Finite element modeling of thermo-active diaphragm walls

Abstract

There are two major challenges faced by modern society: energy security, and lowering carbon dioxide gas emissions. Thermo-active diaphragm walls have a large potential to remedy one of these problems, since they are a renewable energy technology that uses underground infrastructure as a heat exchange medium. However, extensive research is required to determine the effects of cyclic heating and cooling on their geotechnical and structural performance. In this paper, a series of detailed finite element analyses are carried out to capture the fully coupled thermo-hydro-mechanical response of the ground and diaphragm wall. It is demonstrated that the thermal operation of the diaphragm wall causes changes in soil temperature, thermal expansion/shrinkage of pore water, and total stress applied on the diaphragm wall. These, in turn, cause displacements of the diaphragm wall and variations of the bending moments. However, these effects on the performance of diaphragm wall are not significant. The thermally induced bending strain is mainly governed by the temperature differential and uneven thermal expansion/shrinkage across the wall.

Keywords

thermo-active diaphragm wall / finite element analysis / thermo-hydro-mechanical coupling / ground source heat pump

References

[1] Brandl H. Energy foundations and other thermo-active ground structures. Geotechnique, 2006, 56(2): 81–122

[2] S Suckling T P, Smith P. Environmentally friendly geothermal piles at Keble College. In: Proceedings of the 9th International Conference on Piling and Deep Foundations. Nice: Deep Foundations Institute, 2002, 1016: 8–15

[3] Laloui L, Di Donna A. Understanding the behaviour of energy geo-structures. Proceedings of the Institution of Civil Engineers-Civil Engineering, 2011, 164(4): 184–191

[4] Amis T, Robinson C, Wong S. Integrating geothermal loops into the diaphragm walls of the Knightsbridge Palace Hotel project. In: EMAP-Basements and Underground Structures, 2010

[5] Bourne-Webb P J, Amatya B, Soga K, Amis T, Davidson C, Payne P. Energy pile test at Lambeth College, London: Geotechnical and thermodynamic aspects of pile response to heat cycles. Geotechnique, 2009, 59(3): 237–248

[6] Bourne-Webb P J .Observed response of energy geostructures. Energy Geostructures: Innovation in underground engineering, 2013: 45–77

[7] Bourne-Webb P J, Bodas Freitas T M, Freitas Assunção R M. Soil-pile thermal interactions in energy foundations. Geotechnique, 2016, 66(2): 167–171

[8] Bourne-Webb P J, Bodas Freitas T M, da Costa Gonçalves R A. Thermal and mechanical aspects of the response of embedded retaining walls used as shallow geothermal heat exchangers. Energy and Building, 2016, 125: 130–141

[9] Amatya B L, Soga K, Bourne-Webb P J, AMIS T. Thermo-mechanical behaviour of energy piles. Géotechnique, 2012, 62(6): 503–519

[10] Knellwolf C, Peron H, Laloui L. Geotechnical analysis of heat exchanger piles. Journal of Geotechnical and Geoenvironmental Engineering, 2011, 137(10): 890–902

[11] Suryatriyastuti M E, Mroueh H, Burlon S. A load transfer approach for studying the cyclic behaviour of thermo-active piles. Computers and Geotechnics, 2014, 55: 378–391

[12] Dupray F, Laloui L, Kazangba A. Numerical analysis of seasonal heat storage in an energy pile foundation. Computers and Geotechnics, 2014, 55: 67–77

[13] Ozudogru T Y, Olgun C G, Senol A. 3D numerical modeling of vertical geothermal heat exchangers. Geothermics, 2014, 51: 312–324

[14] Ma X, Qiu G, Grabe J. Numerical simulation of an energy pile using thermo-hydro-mechanical coupling and a visco-hypoplastic model. Geotechnical Engineering Journal of the SEAGS and AGSSEA, 2014, 45(2): 12–16

[15] Di Donna A, Dupray F, Laloui L. Numerical study of the heating-cooling effects on the geotechnical behaviour of energy piles. In: Coupled Phenomena in Environmental Geotechnics. Torino: CRC Press, 2013: 475–482

[16] Gawecka K A, Taborda D M G, Potts D M, Cui W, Zdravković L, Haji Kasri M S. Numerical modelling of thermo-active piles in London Clay. Proceedings of the Institution of Civil Engineers-Geotechnical Engineering, 2017, 170(3): 201–219

[17] Rotta Loria A F, Laloui L. The interaction factor method for energy pile groups. Computers and Geotechnics, 2016, 80: 121–137

[18] Rotta Loria A F, Vadrot A, Laloui L. Effect of non-linear soil deformation on the interaction among energy piles. Computers and Geotechnics, 2017, 86: 9–20

[19] Rui Y, Yin M. Investigations of pile–soil interaction under thermo-mechanical loading. Canadian Geotechnical Journal, 2018, 55(7): 1016–1028

[20] Rui Y, Soga K. Thermo-hydro-mechanical coupling analysis of a thermal pile. Proceedings of the Institution of Civil Engineers-Geotechnical Engineering, 2019, 172(2): 155–173

[21] Zhuang X, Huang R, Liang C, Rabczuk T. A coupled thermo-hydro-mechanical model of jointed hard rock for compressed air energy storage. Mathematical Problems in Engineering, 2014, 2014: 179169

[22] Sterpi D, Coletto A, Mauri L. Investigation on the behaviour of a thermo-active diaphragm wall by thermo-mechanical analyses. Geomechanics for Energy and the Environment, 2017, 9: 1–20

[23] Rui Y, Yin M. Thermo-hydro-mechanical coupling analysis of a thermo-active diaphragm wall. Canadian Geotechnical Journal, 2018, 55(5): 720–735

[24] Rui Y, Garber D, Yin M. Modelling ground source heat pump system by an integrated simulation programme. Applied Thermal Engineering, 2018, 134: 450–459

Acknowledgement

This research work was part of the Centre for Smart Infrastructure and Construction at University of Cambridge. We thank Professor Kenichi Soga, (UC Berkeley) for advice and help that greatly improved the research results.

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