Affiliation:
1. Department of Applied Sciences, University of Quebec at Chicoutimi, Chicoutimi, QC G7H 2B1, Canada
2. Hydro-Québec Production Unité Expertise en Barrages, 75 Boulevard René-Lévesque Ouest, Montréal, QC H2Z 1A4, Canada
Abstract
Erosional incidents have heightened the necessity of studies regarding rock mass erosion in unlined dam spillways. Enhanced comprehension of hydraulic erodibility necessitates an investigation into the geomechanical and hydraulic aspects of erosional phenomena. Controlled blasting is commonly employed to establish unlined spillways in rock masses, and this process results in irregularities along the spillway surface profile. Recent research has identified key geometric parameters of rock masses that impact erosion in unlined spillways, such as joint opening, dip and dip direction, and joint spacing. However, the effect of spillway surface irregularities on hydraulic parameters remains uncertain. Numerous studies have examined the surface roughness of rock at the millimeter scale within the domain of hydraulic engineering. Despite these efforts, a noticeable gap persists in our understanding of how surface irregularities specifically exert influence over hydraulic parameters. Currently, there is a lack of a clear equation or methodology to incorporate irregularities into hydraulic erosive parameters. The main aim of this study is to show how such irregularities affect the hydraulic parameters. This study is dedicated to emphasizing the importance of considering these irregularities. Building upon the findings obtained, the core aim of this research is to facilitate the formulation of an equation in future investigations that effectively accounts for these irregularities when calculating hydraulic erosive parameters. To assess the significance of surface irregularities in unlined spillways, computational fluid dynamics (CFD) with ANSYS-Fluent software was employed to analyze 25 configurations of spillway surface irregularities and their effects on various factors, including pressure (total, dynamic, and static pressures), shear stress, flow velocity, and energy. The findings indicated that irregularities significantly influenced the hydraulic parameters. Specifically, an increased irregularity height led to a decrease in maximum velocity, total pressure, and shear stress. Conversely, total energy loss increased, amplifying the rock mass’s vulnerability to erosion due to these irregularities.
Funder
Natural Sciences and Engineering Research Council of Canada
Subject
Water Science and Technology,Aquatic Science,Geography, Planning and Development,Biochemistry
Reference33 articles.
1. Pells, S. (2016). Erosion of Rock in Spillways, University Of New South Wales.
2. Rock, A.J. (2015). Semi-Empirical Assessment of Plunge Pool Scour: Two-Dimensional Application of Annandale’s Erodibility Index Method on four Dams in British Columbia, Canada, A. Colorado School of Mines, Arthur Lakes Library.
3. Jalili Kashtiban, Y., Saeidi, A., Farinas, M.-I., and Quirion, M. (2021). A Review on Existing Methods to Assess Hydraulic Erodibility Downstream of Dam Spillways. Water, 13.
4. Blake, W., and Hedley, D.G. (2003). Rockbursts: Case Studies from North American Hard-Rock Mines, SME.
5. Assessment of rock mass erosion in unlined spillways using developed vulnerability and fragility functions;Saeidi;Georisk Assess. Manag. Risk Eng. Syst. Geohazards,2020