| 摘要 |
PURPOSE:To reduce the cost of construction by winding a reinforcement squirrel- cage on a cylindrical steel pipe, hanging the steel pipe into a pit having a large diameter, placing concrete to a clearance between a pit wall and the steel pipe, excavating bedrock while stretching the cylinder and placing concrete into the hollow section of the steel pipe. CONSTITUTION:The soil and sand ground 1 is excavated to form a pit 2 having a large diameter up to the upper surface of bedrock 3. A cylindrical reinforcement squirrel-cage 6 is wound on the outer circumference of a cylindrical steel pipe 4 with a bottom expanded section 5, framed integrally and hung into the pit 2 having a large diameter and concrete is placed to a clearance between a pit wall and the steel pipe 4 and cured. Muddy water in the pit 2 having the large diameter is pumped up, the bedrock 3 is excavated up to predetermined depth while the reinforcement cylinder 6 is stretched and erected, and concrete is placed in the hollow section of the steel pipe 4 and the excavated pit of the bedrock 3. Accordingly, ring-shaped temporarily wound concrete placement work on the pit wall is unnecessitated, and concrete may be placed only in the hollow section of the steel pipe 4 and the excavated pit of the bedrock 3, thus reducing the cost of construction. |
