Review Of Dam-break Research Of Earth-rock Dam Combining With Dam Safety Management
Developmental characteristics of dam-break research on earth-rock dam were reviewed and nowadays researchers emphasized corporation and paid more attention to quantitative description, multiple processes coupling and system integration in research. Combining with most concerned problems in dam safety management (DSM), achievements were reviewed in three fields: causal factors of disasters, dam-break process and flood propagation. In order to perfect a DSM system, researches on variations of dam material properties and corresponding effect in dam-break process, scale effect, similarity criteria of dam-break process and uncertainty analysis of common used models should be enhanced. An essay writer is a person whose job is to create articles and these Dam related information will be highlighted in an the form of essay.
1. Introduction
Dam failure disasters usually cause huge loss of lives and destructions of properties and environment. For example, the 1963 failure of Vajont dam in Italy caused 2600 deaths, the 1976 failure of Teton dam in America caused hundred deaths and economic loss about 1 billion dollars, and the 1993 failure of Gouhou dam in China caused 300 deaths. The statistical analysis of 534 dam failures from 43 countries before 1974 indicated that earth-rock dam failures accounted for the largest proportion of all failures and included 49% caused by overtopping, 28% seepage in dam body and 29% seepage in foundation. There are about 3498 dam failures in China between 1954 and 2006, 90% of which are earth dam, especially homogeneous earth dam which accounts for 85% of all these failures. An online essay writing service offers an original dam safety content in essay format crafted by our professional essay writers.
Reasons for dam failures can be divided into two types: natural causes and human attributes. The former includes: 1, external causes, such as heavy rains, hurricanes, earthquakes, etc.; 2, internal causes, aging of materials, dam body defects, foundation defects and so on. Human attributes include: 1, global climate warming, which enhanced atmospheric circulation and then extremely rain increased, caused glacier retreat and glacial lake were formed and the threats of dam break increased; 2, terrorist attacks or wars; 3, major construction projects increased the potential threats of dam break, for example, there were about 85 thousand reservoirs including 30 thousand in danger, as well as various embankments about 2500 thousand kilometers long in the flood control system of 7 biggest rivers in China by 2009. Dam failure disasters and potential threats highlight the need for forecasting, prevention and reduction of dam-break disasters. Establishment and perfection of a modern DSM system is imperative. Modern DSM needs sound regulations and guidance, advanced safety management mode and related technologies (dam-break process modeling, flood propagation modeling, risk assessment technologies, etc.), all of which are established based on the achievements of dam-break research. In other words, the establishment and perfection of modern DSM system depends on the development of dam-break research. Dam-break studies of earth-rock dams as theoretical supports for DSM were reviewed and discussed in this paper. The writer assigned to write my essay request related to dam safety information is qualified to the same academic level or higher than your writing requirements.
2. History of dam-break research
Characteristics and contents of dam-break research have been changed with research background since studies of dam-break problems were started in 1850s in France. Based on different characteristics and contents of dam-break research at different times, three periods are divided: the first period (from 1850 to 1950), the second period (between 1950 and 1990) and the third period (from 1990 until now). For there was no computer before 1948, dam-break studies in the first period were mainly focused on theoretical solutions for dam-break wave problems and related physical model tests. For example, Ritter neglected the bed shear friction and riverbed topography and obtained a simplified solution for the situation of rectangular instantaneous total collapse with dry riverbed in the downstream for the first time by using the characteristic form of Saint-Venant equations in 1892.
Ignoring the riverbed topography and friction, Stocker divided the flow patterns of dam site into three types: continuous wave flow, critical flow and discontinuous wave flow and extend Ritter solution to the wet-bed situation [4]. Researches on analytical solutions for dam-break wave problem tended to be mature nowadays but only limited in some special cases [5-8]. Since large amount of dams were constructed in 1950s, causal factors of dam-break disasters and threats of dam-break flood on the downstream cities or towns had been paid much attention to during the second research period. For example, laboratory experimental tests and field tests of earth-rock dam were carried out by US and Austria to study the casual factors of dam-break disasters and timing scale for dambreak process [5]. For the design of different projects in China, dam-break process were modeled to investigate dam-break peak discharge, outflow hydrograph and flood inundation by several research institutions [5, 9-10]. As computer had been invented and used in dam-break research in this period, many modeling technologies had been developed and lots of dam-break mathematical models had been built, such as Cristofano model, HW (Harris-Wagner), DAMBRK, BREACH, BEED, SMPDBK, BRDAM, MIKE, DHI and so on. Hire a reliable online essay writer who will create an original paper related to dam safety information and deliver it on time.
3. Theoretical supports for Modern DSM
Modern DSM system includes regulations and guidance system, risk analysis system, safety monitor system, danger control and reinforcement system, early warning system, emergency plan system. Regulations and guidance system provide guidance for other systems. Just like aerial photography, remote sensing and GIS technology providing strong technological supports for DSM system, dam-break researches offer theoretical supports for it. For example, results of researches on causal factors of dambreak disasters make safety monitor system more targeted and probability calculation of dam-break disaster in risk analysis more rationality; emergency treatment depends on the understanding of dambreak process and the results from flood propagation modeling. As following, achievements in dam-break researches are reviewed and discussed as theoretical supports for DSM in three fields: causal factors of dam-break disaster and catastrophe conditions, dam break process, and flood propagation. The writer appointed to write my essay for me task of dam related information is able to the same scholastic level or higher than your composing requirements.