Geotechnical News • June 2015
17
GEOTECHNICAL INSTRUMENTATION NEWS
Introduction by John Dunnicliff, Editor
This is the 82nd episode of GIN.
One article this time, a discussion and
a closure.
Use of the ShapeAccelArray
(SAA) in a rockfill dam
The article by Marc Smith compares
settlement data collected from an SAA
with data collected from a conven-
tional horizontal inclinometer during
the recent construction of a rockfill
dam. There is clear preference for the
SAA.
Because data collection will be ongo-
ing, the author has agreed to send me
a contribution for GIN in about three
years’ time, to update us on the accu-
racy and durability of the SAA, by
which time it will have been in place
for about six years.
Discussion and closure of article
in December 2014 GIN about
wireless monitoring
The discussion by Adam Dulmage and
Matt Trenwith of “The fundaments of
wireless monitoring – things to con-
sider” by Simon Maddison is followed
by a closure by the author.
Another corporate update
In March 2015 GIN I reported on
several corporate changes, notably
the acquisition by Nova Metrix LLC,
Woburn, MA
)
of various instrument manufacturers
with familiar names. Nova Metrix has
now acquired Schlumberger Water
Services Technology Group, which
is comprised of Westbay Instruments
and Waterloo Hydrogeologic. Those
two companies will be familiar to GIN
readers as manufacturers of multipoint
piezometers.
What are the characteristics of
an engineer?
An astronomer, a physicist, and an
engineer were travelling north from
London by train. They had just crossed
the border into Scotland, when the
astronomer looked out of the window
and saw a single black sheep in the
middle of a field. “All Scottish sheep
are black,” he remarked. “No, my
friend,” replied the physicist, “
Some
Scottish sheep are black.” At which
point the engineer looked up from his
paper and glanced out of the window.
After a few seconds thought he said
blandly: “In Scotland, there exists at
least one field, in which there exists
at least one sheep, at least one
side
of
which is black”.
Closure
Please send an abstract of an article
for GIN to
—see
the guidelines on
news.com/instrumentation_news.php
Eis Igian (Greece)
Performance of a ShapeAccelArray (SAA) for settlement
monitoring of a large rockfill dam
Marc Smith
Introduction
A ShapeAccelArray (SAA, www.
measurandgeotechnical.com) was
installed alongside a conventional
horizontal inclinometer (INH) dur-
ing the recent construction of a dam.
This setup allowed the comparison of
settlement results from both types of
instrument and helped gain confidence
in the relatively new SAA technology
for embankment dam engineering.
This article shows Hydro Québec’s
(Canada) experience with the per-
formance of a SAA used to monitor
settlements in a large rockfill dam dur-
ing its construction. This experience is
based on a dam safety context where
instrumentation is permanent and
expected deformations are relatively
small and progress slowly.
Dam cross section and
instrumentation
The Romaine-2 dam is a 112 m-high
asphalt core rockfill structure part of
the Romaine-2 hydroelectric project
located in northern Québec, Canada.
Dam construction took place mainly in
2012 and 2013 after river diversion by
means of two cofferdams. Reservoir
impoundment started during spring
2014.
The asphalt core has a width varying
from 0.85 m at its base to 0.5 m near
the crest. It is flanked on both sides by
support and transition zones (3M and
3N) having maximum particle sizes of
