Rotation of Cantilever Sheet Pile Walls

Cantilever sheet pile walls are used routinely to retain medium heights of earth in geotechnical practice. Earth pressures developed on either side of the sheet pile wall ensure its moment and force equilibrium. Cantilever sheet pile walls suffer rotation about a pivot point close to the base and generate passive and active earth pressures. Earlier methods to determine the pivot point either use iterative procedures or rely on centrifuge data or finite element analyses. In this paper a new method based on minimization of the moment ratio is proposed to determine the location of the pivot point. This method is applicable to both cohesionless and cohesive backfills. Consideration of moment equilibrium is sufficient to determine the pivot point and force equilibrium is automatically satisfied. The location of the pivot point obtained by this approach compared satisfactorily with the centrifuge and laboratory test data. The shear strength demand computed for these tests could predict when sheet pile walls became unstable. Finally the shear strength demand was linked to the shear strains and hence to the wall deflections that compare satisfactorily with experimental wall deflections.