| 摘要 |
PROBLEM TO BE SOLVED: To suppress leakages by through the utilization of the pressure of underground water by embedding a socket joint in the bottom section of an underground line box. SOLUTION: A hand hole 10 has a cylindrical side face 11 formed of nearly rectangular four faces around its nearly square bottom face 12, and an admission port 14 through its top face 14 facing the bottom face 14. In addition, a hole boring section 13 for laying conduit, etc., is provided in the lower section of the side face 11. Moreover, a circular drainage section 16 is formed on the bottom face 12, in such a state that the section 16 is made slightly lower than the bottom face 4 in order to accelerate the draining property of the section 16, and an exhaust port 16 is formed through the central part of the section 16 by embedding a socket joint 20 made of vinyl chloride in the central part. Namely, a cylindrical socket joint 20 the cross section of which the convex section is embedded with its larger-diameter portion on downward, namely, on the external surface side of the hand hole 10. When the supply is to be stopped at the time of embedding the hand hole 10 underground at such a plate that the underground water level is high, and so on, a blind plug is inserted into and stuck to the end connection 21 of the joint 20. |
