| 摘要 |
A concrete slab which has settled is stabilized and may even be lifted by forcing a pier through the slab and into the underlying soil and then attaching the pier at its upper end to the slab. To this end a vertical hole is drilled through the slab as is a smaller oblique hole, with the latter intersecting and passing through the former. Then a jacking unit is attached to he upper surface of the slab around the vertical hole. The jacking unit forces a succession pier sections through the vertical hole and into the underlying soil, with these sections being fitted together end-to-end to form a pier. In time significant resistance is encountered, and at this point, while the jacking unit exerts a downwardly directed force on the pier and an upwardly directed counterforce on the slab, a hole is drilled through the portion of the pier that is within the slab, this being done by using the oblique hole in the slab as a guide for the drill bit. Then a pin is inserted into the oblique hole and driven into the aligned hole in the pier such that it projects from both sides of the pier and has its ends in the oblique hole. Thus, when the jack is removed, the pier supports the slab. |
