In Situ Assessment of Sediment Erosion and Consolidation State Using a Free-Fail Penetrometer: Sydney Harbour, Nova Scotia

摘要

Two in situ geotechnical surveys were undertaken in Sydney Harbour, Nova Scotia, Canada, following the dredging and relocation of 4.2 million m~3 of sediment from the shipping channel during the fall and winter of late 2011 and early 2012. The surveys were conducted 9 and 18 months after dredging using a portable, free-fall penetrometer. A new method for rapid assessment of the in situ state of sediment consolidation from free-fall penetrometer data was developed and applied to identify areas of sediment erosion and deposition. Results 9 months after dredging showed an initial accumulation of dredge-resuspended sediments. Eighteen months after dredging, stability, and evidence of consolidation or continued accumulation was found at more than 92% of the 39 sampled locations examined. Evidence of erosion was observed at only 3 locations. The general pattern of sediment stability observed is consistent with the historically low energy and sedimentation environment of the inner regions of Sydney Harbour.