Stability analyses for levees on deep-mixed shear walls

The deep-mixing method can increase the strength of soft ground, and thereby improve the stability of earthen levees. Additional benefits are that deep-mixing support can accelerate construction and protect adjacent facilities from deformations that would otherwise be induced by the new embankment loads. Continuous shear walls located under the embankment side slopes and oriented perpendicular to the embankment centreline are more efficient for stability than isolated columns because shear walls are not subject to the same type of bending failure that isolated columns can experience. Even when continuous shear walls are used, stability analyses must consider multiple modes of failure, such as composite shearing, rotation of the deep-mixed zone, shearing on vertical planes along column overlaps, extrusion between shear walls, crushing of the deep-mixed ground at the toe of the deep-mixed zone and global instability. This paper presents simplified analysis methods for stability of earthen levees supported on deep-mixed shear walls.