Numerical Study on the Cavity-Induced Piping Failure of Embankment

Cavities are frequently found beneath conduits on pile
foundations in old embankments. Cavity reduces seepage length
significantly and consequently causes piping failure of embankments.
Case studies of embankment failures indicate that the relative
settlement between ground and pile supported-concrete conduit was
the main reason of the cavity. In this paper, an attempt to simulate the
cavity-induced piping failure mechanism was made using finite
element numerical method. Piping potential is examined by carrying
out parametric study for influencing factors such as cavity length,
water level, and flow conditions. The concentration of hydraulic
gradient adjacent to cavity was found. It is found that the hydraulic
gradient close to the cavity exceeds considerably the critical hydraulic
gradient causing piping. Piping failure potential due to the existence of
cavity is evaluated and contour map for the potential risk of an
embankment for piping failure is proposed.

Authors:

• H. J. Kim
• G. C. Park
• K. C. Kim
• J. H. Shin

Keywords:

• Cavity
• Embankment
• Hydraulic gradient
• Piping.

References:

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test,” Master Thesis (in Korean), 2014.
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safety estimation of box-culvert in levee,” Journal of Korea Water
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[5] K. H. Kim, G. C. Park, D. R. Kim, J. H. Shin, “Evaluation of piping
stability under dynamic conditions,” in Proc. 8th International
Symposium on Underground Construction in Soft Ground, Seoul, 2014,
pp. 91-95.