Stress history effects on graded bed stability

Heather Haynes, Gareth Pender

    Research output: Contribution to journalArticle

    34 Citations (Scopus)

    Abstract

    This paper presents the first detailed examination of the dependence of graded bed stability on antecedent flow conditions (stress history). Thirty-three experiments, including repetitions, were undertaken where a bimodal sediment bed (D50=4.8mm, s8=2.1) was conditioned for between 30 and 5,760 min. The antecedent shear stress ranged from 53 to 91% of the critical shear stress for the D50 of the sediment bed. Data indicate that higher antecedent shear stresses reduce bed stability due to selective entrainment of the fine matrix; conversely, extending the duration of the antecedent conditioning phase increases bed stability due to local particle rearrangement. Analysis of the competitive effects indicates that particle rearrangement may be of greater relative importance than compositional change. Overall, the paper demonstrates the significance of antecedent flow conditions for hydraulic engineering and research, including the modeling of bed-load transport during flood events and the need for standardizing the flume-based experimental procedure. © 2007 ASCE.

    Original languageEnglish
    Pages (from-to)343-349
    Number of pages7
    JournalJournal of Hydraulic Engineering
    Volume133
    Issue number4
    DOIs
    Publication statusPublished - Apr 2007

    Keywords

    • Floods
    • Stability
    • Streambeds
    • Stress

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