Soil structure interaction of piled structures adjacent to surcharge loads

Full-height bridge abutments or piers supported on foundations piled through soft clay are frequently exposed to lateral interaction effects associated with soil movement relative to the structure. In the specific case of a full-height piled bridge abutment, as clay is displaced laterally beneath the embankment, shear stress will be generated on the interface with the fill material. This effect contributes to stability of the foundation soil against bearing capacity failure at the expense of increasing lateral pressure in the lower regions of the fill, and therefore increasing abutment wall loading. The results of a series of centrifuge tests have demonstrated the potential significance of this mechanism, both in the undrained case, and as consolidation of the clay proceeds. 2D finite element analyses are being undertaken to determine the sensitivity of this interaction to parameters such as: stiffness of the fill material, stiffness of the abutment response to lateral loading, and properties of the foundation soil (eg anisotropy of strength, stiffness and the presence of a stiffer crust). -from Author