| 摘要 |
PROBLEM TO BE SOLVED: To provide a construction method for a head-enlarged pile, which enables efficient and safe construction while preventing the mixing of excavated soil, causing a decrease in the end bearing capacity of the pile, by utilizing a preboring method. SOLUTION: A casing 2, the spiral blade 2a of which is provided on its outer periphery, and a drill rod 3, which passes through the casing 2, are inserted into ground while being rotated, so that a hole 4 for pile construction can be bored. An upper portion of the hole 4 is cut by pulling out the casing 2 while rotating it, so that a diameter-enlarged portion 4a can be formed in the upper portion of the hole 4. Next, a prefabricated pile is erected in the hole 4 by using the casing 2 as a guide, so that a main body portion 1b of the head-enlarged pile 1 can be formed. Subsequently, the casing 2 is removed, and a head-enlarged portion 1a of the head-enlarged pile 1 is formed in the diameter-enlarged portion 4a after that. COPYRIGHT: (C)2008,JPO&INPIT
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