| 摘要 |
A height control manhole is provided to be easily installed in a road repairing field for additionally covering asphalt concrete. A height control manhole is composed of a cover(20), an outer frame(30) which is composed of an anti-slip multi-stage groove(32) in which a projection portion(34) and a groove portion(36) are formed in zigzag, and a reinforcing frame(30) is formed in the backplane, and an inner frame(40) which is installed between the cover and the outer frame and has an anti-slip projection(45) corresponding to the anti-slip multi-stage groove. |
