Theoretical Formula of the Critical Hydraulic Condition of Suffusion Initiation

Some embankment dam distress or failures are associated with suffusion under seepage forces, and the onset of suffusion occurring within an embankment core or the foundation of a dam is governed by the hydro-mechanical conditions within the soil and initiated where seepage force exceeds a critical threshold. The main objective of this study is to discuss the critical hydro-mechanical conditions of suffusion initiation. Theoretical formulas and models previously proposed for determining the critical hydraulic gradient of suffusion initiation are summarized and compared first, as well as their limitations, and then a new equation based on the seepage force concept is proposed. A case study is conducted to verify the new equations, and comparison with the experimental result indicates that the new proposed equation may be more reasonable than others.