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Master Thesis
Department of Hydraulic and
Environmental Engineering
Riprap on Rockfill Dams
– Displacement of Riprap and
Applications of Smartstone
Sensors
By Jens Jakobsen
Supervisor: Priska Helene Hiller
and Jochen Aberle
Background
Example of a rockfill dam with riprap protection.
A smartstone sensor.
Riprap considerably increases the stability of a
slope and its resistance against erosion. Therefore,
the downstream slopes of rockfill dams built in
Norway after 1950 are armed with a riprap by
placing oblong stones in an interlocking pattern.
Despite that Norwegian dams the last 30-40 years
have been built with a riprap design, there is not
a lot of knowledge about this building technique.
Therefore, in 2011 a research project was initiated
by Energy Norway to increase the knowledge
about riprap on the downstream slopes of rockfill
dams, and in February 2013 a PhD study started
about the topic. This Master thesis is a part of a
that PhD study.
The objective of this master thesis is to test «Smartstones», a newly developed sensor which
can be placed inside of stones in the riprap. The sensor includes accelerometer, e-compass
and gyroscope to register movements. It is a prototype and not yet fully developed.
Laboratory tests will be conducted in a flume,
where the downstream side of a scaled
rockfill dam will be built. The upper layer will
be constructed as riprap and sensors will be
placed inside some of the stones. Water will
then flow over the riprap and movement in
the sensors will be registered. This master
thesis will mainly look at displacement and
how that can influence the stability of the
riprap.