000203567 001__ 203567
000203567 005__ 20190619023655.0
000203567 0247_ $$2doi$$a10.5075/epfl-thesis-6452
000203567 02470 $$2urn$$aurn:nbn:ch:bel-epfl-thesis6452-3
000203567 02471 $$2nebis$$a10279423
000203567 037__ $$aTHESIS
000203567 041__ $$aeng
000203567 088__ $$a6452
000203567 245__ $$aThermomechanical Characterization of Energy Geostructures with Emphasis on Energy Piles
000203567 269__ $$a2014
000203567 260__ $$bEPFL$$c2014$$aLausanne
000203567 336__ $$aTheses
000203567 502__ $$aProf. I. Botsis (président) ; Prof. L. Laloui (directeur) ; Prof. F. Maréchal,  Prof. J.S. McCartney, Prof. J.-M. Pereira (rapporteurs)
000203567 520__ $$aSuitable developments of sustainable energy sources are drawn by analysing the Energy sector, considering environmental, economic and social aspects. The particular example of Switzerland is detailed with a focus on the energy consumption in the buildings. Based on the statistics from the Swiss Federal Office of Energy, the majority of the energy consumed by the Swiss households and in office and retail spaces is used for space conditioning as well as hot water production. In this scope, energy geostructures represent the next generation of ground heat exchangers for ground source heat pump systems. These are more cost effective than conventional ground heat exchangers, e.g. geothermal boreholes, because they save the specific drilling operations and take advantage of the ground structures required anyway. First, the geotechnical operational design of energy piles is discussed using Thermo-Pile software, a tool developed at the Laboratory of Soil Mechanics of the Swiss Federal Institute of Technology Lausanne (Switzerland) and based on the load-transfer method. Next, the effects of pore water pressure build under temperature variations on the bearing capacities of energy piles are investigated using thermo-hydro-mechanical finite element analyses. This phenomenon, not accounted for in the load-transfer method, could have a significant impact by reducing cyclically the effective contact stress at the pile-soil interface. Then, heat production is investigated on shallow urban tunnels. These geostructures may represent a significant heat source because of their extension. Several solutions were experimentally tested mainly in Austria, considering thermoactive tunnel linings, geotextiles, slabs, walls and prototype self-drilling bolts. The present thesis proposes to deepen the knowledge about heat exchanger anchors as they are the least investigated. Indeed, thermoactive slabs, linings and walls were extensively used on real structures while heat exchanger anchors have only been tested in an embankment in Vienna (Austria). Finally, full-scale experimental investigations of the thermomechanical response of energy piles are carried out. Four 28 m long test piles were built below a water retention tank that is also supported by conventional piles. The test piles are gathered in a tank corner to allow studying group effects. Three thermomechanical response tests are analysed. The first consisted in heating the piles when no structure was built on top of them. Next, each test pile was individually tested once the tank was built. Finally, the entire group was heated in order to observe the relief of pile to pile interactions as a result of a global group expansion. Comparisons of the different thermomechanical response test are achieved in term of pile tip compression, pile top strains and degree of freedom profiles. It is found that the tank construction influences the thermomechanical response of the piles down to the stiff soil layers while their respective position below the raft impacts their responses down to 10 m. The pile to pile interactions are clearly visible on the first level of neighbouring piles (i.e. directly adjacent) and down to the pile tips. Group effects observed during the heating of the entire group doubled the degree of freedom of each test pile, inducing greater pile heaves but reducing differential settlements, therefore reducing internal thermal efforts.
000203567 6531_ $$ageotechnics
000203567 6531_ $$ashallow geothermal energy
000203567 6531_ $$afoundation structure
000203567 6531_ $$aground source heat pump
000203567 6531_ $$apile foundation
000203567 6531_ $$atunnel
000203567 6531_ $$aanchor
000203567 6531_ $$ageostructure
000203567 6531_ $$abearing capacity
000203567 6531_ $$agroup effect
000203567 6531_ $$along term cyclic effect
000203567 6531_ $$athermomechanical response
000203567 6531_ $$adesign tool
000203567 6531_ $$anumerical analysis
000203567 6531_ $$afull-scale experiment
000203567 6531_ $$ascaled model
000203567 700__ $$0245249$$g196138$$aMimouni, Thomas
000203567 720_2 $$aLaloui, Lyesse$$edir.$$g105611$$0240226
000203567 8564_ $$uhttps://infoscience.epfl.ch/record/203567/files/EPFL_TH6452.pdf$$zn/a$$s17820102$$yn/a
000203567 909C0 $$xU10264$$0252080$$pLMS
000203567 909CO $$pthesis-public$$pDOI$$pENAC$$ooai:infoscience.tind.io:203567$$qGLOBAL_SET$$pthesis$$pthesis-bn2018$$qDOI2
000203567 917Z8 $$x108898
000203567 917Z8 $$x108898
000203567 917Z8 $$x108898
000203567 917Z8 $$x108898
000203567 917Z8 $$x108898
000203567 918__ $$dEDME$$cIIC$$aENAC
000203567 919__ $$aLMS_2014
000203567 920__ $$b2014$$a2014-11-28
000203567 970__ $$a6452/THESES
000203567 973__ $$sPUBLISHED$$aEPFL
000203567 980__ $$aTHESIS