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ARS Home » Research » Publications at this Location » Publication #84081
Title: DEVELOPMENT OF EXCESS SHEAR STRESS PARAMETERS FOR CIRCULAR JET TESTING

Author
item Hanson, Gregory
item Cook, Kevin

Submitted to: American Society of Agricultural Engineers Meetings Papers
Publication Type: Proceedings
Publication Acceptance Date: 8/14/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary: Concentrated channel scour around bridges and highways, as well as the treatment costs for stream bank erosion, is over a billion dollars annually. In some areas of the United States, gully and streambank erosion account for 40% or more of the total erosion. Therefore, prediction of the erodibility of soil material by concentrated flowing water is important for renvironmental management of erosion and sedimentation. This paper describe the development of analytical procedures for characterizing soil erodibility utilizing a scour testing apparatus. Scour tests utilizing a submerged jet apparatus provide a simple approach to making measurements of erosion resistance. The erosion resistance of four soil materials is evaluated based on this development. The results are consistent with earlier results on these four soils, confirming that this procedure can be a valuable tool for engineers and geologists involved in design and maintenance of structures where scour has traditionally been a problem.

Technical Abstract: The excess shear stress equation is often used to model the erosion of soil materials. The determination of the excess shear stress parameters, erodibility and critical stress, are important in the design of channels, spillways, embankments, bridges, and river restoration, as well as other landscape erosion settings. In this paper analytical procedures are developed for determining the excess shear stress parameters from circular jet scour test results. Scour tests from four soil materials are evaluated for critical stress and erodibility based on this analytical development. The results are consistent with earlier results of open channel tests. A general relationship is observed between the critical stress and the erodibility. Soils with a low critical stress had a high relative erodibility, and soils with a high critical stress had a low relative erodibility.