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Backward erosion piping takes place when the phreatic line cuts the downstream face of the dam and seepage pressure is high.

Backward erosion piping takes place when the phreatic line cuts the downstream face of the dam and seepage pressure is high. Correct Answer True

Backward erosion piping is an important failure mechanism for water-retaining structure and local disruption of the downstream top layer leads to concentrated seepage flow. This results in erosion that continues in the upward direction. It is ensured that the phreatic lines never touch the downstream side of the earth dam to avoid failure.

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