| 摘要 |
A granular stone column drill which includes a first drill, a second drill and a displacement device, where - the first drill includes a tube within which the second drill at least partially, co- axially, lies; - the second drill includes a drill flight and first terminal end; - the displacement device includes a displacement unit and at least one guidance means; - the displacement unit includes a guide channel and an exposed wall such that the guide channel extends into the exposed wall; - the exposed wall lies approximately parallel to a centreline of the second drill; and - the at least one guidance means are located within the guide channel; such that the guide channel is a continuous circumferential channel that follows a wave like path, and either the at least one guidance means or the displacement unit is releasably or permanently attached to the second drill. |
