GEOLOGY OF BACKSWAMP DEPOSITS IN THE ATCHAFALAYA BASIN, LOUISIANA.
Abstract
New interpretative methods, based chiefly on X-radiography, were developed and applied for the purpose of subdividing and correlating the backswamp deposits underlying most of the Atchafalaya levee system. Observations were made also of details of fracturing and plastic deformation in the soils, as well as presence of organic matter, secondary mineralizations, burrowing, and other features. It was observed that most of the foundation settlement caused by levee loading occurred in the upper 50 ft of underlying soils but often an important part of the total settlement of the levee crown occurred within the levee fill. Naturally occurring shell horizons or sand and silt layers appear to distribute loading so that underlying soils are less affected by settlement. Where there is abundant organic matter, settlement is accompanied by plastic deformation as well as fracturing in clays. Where there is no organic matter, disturbances in clays are more often accompanied by fracturing. Clay horizons that were burrowed by invertebrates or contained an abundance of carbonate nodules appeared to have a relatively lower susceptibility to disturbance. Current studies indicate that strength parameters for given depositional conditions will be practical and will aid in preliminary interpretation of foundation conditions. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1969
- Accession Number
- AD0695617
Entities
People
- Ellis L. Krinitizky
- Frederick L. Smith