Repair, Evaluation, Maintenance, and Rehabilitation Research Program. Geotechnical Aspects of Rock Erosion in Emergency Spillway Channels
Abstract
Problems of rock erosion in unlined emergency spillway channels are described in this first-of-a series report. Recent case histories which illustrate the potentially hazard of excessive erosion in discharge channels are described as are various factors controlling erosion and other responses to emergency spillway overflow. Research to improve geotechnical capabilities with respect to selection of cost-effective preventive and remedial measures in discharge channels where the risk of excessive erosion appears high is also discussed. Response to emergency spillway overflow is controlled by such hydraulic and geologic factors as flood frequency and magnitude, engineering design, discharge channel gradient(s), discontinuity of earth materials, and erodibility of earth materials. A major controlling factor of erosion in spillway discharge channels lined by sedimentary strata appears to be the interrelated effect of stratigraphic discontinuity and channel gradient change(s). These factors combine to initiate and control headward migration of knickpoints, where resistant sedimentary layers are undercut by scouring of softer, underlying strata. In terms of erodability of earth materials, the scale of the hydraulic forces generated during emergency spillway overflows suggests that rippability and lithostratigraphic discontinuity may serve as a good point of departure in describing the relative resistance to erosion of rocks lining discharge channels.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1986
- Accession Number
- ADA173163
Entities
People
- Christopher O. Cameron
- Colin C. Mcaneny
- James H. May
- Kerry D. Cato