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Operation of the dam in a transitional mode is described.The gravity dam of the Bureiskaya HPP has a compound profile in contrast to other domestic dams of the type erected under severe climatic conditions. The first pile is made of vibrated concrete and the downstream wedge (DW) is made of rolled concrete. The joining is ensured by a 2-m pile from layer-by-layer vibrated concrete placed simultaneously with the rolled concrete [1].Field observations at the Bureiskaya HPP are performed as designed, which makes it possible to follow the temperature fields of the controlled sections, the seepage conditions, the displacements of the body of the dam, the settlement of the foundation, the stresses in the concrete, and the condition of block and pile joints. In the autumn of 2004 (startup of the third generating unit) instrumental studies were carried out with the help of 1786 remote gages, 4 direct and 6 inverse plumb lines, and 92 piezometers.As a rule, the operation of a dam is considered in the stage of design under the assumption that it is monolithic. It is assumed that the pile joints are grouted appropriately, cracks and openings of construction joints are absent, and the scheme of static operation us thus invariable. However, any operating dam is characterized by disturbances of the monolithic nature of the operating profile not stipulated in the design (the temperature opening of construction joints on the downstream and pressure faces is allowed for when the computational models are refined in the period of the construction).The first task in an analysis of field data is the determination of the actual disturbances of solidity of the erected structure and their effect on the stress-strain state (SSS) of the dam.The solidity of the erected concrete structures at the Bureiskaya HPP is disturbed due to three main factors typical of gravity dams, namely, the temperature-induced formation of cracks, the opening of horizontal construction joints between blocks, and inappropriately grouted joints between piles.Temperature-induced cracks of the construction period. Temperature-induced formation of cracks is an inevitable phenomenon in the construction of dams, especially under conditions of severe climate. In the Bureya dam low crack resistance is typical for the blocks of walls of bottom holes that are fully frozen in winter and for low levels of individual blocks concreted in the period of 1988 -1995, when they froze for years having no neighbors. In addition, the composition of the concrete differed from the design one. Instrumental observations showed the presence of 17 cracks of which 5 cracks were opened by more than 0.4 mm, 10 cracks were located in the bottom part of the dam (up to the level of 155.0 m), 5 vertical cracks formed in blocks on the side of the pressure face, 5 vertical and inclined cracks passed in the center of blocks, and 7 cracks passed on the side of the downstream face of piles I and II and of the downstream wedge.The through vertical cracks going in the direction of the axis of the structu...

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