flow time when arranged in an upstream part of a dam. Earth and sand are made to flow downstream through the closed conduit part 2 at ordinary time and medium/small flood time, and the closed conduit part 2 is blocked up at debris flow and volcanic mud flow time without a power unit to reliably capture earth and sand and huge gravel.