Structural and technological concepts ensuring reliability of earth dams in the Far North

Conclusions

• 1. Despite the decisions made repeatedly at various conferences and seminars, there are still no scientific design guidelines. As a consequence of this, crucial decisions are made without sufficient substantiation and thorough evaluation of the decisions made.

• 2. Research institutes should not be limited to collecting data on settlements and temperature and seepage regimes of dams, but on the basis of data already available should give clear-cut standards and regulations for the design of earth structures in the northern construction-climatic zone.

• 3. The construction of transition zones between the rock fill of the downstream shoulder and foundation, drainage blanket, and relief drainage is mandatory in all cases when the foundation is composed of fractured rocks covered by a diverse stratum of loose soils of various origin.

• 4. The “core-filters-drainage” system should be a zone of increased attention when performing works and assigning the characteristics of the soils being placed.

  As far as possible, it is necessary to change to dam designs with narrow cores protected by transition zones and developed drainage. When constructing such dams in the winter, especially in the case of heavy snow falls, it is easier to check the quality of placing the material in the zone of increased attention — “core-filter.”

• 5. With consideration of deep freezing of the downstream shoulder of the dam and its differential settlements during thawing, in the northern construction-climatic zone it is necessary to do away with homogeneous dams and the construction of the downstream shoulder from skeletal soils with loamy sand or loam filling. The downstream shoulder should be constructed from rock fill as the most adapted to differential settlement in a frozen state.