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Department of Civil
and Environmental
Engineering
2015 - 2017
Riprap Design for
Rockfill dams
Supervisor:
Leif Lia
Co-supervisor:
Jochen Aberle
Priska Helene Hiller
PHD THESIS
Background
Downstream slopes of Norwegian rockfill
dams are strengthened with a placed riprap
against accidental overtopping or considerable
leakage through the dam. Stones are placed in
an interlocking pattern with their longest axis
inclined towards the dam axis as shown in the
figures. The current guidelines are based on
the knowledge about dumped riprap despite
the fact that the stones have to be placed in an
interlocking pattern. Hence, there is need for a
better understanding of the additional strength
gained by placed riprap.
Objectives of the study
•
Literature study of riprap design and
practical solutions for steep slopes
•
Identification of the hydrodynamic forces
due to the flow over steep slopes and flow
through the riprap
•
Execution and analysis of laboratory tests
and large-scale field tests
•
Identification of the relevant parameters of
the riprap material as well as the effect of
placement patterns
This study is financed by Energy Norway and the
Research Council of Norway. The support of the
collaborating companies in the project “PlaF” is
kindly acknowledged.
Rehabilitation of Svartevatn dam: placement of riprap
stones on the downstram slope
(Photo: NTNU)
Drawing of placed riprap