科研之友
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摘要
Failures of earthen flood protection structures cause enormous material loss. Despite this, in the majority these are structures that were built decades ago. As an example, in Poland, the time of operation of approximately three quarters of existing levees and embankments is over 40 years. A similar situation exists. in many other European countries.. In the period. 1998-2009 the economic losses caused by floods amounted to over 60 thousand million Euro. This accounts for approximately one third of the. total losses caused by environmental factors. Ruptures of embankments or levees occur as a result of long-lasting elevated water levels in rivers, and such events are always preceded by changes in their internal structure. Such changes cannot be detected from the. outside. This paper presents a new method, never used before, for the determination of changes in the internal structure of the body of a levee. The dynamics of the displacements is described by means of new mathematical formulae. The input data necessary for their application include the dynamics of changes in. the value. of volumetric moisture that is measured with a freely selected short time step by means of the time-domain-reflectrometry. technique. The formulae were created on the basis of. hitherto unnoticed and uninterpreted. drops in moisture a moment before and a moment after the saturation of inner spaces of the levee body. The results obtained from calculations were compared with data from measurements on a physical model of a levee. The settlement values calculated using. the method proposed are convergent with those of the true settlement. The maximum relative error was as low as 19%. The method proposed permits the location of changes in the internal structure of a levee before its rupture. Its application is the main component of a. system of early warning against floods.
- 出版日期2017-3
