Abstract
In recent years, as the number of reservoir embankments constructed has increased, embankment failures due to cracks in aging conduits have also increased. In this study, a crack in a conduit was modeled based on the current conduit design model, and the risk of internal erosion was analyzed using a large-scale model test and three-dimensional deformation–seepage analysis. The results show that when cracks existed in the conduit, soil erosion and cavitation occurred near the crack area, which made the conduit extremely vulnerable to internal erosion. Herein, a model is proposed that can reduce internal erosion by applying a layer of sand and geotextiles on the upper part of the conduit located close to the downstream slope. In the proposed model, only partial erosion occurred inside the conduit, and no cavitation appeared near the crack in the conduit. The results suggest that internal erosion can be suppressed when the water pressure acting intensively on the crack in the conduit is dispersed by the drainage layer. To validate these results, the pore water pressure, seepage line, and hydraulic gradient were investigated to confirm the erosion phenomenon and reinforcement effect.
Highlights
Old embankments can have high variability in their filling material because of the low level of compaction and are generally known to exhibit unique heterogeneity [1]. These characteristics result in uncertainty regarding the stability of an aging embankment due to structural defects, which can increase the potential risk in an emergency
It is highly dependent on the compaction of the embankment zone, the ratio of clay particles, the water content, and the erosion rate, and it is known to be caused by various factors, such as structural defects or construction failures inside the embankment [2,3,4,5]
The boundaries between a conduit structure constructed of concrete and the embankment zone, the impervious cores, and their shoulders can make the conduit more prone to internal erosion owing to the difference in material properties and differential settlement [6,7,8,9,10]
Summary
Old embankments can have high variability in their filling material because of the low level of compaction and are generally known to exhibit unique heterogeneity [1]. Internal erosion can be a threat to the future stability of the embankment due to cracks in the aging conduit It is highly dependent on the compaction of the embankment zone, the ratio of clay particles, the water content, and the erosion rate, and it is known to be caused by various factors, such as structural defects or construction failures inside the embankment [2,3,4,5]. The failure, due to internal erosion caused by a conduit crack, resulted in a concave circular shape being dug out around the conduit on the downstream slope, which gradually expanded to the top of the embankment. The results discussed in this study provide basic data that can be put into practical use on the embankment site of an old reservoir in the future
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
