Monitoring of bottom strains during impoundment and operation of a large-scale experimental dam

Strains at the bottom of a large-scale experimental embankment dam were measured by fibre optics. The strains were measured in four sections, orthogonal to the dam axis. The fibre optic set up was operational after finalising the dam construction. The measurements were conducted continuously during the impoundment and later during the operation with an upstream water level of a maximum of 3.5 m. Based on the measurements, the post-construction behaviour of the dam was observed, indicating settlements. The foundation of the dam is inclined, which was captured by the measurements, with indications of more shear stresses developing at the downstream side. Variations of strains in the different dam zones were observed. The impoundment is causing most of the strain development in the dam. The strains develop further over time after the reservoir is at its maximum level, indicating a transient process is in place.