مقاله انگلیسی رایگان در مورد درجه خطر عمل مرحله ای مخزن سد خاکی در فصل سیل – الزویر 2018

According to statistics from the National Bureau of Statistics of the People’s Republic of China (MWR and NBS, 2013), there are currently more than 98000 reservoirs in China, with a total capacity of over 900 billion cubic meters. Of these reservoirs dams, up to 90% are embankment dams. However, due to historical reasons (e.g., inadequate survey and design, poor construction quality, and improper management), more than 36% of these dams and reservoirs are in dangerous conditions, with various degrees of risk, which not only limit the use of the reservoirs and maximization of economic benefits, but may also cause potentially catastrophic consequences like life loss and property damage if they are wrecked. For these reasons, dam safety and danger condition evaluation are of the utmost importance (Hartford and Baecher, 2004; Jiang and Fan, 2008). Moreover, according to the International Commission on Large Dams (ICOLD, 1973), nearly 50% of earth dam disasters in China and one-third in the world are caused by flood overtopping, seepage, and piping, and other causes make up the rest (Hege, 1997; Jin, 2008). In principle, an earth dam is considered to be destroyed after suffering flood overtopping, which might lead to unexpected consequences. Therefore, it is important and urgent to improve danger degree analysis and assessment, thus offering a scientific basis and reference for risk management and security decision-making. In the case of modification of dangerous dams, including repairs and reconstruction, economic feasibility and social safety goals need to be addressed. When evaluating the priority of earth dam rehabilitation, it is necessary to estimate the danger degree of these dams and reservoirs and sort them, in order to determine the urgency of reinforcement, which will contribute to reasonable allocation of limited resources. Thus, danger degree evaluation is a potentially useful approach. On the other hand, a flood-water resources utilization strategy with higher standards has been put forward to meet the requirements of rapid industrial and agricultural development. Fortunately, reservoirs are one of the most efficient types of infrastructure for integrated water resources development and management, and flood-limiting water level (FLWL) during the flood season is an important parameter in reservoir operation and the key to coordinating the contradiction between flood risk and reservoir benefit (Eum and Simonovic, 2010; Yun and Singh, 2008). In addition, an annual fixed FLWL for the whole flood season may reduce electricity generation, because of the lower water level. In this case, water shortage may occur when the flood season is delayed or ends prematurely, which prevents the reservoir from refilling to the normal water level by the end of the flood season. Sub-season flooding and the corresponding FLWL for flood control have been proposed to coordinate flood control and water resources utilization. When the highest water level in front of the dam exceeds the elevation of the dam crest, it will lead to earth dam overtopping and cause earth dam failure. Higher standards for flood water resources utilization seek a more suitable scheduling solution for reservoir optimal operation. The scheduling solution with optimal utilization of water resources, including flood resources that could otherwise lead to disasters in some rainy regions, cannot excess a dam’s flood control risk. Therefore, research on the danger degree for flood control risk of earth dam reservoir staged operation is a key step for solidification or reconstruction for dangerous reservoirs, as well as an effective way to flood water resources utilization.