The Geodesic Monitoring of the Great Dams

CGEOS - Creative Geosensing - is the leading Walloon company specialising in the positioning of high-definition 4D, offering its services as an integrator of geodesic and geotechnical sensors and solutions for the auscultation and monitoring of civil engineering structures.

With more than 30 years' experience in this area, CGEOS made a critical contribution to the largest auscultation project of four hydro-electric stations in Ukraine from 2010 to 2014 by creating a new design and specifying all the instrument and software provisions. Furthermore, in 2014 CGEOS acted as a consultant for the commissioning of this World Bank-funded project. The consultant for this project, Electricité de France, awarded the maximum number of points to this proposal, recognising that it was a real revolution in this area.

Although in the past the auscultation of large dams was carried out using theodolites and high-definition total stations, together with long and costly levelling operations, GNSS now makes it possible to provide millimetric solutions using just one frequency of the GPS, GLONASS and BEIDOU constellations.

CGEOS has innovated by coupling a switch to a GNSS receptor so that it can be sequentially connected to four or eight antennae and obtain their positions to the nearest millimetre. This has significantly reduced the investment costs for this type of installation and it is now possible for many public and private organisations to no longer use only visual inspections, that are often biased, and to obtain all the data and the analysis of the behaviour of these structures via a web application.

For CGEOS, it simply involves taking part in the digital plan for Wallonia by proposing innovative civil engineering methods.

With its involvement in auscultation projects for large dams in Ukraine, Lithuania, China and Indonesia, as well as Nigeria, Greece, Russia and Italy, CGEOS wants to make its expertise available to large dams in the Walloon Region.