| 摘要 |
<p>Boring apparatus, comprising a screw shaft (3) for driving in rotation by a drive source (4), a down hammer (6) provided on a lower end of the screw shaft (3), the down hammer (6) being provided with a screw blade (5), at least one supply conduit (10,10',11,11') for cement milk or the like, a supply conduit portion (11,11') in the down hammer (6), and a pressure openable valve (12,12') disposed in the lower end region of the or each supply conduit (11,11',12,12'), whereby the cement milk or the like can be supplied to the inside of a bored hole. A method of forming an underground hole comprising boring a hole and, after completion of the boring operation and with the down hammer (6) down the hole, pulling up the down hammer while supplying cement milk or the like into the hole through the at least one supply conduit (11,11',12,12') to plaster the inner surface of the bored hole with cement milk or the like. <IMAGE></p> |
