Certain construction practices can lead to defects in drilled shafts. Defects can occur in the form of voids; degraded or debonded concrete; entrapped cuttings, slurry, or groundwater; and geometric errors. They are considered generically according to the place in theconstruction cycle at which the defect occurs: general defects, defects due to drilling, defects arising from casing management, defects arising from slurry management, and defects related to design. Examples are presented, and suggestions are made for post-construction integrity evaluation techniques that might be effective in locating a given defect and defining its extent. Methods are also suggested for avoiding defects, which often involve subtle factors. Because of modern construction techniques, experienced contractors, and knowledgeable inspectors, relatively few defective drilled shafts are currently constructed. This paper appears in transportation research record no. 1331, Integrity testing of foundations 1991
Samenvatting