Title

Consolidation settlement potential in south Louisiana

Document Type

Conference Proceeding

Publication Date

1-1-1993

Abstract

Primary consolidation is an important cause of wetland loss in active and recently abandoned deltaic plains in south Louisiana. Argillaceous and organic facies are most subject to reduction in volume, and experience great changes with minimal loading. Sampling with traditional vibracores, which induce compaction in the near-surface, has proven inadequate to obtain baseline on the zero consolidation point in these critically sensitive soils. For this reason, a liquid nitrogen annulus core method was developed for obtaining in-situ samples within the consolidometer trim ring. Four facies types were selected for consolidometer modeling inn the greater Mississippi River deltaic plain at the time of this publication. Although testing is incomplete (four facies types remain to be tested), two end-members of the consolidation spectra have been identified; sands and organic fat clays (i.e. SP and CH soils in the Unified Classification, respectfully). Results indicate that sand facies accumulate rapidly, do not readily consolidate, and form elongate loads which deform underlying, sensitive clays. Conversely, clay and organic soils accumulate in broad, inter-distributary basins, and are subject to drastic volume changes upon loading. The uppermost 10 meters (the Lafourche Delta in our study area) is most subject to further consolidation settlement.

Publication Source (Journal or Book title)

Coastal Zone: Proceedings of the Symposium on Coastal and Ocean Management

First Page

1197

Last Page

1214

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