سال انتشار: ۱۳۸۴
محل انتشار: سمپوزیوم برآورد عدم قطعیت در مهندسی سد
تعداد صفحات: ۱۰
M. WIELAND – Electrowatt-Ekono Ltd. (Jaakko Pöyry Group), Zurich, Switzerland
S. MALLA – Electrowatt-Ekono Ltd. (Jaakko Pöyry Group), Zurich, Switzerland
J. SPEERLI – University of Applied Sciences, Switzerland (formerly Electrowatt-Ekono Ltd)
D. OSTANEVICS – Latvenergo, State Joint Stock Company, Latvia
Risk analysis is a systematic tool that allows the comparison of risks from different types of hazards.It facilitates the identification of the weak elements of a complex dam system and the hazards that mainly contribute to the risk. Thus, the vulnerability of a dam can be reduced by strengthening these weak elements. In general, the basic threats to hydropower plants are as follows: • Abnormal behavior such as joint leakage, settlements, seepage and erosion at the concretesoil interface, etc., • Mass movements such as landslide, rock fall, ice fall, avalanche, • Flood, • Earthquake, • Sabotage, and • Acts of war. The first three threats develop relatively slowly and precautionary measures can be taken, whereas the last three threats are unpredictable. The last two cannot be treated by conventional statistical/probability analyses and are not considered in the quantitative risk analysis. All these threats have large uncertainties with respect to occurrence and the magnitude of an event. To cope with unpredictable man-made risks, emergency planning and water alarm systems are needed. The risk in the potential flood plain can be reduced substantially by means of non-structural measures, such as a water alarm system and land use planning, which reduce the consequences of a flood wave. Water alarm systems form the key element for warning the population in the flood plain. By issuing a timely warning, practically all people can be saved. Emergency planning is a key element in the comprehensive safety concept for dams, which includes (i) Structural safety, (ii) Dam safety monitoring, (iii) Dam operation and maintenance, and (iv) Emergency planning. The main results of the detailed risk analysis of the Daugava Cascade and the Plavinas HPP in Latvia are discussed in this paper.