Construction settlements of the retaining shell on the vilyui hydroelectric station earth dam

Conclusions

• 1. The downstream retaining shell of the Vilyui hydroelectric station earth dam, erected from quarry stone without special measures for consolidating the fill, settled appreciably during the construction period. The maximum measured relative settlement was 6.75% in four years, with an embankment height of 42.5 m. It should be noted that total settlement is rather larger than the measured, since settlements were not measured below the layers existing prior to setting up the marks. Up to 50% of the total settlement of the embankment occurred within two to three months of its erection.

• 2. Increase of construction settlements occurs irregularly and depends on the fill-placing process. Following first filling of the reservoir, there is a further increase in settlement of the retaining shell (by 1.0–1.5%).

• 3. When constructing earth dams, overall settlement readings should be taken together with a study of the physical-mechanical properties of the fill, and the variation in properties in the course of time along with the temperatures within the fill. Measurement and control instrumentation should be provided in the design of such dams, enabling readings to be taken of the settlement on earch layer of rockfill throughout the entire construction period in accordance with a previously formulated program of readings.