SSP Design

Current design methods for retaining walls do not provide for rigorous theoretical analysis due to the complexity of the problem. The methods that have been developed to overcome this, with the exception of finite element modeling techniques, introduce empirical or empirically based factors that enable an acceptable solution to the problem to be found. As a result, no theoretically correct solution can be achieved and a large number of different approaches to this problem have been devised.

A steel sheet pile retaining wall has a significant portion of its structure embedded in the soil and a very complex soil/structure interaction exists as the soil not only loads the upper parts of the wall but also provides support to the embedded portion. The design of a retaining structure using currently available techniques requires the performance of two sets of calculations, one to determine the geometry of the structure to achieve equilibrium under the design conditions, the other to determine the structural requirements of the wall to resist bending moments and shear forces determined from the equilibrium calculations. The selected design conditions should be sufficiently severe and varied so that all reasonable situations which may occur during the life of the structure are taken into account.

Designers should not overlook the possibility of global failure resulting from deep-seated slip failure of the soil and ensure that the slip plane passing through the pile toe is not critical. Similarly, anchor walls should be located outside potential slip planes.