Field and model tests of riprap on steep slopes exposed to overtopping

Hiller, Priska Helene; Lia, Leif; Aberle, Jochen

doi:10.1080/23249676.2018.1449675

Cited by 12 publications

(5 citation statements)

References 19 publications

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“…This effect is compounded while dealing with rockfill dam structures built with narrow-steep abutment profiles (Figure 1). Ripraps comprising of large natural rock elements are employed in rockfill dams to protect the downstream slopes against erosion due to leakage or overtopping (Hiller et al 2019 andToledo et al 2015). Further, rockfill dam toes are commonly coupled with the downstream rockfill dam structure to control seepage flow in the zone where it exits the dam.…”

Section: Introductionmentioning

confidence: 99%

Effects of toe configuration on throughflow properties of rockfill dams

Kiplesund

Ravindra

Rokstad

et al. 2021

Journal of Applied Water Engineering and Research

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Section: Introductionmentioning

confidence: 99%

Effects of toe configuration on throughflow properties of rockfill dams

Kiplesund

Ravindra

Rokstad

et al. 2021

Journal of Applied Water Engineering and Research

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“…The coefficient of discharge values of each section for the fixed dam setup are calibrated and validated with the experimental data. This study provides such information, which may be of use in risk assessment as well as for the design of embankment dam riprap on the crest and on the downstream slope, see, for example, Hiller et al [34], for new and existing dams in landslide prone areas. This study is organized as follows.…”

Section: Introductionmentioning

confidence: 97%

Physical Model Study on Discharge over a Dam Due to Landslide Generated Waves

Tessema

Sigtryggsdóttir

Lia

et al. 2020

Water

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Impulse waves generated by landslides falling into reservoirs may lead to overtopping of a dam and, in turn, to flooding of the downstream area. In the case of an embankment dam, the overtopping may lead to erosion of the downstream slope, ultimately resulting in breaching and complete failure with consequent further hazardous release of water to the downstream area. This research deals with the overtopping process of a dam due to landslide generated waves in a three-dimensional (3D) physical scale model setup. Experiments have been conducted with varying the slide, reservoir, and dam parameters. The primary focus is on investigating the feasibility of employing the steady state weir equation in order to predict the overtopping discharge over a dam crest due to landslide generated waves. Calibration and validation of the coefficient of discharge values for the different dam section are conducted for the specified model setup. Accordingly, a two-step calculation procedure is presented for predicting the overtopping discharge based on the maximum overtopping depth values. Hence, for the fixed setup, which includes a constant slope angle of the landslide surface, a predictive equation for maximum overtopping depth is proposed, based on slide volume, slide release height, still water depth, upstream dam slope angle, and dam height. The relative slide volume and relative still water depth both seem to have a significant effect on the relative overtopping depth.

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“…If the crest is overtopped (Figure 2b,c), the downstream slope is then subjected to highvelocity, turbulent surface flow, provoking a progressive external erosion process that can lead to a dam breach. Ripraps are one of the most employed defence mechanisms for several in-stream hydraulic structures such as embankment dams, spillways, streambeds, riverbanks, bridge piers, and abutments [3][4][5][6][7]. For rockfill dam engineering, ripraps are encountered both on the upstream embankment and on the downstream slope.…”

Section: Introductionmentioning

confidence: 99%

“…A better understanding of the riprap structure and resistance against overtopping would help improve the reinforcement and building techniques. Ripraps are one of the most employed defence mechanisms for several in-stream hydraulic structures such as embankment dams, spillways, streambeds, riverbanks, bridge piers, and abutments [3][4][5][6][7]. For rockfill dam engineering, ripraps are encountered both on the upstream embankment and on the downstream slope.…”

Section: Introductionmentioning

confidence: 99%

Riprap Protection Exposed to Overtopping Phenomena: A Review of Laboratory Experimental Models

Dezert¹,

Kiplesund²,

Sigtryggsdóttir³

2022

Water

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There are increasing demands from dam safety regulations and guidelines to upgrade the rockfill dams, especially in Norway where over 180 large rockfill dams are present. To protect the hydraulic structure against overtopping events or leakages, it is important to use defence mechanisms such as a protective layer of riprap on the downstream slope. In this article, we display 9 experimental setups of riprap, conducted at the hydraulic laboratory of NTNU (Trondheim) and subjected to overtopping phenomena with increasing water discharge, until the complete failure of the model. These tests were performed on models with dumped and placed riprap, with or without toe support, with or without the downstream rockfill shoulder, and finally on models with a full dam profile. The models with downstream rockfill shoulder as well as with full dam profiles allowed for throughflow. The model behaviour during these experimental tests is described and discussed, according to their respective critical discharge values and associated failure mechanisms. Limitations are also discussed. The results bring to light the benefit of placed riprap compared to dumped riprap structures. As the results show a placed riprap can withstand a significantly higher overtopping discharge than a dumped riprap. Also, the use of toe support enables a significant increase of resistance against overtopping of placed riprap structures. However, toe supports have not proven any significant improvement in stability for dumped riprap structures. This research also puts forward that dumped riprap undergoes a surface erosion process with smaller slides. Placed riprap undergoes a sliding failure mechanism when unsupported at the toe, and a buckling deformation when supported.

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Field and model tests of riprap on steep slopes exposed to overtopping

Cited by 12 publications

References 19 publications

Effects of toe configuration on throughflow properties of rockfill dams

Effects of toe configuration on throughflow properties of rockfill dams

Physical Model Study on Discharge over a Dam Due to Landslide Generated Waves

Riprap Protection Exposed to Overtopping Phenomena: A Review of Laboratory Experimental Models

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