PURPOSE: To simplify the execution by fitting an inner bit with anchoring member in a cylindrical casing comprising a bit in the tip thereof freely to be disconnected, and drilling the natural ground, and thereafter, filling the consolidating material, and while drawing only the casing out.
CONSTITUTION: An inner bit 2 is fitted in a cylindrical casing 1 comprising a bit in the tip thereof freely disconnected without rotation, and a bar-shape or a rope-shape anchoring member 3 is connected to the inner bit 2. At the time of connecting the anchoring member 3, a swivel joint or the like, which does not transmit the rotation, is used at need. Next, the casing 1 is rotated to drill the natural ground, and thereafter, the consolidating material such as mortar is filled into the casing 1, and while the casing 1 is drawn out, and the anchoring member 3 is fixed. The execution efficiency is thereby improved.
KOKUBU SHIGEO
OHARA TAKAHIKO
