Main requirements imposed on the quality of skeletal clay cores of rock-fill dams

Conclusions

• 1. Skeletal clay soil should be placed in the cores of high dams, with a water content which provides solid consistency of its fine portion (fractions with a diameter less than 2–5 mm).

• 2. Since the range of variation of the plastic limit of the fine portion can be close to the plasticity index, special attention must be given to elimination of the possibility of the fine portion, or some part of it, changing to a fluid-plastic state during construction or operation, which promotes undercompaction of the ocil, the occurrence of pore water pressure, delay of consolidation of the core, and occurrence of long-time deformations.

• 3. A comparison of the calculated values of the density and water content of the fine portion of skeletal clay soil of the core of the Nureksk dam with the results of laboratory investigations and an analysis of foreign experience in compaction showed that the main requirements imposed on the density-water content of soil are met in the case of its impact consolidation in the laboratory by work of 28,000 g-cm/cm³ according to the modernized AASHO method.

• 4. The parameters of density and water content of skeletal clay soils established by calculation and laboratory experiments should serve as the basis when selecting the optimal technological process of compaction, type of roller, and vehicles for delivering the soil to the dam core.