| Popis: |
In July 1997 the Morava river basin was hit by destructive floods which cannot be compared with any disaster in this region since 1900. The centenary water-level was exceeded and, due to unfavourable circumstances, the river was in spate for almost three weeks. In several places the flood protection dams along the river were broken or poured over and many towns and villages were flooded. After the first urgent reconstructions, the question of stability of all flood protection dams along the river had to be solved. The total length of the dams along the Morava river exceeds 400 km. The dams were originally built of local materials by farmers settled along the river in the beginning of the 20th century. Neither the composition of the dams, nor the method of foundation and soil compaction are known. At first, Povodi Moravy a.s., the administrator of the Morava river basin, decided to investigate the most exposed sections of the dams, i. e. the places where the dams were overflowed and where leakages and outflows appeared. It is obvious, that for the stability evaluation of the dams, not only the dam itself and the underlying beds, but also the foreground to a certain distance from the river had to be investigated. Non-destructive geophysical methods were chosen for the first stage of the investigation as a quick, relatively cheap and reliable investigation tool. Classical engineering-geological methods, such as borehole drilling, sampling and laboratory analyses will follow in next stages to make the interpretation more accurate and to clarify some disputable results. |
