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A new method of analysis of rigid monopiles and poles based on the principle of virtual work is developed. The analysis considers three-dimensional interaction between the rigid pile and surrounding soil, and quickly produces pile response while maintaining accuracy comparable with that obtained from equivalent finite element analysis. Using this method, a systematic parametric study is performed to investigate the response of rigid piles in soil profiles where properties change either continuously or discretely with depth. Equations are developed based on the parametric study, which can be used to calculate pile head displacement and rotation. Numerical examples are provided that illustrate the use of the method. Key words: rigid pile, monopile, pole, wind energy, variational calculus, analytical solution. Une nouvelle methode d'analyse de monopieux et de poteaux rigides fondes sur le principe de travail virtuel est developpee. L'analyse prend en compte l'interaction tridimensionnelle entre les pieux rigides et le sol environnant et produit rapidement une reponse de pieux et maintien l'exactitude comparable a celui resultant de l'analyse par elements finis equivalent. En utilisant cette methode, une etude parametrique systematique est effectuee pour etudier la reponse des pieux rigides dans les profils de sols oU les proprietes changent continuellement ou discretement avec la profondeur. Des equations sont elaborees en fonction de l'etude parametrique, qui peut etre utilisee pour calculer le deplacement de tete de pieu et la rotation. Des exemples numeriques sont fournis qui illustrent l'utilisation de la methode. [Traduit par la Redaction] Mots-cles: pieux rigide, monopieux, poteau, energie eolienne, calcul variationnel, solution analytique., Introduction Monopiles are large-diameter hollow cylindrical piles used as foundations for about 76% of wind turbines installed around the world (EWEA 2014). In offshore regions, these piles are usually 4-6 [...]

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. Key words: sustainability, geosustainability, resilience, reliability, geosystems. L'environnement bati sert d'interface dynamique a travers laquelle la societe humaine et l'ecosysteme interagissent et s'influencent l'un et autre. La comprehension de cette interdependance est la cle de la comprehension de la durabilite telle qu'appliquee en genie civil. Il y a un consensus grandissant qui considere qu'un environnement bati durable commence par l'integration de la pensee durable aux etapes de planification et de conception d'un projet de construction d'infrastructure. Le genie geotechnique peut influencer significativement la durabilite d'un developpement d'infrastructure en raison de la position en debut du processus de construction. Dans cet article, une revue de l'apport du genie geotechnique vers le developpement durable d'infrastructures civiles est presentee. Les philosophies et definitions de la durabilite applicables au genie geotechnique sont discutees. Une revue detaillee de la recherche et d'etudes de cas realises en genie geotechnique et relies au developpement durable est presentee afin de definir les objectifs et buts du genie geotechnique durable. [Traduit par la Redaction] Mots-cles: durabilite, geodurabilite, resilience, fiabilite, geosystemes., Introduction Sustainability of a system is its ability to survive and retain its functionality over time. In very simple terms, sustainability deals with the supplies (capacities) and demands (loads) in [...]

The paper presents a framework for analysis of beams interacting with nonlinear‐poroelastic, layered continuums (e.g., clayey soils) when subjected to time‐dependent loads. The poroelastic layered continuum is characterized by a nonlinear‐elastic constitutive relationship that relates the secant shear modulus to the induced shear strain. The Biot's theory of consolidation is combined with a dynamic beam‐continuum interaction model to develop the analysis. The vertical consolidation settlement of the beam and the excess pore pressure in the porous continuum are assumed to be products of separable functions, and the extended Hamilton's principle of least action is applied to obtain the differential equations governing the inertial consolidation motion of the beam‐continuum system and the dissipation of excess pore pressure. An iterative numerical algorithm is used to solve these coupled differential equations following one‐dimensional finite element analysis in which the implicit Wilson‐Θ time integration scheme is used to obtain the time history of beam and continuum responses. The novelty of the framework is that it rigorously takes into account the nonlinear poroelastic soil‐structure interaction within a dynamic time‐integration framework with minimal computational resources. The characteristics of this newly developed model are illustrated through examples. [ABSTRACT FROM AUTHOR]

Geotechnical constructions involve consumption of a vast amount of non-renewable natural resources and energy- and carbon dioxide-intensive materials (e.g. cement and steel) that contribute significantly to global warming and climate change. This paper uses drilled shafts as an example to illustrate the importance of environmental impact assessment in the design phase of foundations. Life-cycle assessment (LCA) is used to quantify the environmental impacts of construction of single drilled shafts and groups embedded in sandy soil profiles. Parametric studies are conducted to investigate the effects of soil properties, design parameters and hauling distances of construction materials and equipment on the environmental impacts of single drilled shafts. For pile groups, different configurations, applied load, centre-to-centre spacing and thickness of pile cap are considered in the parametric study. The global warming impact and human toxicity of a typical drilled shaft are found to be 39 and 486% of annual world impact per person, respectively. Based on the study, charts and tables are developed that may be used for quick estimation of the global warming impact of drilled shafts without the use of specialised LCA software programs. [ABSTRACT FROM AUTHOR]

The load-settlement behaviour of piled raft foundations (PRFs) resting on sand subjected to vertical uniformly distributed load is studied using three-dimensional elasto-plastic finite element (FE) analyses. The unified Clay and Sand Model (CASM), based on the critical state soil mechanics, is used as the soil constitutive model. In the present study, 38 rectangular, strip, and circular raft connected to different pile configurations resting on four different types of sands in their loose, medium, and dense states are considered. The accuracy of the finite element analysis is confirmed through verification and validation with other numerical and experimental studies. A detailed parametric study is conducted, which includes soil elastic and critical state parameters as well as different dimensions of PRFs. A guideline chart is provided, which will be helpful for a design practitioner to choose the suitable PRF configurations considering serviceability limit states of safety and economical design aspect. This flow chart is based on (i) combined effects of various parameters on PRF load settlement behaviour, (ii) load sharing between the raft and the pile groups, and (iii) a preliminary cost analysis. [ABSTRACT FROM AUTHOR]

Short stubby piles like monopiles and large diameter drilled shafts undergo rigid body translation and rotation when subjected to a lateral force and/or a moment at the head. A method of analysis for these piles embedded in multi-layered elastic soil is developed using the variational principles of mechanics. Using this analysis, the soil resistance against pile movement can be rigorously related to the soil elastic constants, and the pile head displacement and rotation can be quickly calculated. The equilibrium equations for pile and soil displacements are obtained using the principle of virtual work and solved using an iterative algorithm. Pile responses obtained from the analysis match well with those obtained from three-dimensional finite element analyses in which the same inputs of loads, geometry, and material properties are given. Based on the new analysis, fitted equations for soil resistance parameters are developed, which can be used to directly calculate the pile head displacement and rotation without the use of the iterative algorithm. Numerical examples are provided that demonstrate how the method can be used to analyse practical problems. [ABSTRACT FROM AUTHOR]