Consolidation Settlement of Bridge Approach Foundation

Excessive settlement of bridge-approach pavements creates problems for both road users and transportation agencies responsible for road maintenance. An important contributing factor to this settlement is the consolidation of foundation soil. A procedure based on the nonlinear finite-element method (FEM), including infinite elements, is developed to analyze the consolidation settlement of embankment foundation at the bridge approach. Biot's theory of three-dimensional consolidation, as proposed by Sandhu and Wilson, is used in the development. Nonlinear behavior of the soil skeleton is represented by the modified Cam-clay model. A plane-strain infinite-element algorithm is developed. The semi-infinite domain is divided into two regions. The near field is discretized by using the eight-noded isoparametric elements, while the far field is discretized by using the infinite elements developed. The interpolation functions for the infinite element are chosen based on the far-field behavior of a homogeneous porous elastic half plane. The analysis procedure is applied to study the time-settlement history and pore-pressure dissipation characteristics of a bridge-approach site in Oklahoma.