Concreting involved in the construction of the Vilyui hydroelectric power plant

Conclusions and recommendations

• 1. In the case of permanently frozen fissured rock, the steep slopes of excavations must be faced with concrete as soon as possible after exposure. If the lag between exposure and concreting is too long, the sides of the excavations suffer severe damage, owing to thawing of the ice in the fissures.

• 2. Preparation of a permanently frozen foundation for placing concrete involves much labor, time, and electricity for heating. The question of heating permafrost rock (and the extent of this heating) is now of great importance and must be studied.

• 3. Concreting in small blocks reduces the possibility of fissure formation, but requires much labor (3–4 men per day per 1 m³ of concrete). The work involved in preparing the blocks constitutes 80–85% of the total concreting operations.

• 4. Winter concreting in a severe climate is characterized by a marked reduction of the pace of the work, a sharp increase in labor costs (by a factor of 2–2,5) and in overall costs (by 53%).

• 5. Since the very nature of hydraulic construction requires the placing of large amounts of concrete in winter, a comprehensive group of machines and equipment (special concrete transporters, cranes, buckets, etc.) must be developed to ensure efficient concreting at temperatures in the range from −45 to −55°C.