Deep foundation

A deep foundation is a type of foundation that transfers building loads to the earth farther down from the surface than a shallow foundation does to a subsurface layer or a range of depths. A pile or piling is a vertical structural element of a deep foundation, driven or drilled deep into the ground at the building site. There are many reasons that a geotechnical engineer would recommend a deep foundation over a shallow foundation, such as for a skyscraper. Some of the common reasons are very large design loads, a poor soil at shallow depth, or site constraints like property lines. There are different terms used to describe different types of deep foundations including the pile (which is analogous to a pole), the pier (which is analogous to a column), drilled shafts, and caissons. Piles are generally driven into the ground in situ; other deep foundations are typically put in place using excavation and drilling. The naming conventions may vary between engineering disciplines and

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Selected Aspects Of Designing Deep Excavations

Rafal Filip Obrzud

This paper analyzes two approaches to serviceability limit state (SLS) verification for the deep excavation boundary value problem. The verification is carried out by means of the finite element (FE) method with the aid of the commercial program ZSoil v2014. In numerical simulations, deep excavation in non-cohesive soil is supported with a diaphragm wall. In the first approach, the diaphragm wall is modeled with the Hookean material assuming reduced average stiffness and possible concrete cracking. The second approach is divided into two stages. In the first stage, the wall is modeled by defining its stiffness with the highest nominal Young's modulus. The modulus makes it possible to find design bending moments which are used to compute the minimal design cross-section reinforcement for the retaining structure. The computed reinforcement is then used in a non-linear structural analysis which is viewed as the "actual" SLS verification. In the second part, the paper examines the same boundary value problem assuming that the excavation takes place in quasi-impermeable cohesive soils, which are modeled with the Hardening Soil model. This example demonstrates the consequences of applying the steady-state type analysis for an intrinsically time-dependent problem. The results of this analysis are compared to the results from the consolidation-type analysis, which are considered as a reference. For both analysis types, the two-phase formulation for partially-saturated medium, after Aubry and Ozanam, is used to describe the interaction between the soil skeleton and pore water pressure.

Walter de Gruyter GmbH2016

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Effect of groundwater flow on the THM behavior of an energy pile

Mélanie Baehler, Fabrice Dupray, Lyesse Laloui

Bridges are one of the road structures that are most exposed to icing, a problem that is widely dealt with through salting, a technique that reduce the lifespan of the bridge. Seasonal storage of solar heat energy captured directly through the asphalt layer is a promising solution that can be achieved cost-effectively only if a necessary geostructure is used as heat-exchanger. Bridge piles and abutments are founded on piles that can be used as heat exchangers. Seasonal storage and natural thermal reload are two possible solutions for the operation of such a system, depending on local conditions. In particular, the presence of groundwater flow is thought to be a significant factor in such a design and is taken into account. The study aims at determining the geotechnical and energy design parameters through thermo-hydro-mechanical numerical simulations. A single heat-exchanger pile is taken as an example in this study. Given the presence of water flow, a three-dimensional FEM simulation needs to be carried out. The soil is described as a thermo-elastic porous medium, and various groundwater flow scenarios are studied. The capture of energy and the needs for deicing are based on the few existing structures that use other means of energy exchange with the ground. The article proposes an overview of all coupled phenomena, between thermal, hydraulic and mechanical aspects. Results show that only specific sites can be considered for using heat-exchanger piles for deicing bridges, but that the efficiency of the solution in those sites is high. Possible stability problems, in terms of foundation and structure are also considered, such as vertical displacements due to the dual use of the foundation piles.

Taylor & Francis Group2013

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Data compression to define information content of hydrological time series

Marc Parlange, Nicolaas Cornelis van de Giesen, Steven Vincent Weijs

When inferring models from hydrological data or calibrating hydrological models, we are interested in the information content of those data to quantify how much can potentially be learned from them. In this work we take a perspective from (algorithmic) information theory, (A)IT, to discuss some underlying issues regarding this question. In the information-theoretical framework, there is a strong link between information content and data compression. We exploit this by using data compression performance as a time series analysis tool and highlight the analogy to information content, prediction and learning (understanding is compression). The analysis is performed on time series of a set of catchments. We discuss both the deeper foundation from algorithmic information theory, some practical results and the inherent difficulties in answering the following question: "How much information is contained in this data set?". The conclusion is that the answer to this question can only be given once the following counter-questions have been answered: (1) information about which unknown quantities? and (2) what is your current state of knowledge/beliefs about those quantities? Quantifying information content of hydrological data is closely linked to the question of separating aleatoric and epistemic uncertainty and quantifying maximum possible model performance, as addressed in the current hydrological literature. The AIT perspective teaches us that it is impossible to answer this question objectively without specifying prior beliefs.

Copernicus Gesellschaft Mbh2013

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CIVIL-306: Geotechnical engineering

Les étudiants connaissent les techniques de calculs et de réalisation des fondation d'ouvrages et de soutènement des en terrain meuble.
Ils savent déterminer les facteurs influençant un projet géotechnique et dimensionner les ouvrages afin de satisfaire les états limites externes

CIVIL-308: Rock mechanics

Les étudiants comprennent le comportement mécanique de la roche intacte, des joints et des massifs rocheux et savent déterminer les facteurs influençant un projet. Ils savent utiliser les méthodes appropriées pour analyser et dimensionner l'excavation et le soutènement des ouvrages souterrains.

CIVIL-430: Concrete bridges

Ce cours traite les principaux aspects de la conception et du dimensionnement des ponts en béton armé et précontraint. L'accent est mis sur les ponts poutres. Etude des aspects suivants : optimisation du comportement structural, dimensionnement, dynamique des structures et technologie des matériaux.

Géotechnique

Dans le groupe des géosciences, la géotechnique est la technoscience consacrée à l’étude pratique de la subsurface terrestre sur laquelle notre action directe est possible pour son aménagement et/ou s

Ingénierie des structures

L'ingénierie des structures est un domaine de l'ingénierie et plus particulièrement du génie civil, traitant de la stabilité des constructions (conception et de l'analyse des structures). Une struct

Barrage

Un barrage est un ouvrage d'art hydraulique construit en travers d'un cours d'eau et destiné à en réguler le débit et/ou à stocker de l'eau, notamment pour le contrôle des crues, l'irrigation, l'indu