The built environment serves as a dynamic interface through which human society and the ecosystem interact and influence each other. Understanding this interdependence is a key to understanding sustainability as it applies to civil engineering. There is a growing consensus that delivering a sustainable built environment starts with incorporating sustainability thoughts at the planning and design stages of an infrastructure construction project. Geotechnical engineering can significantly influence the sustainability of infrastructure development because of its early position in the construction process. In this paper, the scope of geotechnical engineering towards sustainable development of civil infrastructure is reviewed. The philosophies and definitions of sustainability as applicable to geotechnical engineering are discussed. A comprehensive review of the research and case studies performed in geotechnical engineering, in relation to sustainable development, is presented in an effort to outline the scope and goals of sustainable geotechnical engineering.

An analysis is developed to calculate the response of laterally loaded piles in multilayered elastic media. The displacement fields in the analysis are taken to be the products of independent functions that vary in the vertical, radial and circumferential directions. The governing differential equations for the pile deflections in different soil layers are obtained using the principle of minimum potential energy. Solutions for pile deflection are obtained analytically, whereas those for soil displacements are obtained using the one-dimensional finite difference method. The input parameters needed for the analysis are the pile geometry, the soil profile, and the elastic constants of the soil and pile. The method produces results with accuracy comparable with that of a three-dimensional finite element analysis but requires much less computation time. The analysis can be extended to account for soil non-linearity.

Traditionally, analyses developed for circular piles have also been used for rectangular piles by replacing in calculations the rectangular pile with a circular pile of equivalent area. In this paper, we present a settlement analysis that applies to piles with either rectangular or circular cross sections installed in multilayered soil deposits. The analysis follows from the solution of the differential equations governing the displacements of the pile-soil system obtained using variational principles. The input parameters needed for the analysis are the pile geometry and the elastic constants of the soil and pile. Pile displacements and vertical soil displacements calculated using this analysis match well those from finite-element analysis. A parametric study highlights some important insights for rectangular and circular piles in multilayered soil. A user-friendly spreadsheet program (ALPAXL) was developed to facilitate the use of the analysis. Examples illustrate the use of the analysis in design.

Laterally loaded piles are analyzed using the Fourier FEM. The analysis is performed for piles embedded in single-layer elastic soil with constant and linearly varying modulus and in two-layer elastic soil with constant modulus within each layer. The pile responses were observed to be functions of the relative stiffness of pile and soil, and of the pile slenderness ratio. Based on the analysis, equations describing pile head deflection, rotation, and maximum bending moment are proposed for flexible long piles and stubby rigid piles. These design equations are developed after plotting the pile responses as functions of pile-soil stiffness ratio and pile slenderness ratio. These plots can also be used as design charts. Design examples illustrating the use of the analysis are provided.