Piping Slopes, Earth Dams, Foundations & Pavements Engineering Essay

Investigating Piping Failures
Student's Name
Institution Affiliation
Course Name + Code
Professor
Submission Date
PIPING FAILURE
Piping, also known as internal erosion is a process that occurs inside the dam whenever the seepage flow starts eroding embankment materials out of and away from the dam. The water that seeps through will carry with itself soil particles, which in turn erodes soil or soft rock moving them downstream. This process will tend to accelerate as the larger opening or pipe allows for increase seepage flow. If left unattended the seepage flow will progress the internal erosion having it out of control. With the internal pipe becoming large, the embankment structure above it will collapse resulting to a failure in of the dam's embankment leading to the fatal release of stored water which may cause severe damage to property and loss of life. Backward erosion piping is an internal erosion mechanism during which shallow pipes are formed in the direction opposite to the flow underneath water-retaining structures as a result of the gradual removal of sandy material by the action of water (Van Beek, 2015).
Internal erosion or piping process occurs in four major phases which is the initiation of erosion process, progression to form a pipe, surface instability and finally the initiation process of a breach. The Teton Dam, located in Idaho failed by piping in 1978. Teton Dam was a zoned earth dam with a low-permeability central core. It rose 405 feet above its foundation and 305 feet above the riverbed and was about 3,000 feet long. It would have formed a 288,250 acre-foot reservoir. The spillway was a gated chute structure on the right abutment (Barnes, 1992). The dam was located in a region with a foundation that had highly porous materials. Designers of the dam did not give proper treatment to the foundation materials, and this was not implemented. The dam’s geological specifications were not taken into consideration during construction. The design and construction engineers did not agree on specific procedures to carry out an earlier feasibility test, a lapse that came as a result of improper communication. The dam foundation was therefore inadequately treated, and it was also not up to par with standard specifications of constructing a dam as big as this one. The constructed trench that was supposed to be key in preventing seepage through the dam’s embankment, its slush grouting was not sufficien...