Page - 1021 - in Book of Full Papers - Symposium Hydro Engineering

behaviour of the dam which will be a reference during its lifetime. The safety regulations of almost all developed countries determine special monitoring programmes during this particular phase. This paper presents some relevant results of the structural safety activities performed during the first filling of the reservoir of Baixo Sabor dam. After a brief description of the dam and its construction, the monitoring system, the monitoring plan during the first filling of the reservoir and some important results of tests carried out for the characterization of the material rheological properties are presented. The interpretation of the monitoring results is based on their comparison with results of a numerical model that simulates the structural behaviour of the dam and its foundation. 2. BRIEF DESCRIPTION OF THE DAM 2.1. BAIXO SABOR HYDROELECTRIC SCHEME The Baixo Sabor hydroelectric scheme, in which the dam is integrated, is located on the Sabor river, in the north eastern part of Portugal. The scheme was designed and built by EDP Produção [1], and has been operated by this company. The scheme mainly consists of the dam, the underground powerhouse, excavated in the rock mass of the right bank, which includes the water intakes and the headrace tunnels upstream, as well as the tailrace tunnels downstream. The total installed power capacity is 171 MW, using two reversible units. The rock mass, on which the scheme was built, is of a good quality granite. However, it showed heterogeneous characteristics along the dam insertion surface as well as in the underground structures. 2.2. DAM CHARACTERISTICS The dam is a double curvature thick arch dam (Fig. 1) with 123.00 m high and a crest development and thickness of 505 m and 6.00 m, respectively. The crest and the normal water level (NWL) are at elevations 236.00 m and 234.00 m, respectively. The structure is divided into 32 blocks with approximately 15 m width near the right and the left banks and with 17 m width in the central blocks. The blocks are separated by vertical contraction joints, which were grouted to obtain a monolithic structure, after forced cooling of the concrete blocks. The dam has six horizontal inspection galleries spaced 20.00m in elevation. The reservoir volume is of about 1095 hm3 for the NWL [2]. 1021