Experience in the construction and first years of operation of the Zeya dam

Abstract

The site of the Zeya hydroelectric station is located in a gorge whose width at the water's edge is 350 m. The mean annual air temperature in the region of the construction site is --4.1~ the mean monthly temperature of the warmest month (July) is +18.6~ and of the coldest month (January) --30.1"C.The mean annual temperature during construction of the main structures varied from +0.4 to --2.5 ~ .An intrusive mass of dlorltes serves as the foundation of the structures of the hydrostation. The diorites are intersected by several zones of tectonic disturbances with a thickness from 0.2 to 3 m.The modulus of deformations of the foundation varies from 3-10" to 2.104 MPa and averages 1.3.104 MPa. The indices of the shear strength of the concrete with respect to the dlorites are: friction coefficient 0.70 and cohesion 0.03 MPa. The specific water absorption of the rocks is from 0.01 to 0.005 dmS/mln (in rare cases it was 1 dm'/mln~.The barrier of the Zeya hydrostation is formed by a buttress dam with a crest length of 714 m and maximum height of l12 m. The volume of concrete in the dam is 2,160,000 m'. The dam has a triangular profile with upstream and downstream slopes of, res~ectlvely, 1:0.15 and 1:0.8.The buttresses with a 7 m thickness on the spillway part and 5 m on the powerhouse part on the upstream side have massive heads.The thickness of the head varies with height from ii to 6 m. On the downstream side the hollows between the buttresses are covered with 3.5-m-thick slabs on the spillway part and 1.5-m-thick slabs on the nonoverflow parts [i]. The width of the spillway section is.15 m and of the powerhouse section 24 m.