Condition of the concrete in the dam retaining the Kirov Reservoir on the Talas River in Kyrgyzstan

Abstract

Results of inspections of a concrete dam are presented.The massive-buttress dam retaining the Kirovsk Reservoir on the Talas River (Kyrgyzstan) was built in 1975 in accordance with a design developed by the "Kirgizgiprovodkhoz" Institute [1]. The dam is 84 m high, and has a crest length of 260 m, concrete volume of 310,000 m 3 , and a triangular profile with the thrust and downstream faces sloped at 0.45. The lower portion of the downstream face is at a greater incline (m = 0.70). The dam is divided by expansioncontraction and settlement joints into sections 22 m wide. Each channel section consists of a massive support haunch 22 m wide and a buttress 12 m wide, and a downstream haunch with a wall thickness of 4.5 m. Closed recesses 10 m wide are formed between the buttresses. The upstream haunches from the thrust face are curvilinear in plan with a radius of 28.1 m; this eliminates bending of the haunch in the cantilevered sections. Effective discharge ports are situated at elevation 832.0 m in sections 5 and 6. At its inlet, a port has a rectangular 3 × 4-mm section, which transitions to a circular section with a diameter of 2.2 m. The flow rate of water is regulated by conical gates. A surface spillway with a threshold at elevation 881.5 m is designed to draw down excess water in section 7 during a flood (Fig. 1).Two passageways 3 m wide and 3.5 high were specified at elevation 822.0 and 845.5 m for inspection of the internal surfaces of the concrete of the thrust haunches and buttresses, and also for observations of monitoring and measuring equipment. The passageway at elevation 822.0 m permits communication between channel recesses, and maintenance of equipment. The passageway at 845.5 m runs through the buttresses, and cuts into the bank. For open communication along the passageways, metallic bridges are established in the recesses. Metallic staircases and platforms, which provide for communication between the passageways are installed at various elevations and approaches to water levels.In conformity with the design, the dam was partitioned into three concreting zones, depending on the conditions under which the concrete was to function. The sections from the rock bed to elevation 836.0 m, and also the thrust haunches over their entire height were constructed of M250, R18, V8, and Mrz200 concretes. The buttresses and downyarsk Division of the JSC "Sibirskii Énergeticheskii Nauchno-Tekhnicheskii Tsentr," Krasnoyarsk, Russia. 886.5 (Normal backwater level) 888.5 832.0 815.0 836.0 822.0 845.5 m = 0 .4 5 m = 0 .4 5 77.0 1 1 Fig. 1. Section of dam through intersectional joint.