LARGE SCALE PHYSICAL MODEL TO INVESTIGATE THE MECHANICS OF EMBANKMENT EROSION DURING OVERTOPPING FLOW | ||||
| ERJ. Engineering Research Journal | ||||
| Article 8, Volume 36, Issue 3, July 2013, Page 287-302 PDF (4.48 MB) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/erjm.2013.67430 | ||||
 View on SCiNiTO | ||||
| Authors | ||||
| Entesar A. S. EL-Ghorab; Ahmed Fahmy; M. Fodda | ||||
| Hydraulic Research Institute, National Water Research Centre | ||||
| Abstract | ||||
This paper presents the results of large scale physical model embankment failure experiments. The model simulates the failure by overtopping of three embankments that are varying in dimensions and soil type. The soil is either homogeneous pure sand or mixture of sand, silt and clay. A new measuring technique consists of the labeled rod bridge; grids lined and captured instantaneous pictures are utilized to monitor the failure. It was used to analyze the morphological evolution during embankment failure. The flow pattern and progressive failure of embankment overtopping were investigated. The results showed four types of phenomenon during embankment failure: erosion; erosion with sliding; erosion with mass failure and head cut migration. The results revealed that the recorded time to reach the full breach failure in case of mixture materials (sand, silt and clay) is seven times that with pure sand. Also, reducing the embankment height to 50% (0.9m), led to increase the time to peak discharge 8.4 times that of large one (1.8m). Adding 15% clay to pure sand changes soil characteristics to (c and o) soil which makes soil to have a critical vertical cut height. Set of dimensionless regression equations are developed by using the experimental data. In conclusion, types of embankment failure are defined. Adding a percentage of clay (15%) to the pure sand led to the maximum remain vertical cut height of about 50% of the calculated critical vertical cut height (Z). Bearing in mind the limited number of large scale testes for embankment breach in literatures, the set of data could be used for calibration of mathematical breach models and provides a reference for the flood risk management of embankments. | ||||
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