Determination of Critical Head in Soil Piping

Abstract

One of the main mechanisms of failure of levees is a phenomenon called ''piping,'' which generally begins with the formation of a sand boil at the leeward side of the levee, and has been frequently observed to proceed upstream along the base of the levee through a slit formation. The issue of most important concern is to estimate the critical head that could promote the occurrence of piping. Considering the flow through porous media and coupling it with Bernoulli's equation and a critical tractive stress condition, a model is developed for the critical head. Using appropriate transformations, the proposed model takes on a form which supports Bligh's empirical findings. Another model based on critical velocity is also developed to estimate the critical head. The functional form of these two models is evaluated using the critical head versus porosity data from a number of laboratory studies conducted in the Netherlands. These models were found to perform better than did Terzaghi's model.

Numerical Analysis of the Erosion and the Transport of Fine Particles within Soils Leading to the Piping Phenomenon

“…Boiling is the failure of a soil skeleton induced by an intergranular seepage force greater than the resistible force of the soil mass due to its weight. The studies on boiling have been focused on the determination of the critical hydraulic head or the gradient (e.g., Meyer et al, 1994;Ojha et al, 2003). Internal erosion is the detachment ofˆne particles from the soil fabric due to the seepage ‰ow and the transport of these particles out of the soil mass, which increases porosity and leads to piping (e.g., Khilar et al, 1985;Reddi et al, 2000;Wan and Fell, 2004).…”

Effectiveness of distributed temperature measurements for early detection of piping in river embankments

“…Many other experimental and theoretical studies followed across the years (e.g. WES, 1956;De Wit et al, 1981;Weijers and Sellmeijer, 1993;MullerKirchenbauer et al, 1993;Schmertmann, 2000;Ojha and Singh, 2003;Sellmeijer et al, 2011;. Later studies show that researchers are still investigating the subject to improve the theoretical model (e.g.…”

Seepage Piping Evolution Characteristics in Bimsoils -An Experimental Study

“…Although the bimsoil piping phenomenon has been studied by several scholars [37][38][39][40][41][42][43][44], the study of the piping evolution process of bimsoil in laboratory test is mostly based on conventional penetration testing (e.g., constant head test) [37,38], and it is difficult to precisely control the seepage hydraulic pressure and hydraulic gradient. In addition, although field experiments can obtain macroscopic piping characteristics of bimsoil, it is impossible to study the change of the permeability coefficient with hydraulic gradient [41][42][43].…”