FIG Peer Review Journal


Measuring Inclinations in Cabril Dam with an Optoelectronic Sensor (5507)

Maria Henriques, José Lima and Sérgio Oliveira (Portugal)
Eng. Maria Henriques
Research Officer
National Laboratory for Civil Engineering
Av. Brasil 101
Corresponding author Eng. Maria Henriques (email: mjoao[at], tel.: +351 218443396)

[ abstract ] [ paper ] [ handouts ]

Published on the web 2012-03-08
Received 2011-11-01 / Accepted 2012-02-02
This paper is one of selection of papers published for the FIG Working Week 2012 in Rome, Italy and has undergone the FIG Peer Review Process.

FIG Working Week 2012
ISBN 97887-90907-98-3 ISSN 2307-4086


A high precision inclinometer was placed in the top gallery of Cabril dam, the highest dam in Portugal (132 m). Cabril dam presents, since the first filling of the reservoir (1953), some horizontal cracks in the central upper zone. The dual axis inclinometer, which was recording with a measuring rate of 1 Hz, was mounted during two days; during the same period a digital thermometer, recording air temperatures, was placed next to the dam’s downstream face. The dam was under normal operating conditions: the power generation groups are on or off for periods of variable duration during each day. The presented analysis of the collected data (inclination measured at a point near the dam crest, in two directions, and air temperature and reservoir level) shows a good correlation of the variations of the inclination with the daily thermal wave and with the changes of the reservoir level. The analysis also shows the reliability of the optoelectronic sensor since it was able to detect the vibration induced by the power groups. The inclination measurements were undertaken in connection with a test of a fully automated geodetic system for continuous monitoring of displacements of Cabril dam.
Keywords: Engineering survey; Deformation measurement