نشریه ژئومکانیک و ژئوانرژی

نشریه ژئومکانیک و ژئوانرژی

تاثیر سیکل های حرارت بر اندرکنش خاک و گروه شمع انرژی با تحلیل های همبسته ترمو هیدرو مکانیکی

نوع مقاله : مقاله پژوهشی

نویسندگان
مرجان صدرجمالی 1
امیر حمیدی 2
آبتین روز 3
1 گروه عمران، دانشکده فنی و مهندسی، دانشگاه خوارزمی، کرج، البرز
2 گروه مهندسی عمران، دانشکده فنی و مهندسی، دانشگاه خوارزمی، کرج، ایران
3 گروه عمران، دانشکده مهندسی Deakin، ویکتوریا، استرالیا
10.22107/ggj.2026.600163.1273
چکیده
در این پژوهش، پاسخ ترموهیدرومکانیکی گروه‌های شمع انرژیِ مقیدنشده مدفون در خاک رس اشباع بررسی شده است و تمرکز اصلی بر ضریب اندرکنش بین شمع‌های فعال حرارتی و شمع‌های سازه‌ای مجاور قرار دارد. برای این منظور، یک مدل عددی سه‌بعدی توسعه داده شد و با استفاده از مطالعات موردی معتبر مربوط به تحکیم حرارتی، شمع انرژی منفرد و گروه شمع‌ها صحت‌سنجی گردید. سپس، از مدل تأییدشده برای بررسی اثر قطر شمع، طول شمع، فاصله بین شمع‌ها و اندازه گروه شمع تحت دو چرخه حرارتی تکرارشونده استفاده شد. نتایج، عدم تقارن مشخص بین مراحل گرمایش و سرمایش را نشان می‌دهند؛ به‌گونه‌ای که اندرکنش حرارتی در مرحله گرمایش بیشتر از مرحله سرمایش است. این موضوع بیانگر آن است که انبساط شمع در اثر گرمایش عامل اصلی کنترل‌کننده بیشینه اندرکنش نشست بوده است. در مرحله گرمایش، ضریب اندرکنش در حدود 0.03 تا 0.05 به دست آمد، درحالی‌که در مرحله سرمایش این مقدار کمتر و در حدود 0.005 تا 0.02 بود. پارامترهای هندسی نیز به‌صورت توأم بر رفتار اندرکنشی اثرگذار بودند. افزایش فاصله بین شمع‌ها موجب کاهش اندرکنش شمع–شمع شد، درحالی‌که افزایش تعداد شمع‌ها در گروه شدت تأثیرات حرارتی را افزایش داد. همچنین، هنگامی که فاصله و قطر شمع ثابت نگه داشته شدند، افزایش طول شمع موجب کاهش ضریب اندرکنش به میزان حدود 61 تا 68 درصد در مرحله سرمایش و 47 تا 52 درصد در مرحله گرمایش گردید. در اثر گرمایش، تنش‌های محوری فشاری در شمع‌های انرژی ایجاد شد، درحالی‌که سرمایش موجب ایجاد تنش‌های کششی با بزرگی مشابه گردید. این یافته بر ضرورت در نظر گرفتن هر دو مرحله گرمایش و سرمایش در ارزیابی عملکرد و حالت بهره‌برداری (Serviceability) گروه‌های شمع انرژی تأکید می‌کند. در نهایت، یک رابطه ساده‌شده و بی‌بُعد برای برآورد اولیه اندرکنش نشست ناشی از اثرات حرارتی در گروه‌های شمع انرژی مقیدنشده پیشنهاد شده است.
کلیدواژه‌ها
شمع های انرژی
سیکل های حرارت
اندرکنش گروه شمع
ضریب اندرکنش
رس اشباع
مدلسازی ترموهیدرومکانیکی
موضوعات

عنوان مقاله English

Thermal cycling effects on pile–soil–pile interaction in unrestrained energy pile groups: A THM numerical study

نویسندگان English

Marjan Sadrjamali 1
Amir Hamidi 2
Abtin Rooz 3
1 Department of Civil Engineering, School of Engineering, Kharazmi university, Karaj, Alborz
2 Department of Civil Engineering, School of Engineering, Kharazmi University, Tehran, Iran
3 School of Engineering, Deakin University, Waurn Ponds, Victoria, Australia
چکیده English

Energy piles provide a sustainable solution for building heating and cooling while also serving as structural foundation elements. However, cyclic thermal loading can alter pile–soil interaction and affect the settlement response of surrounding structural piles, particularly in groups without pile-head restraint. This study investigates the thermo-hydro-mechanical response of unrestrained energy pile groups embedded in saturated clay, with emphasis on the interaction factor between thermally active piles and nearby structural piles. A three-dimensional numerical model was developed and verified against established thermal consolidation, single energy pile, and pile group case studies. The verified model was then used to examine the effects of pile diameter, length, spacing, and group size under two repeated thermal cycles. The results reveal a clear heating–cooling asymmetry, with greater thermal interaction during heating, indicating that pile expansion governed the maximum settlement interaction. During heating, the interaction factor was approximately 0.03–0.05, while during cooling it was lower, approximately 0.005–0.02. The geometrical variables acted in combination: increased spacing reduced pile-to-pile interaction, larger pile groups intensified the thermal influence, and longer piles reduced the interaction factor by about 61–68% during cooling and 47–52% during heating when pile spacing and diameter were kept constant. Heating generated compressive axial stresses in the energy piles, while cooling produced tensile stresses of comparable magnitude, highlighting the need to consider both phases in serviceability assessment. A simplified dimensionless expression is proposed for preliminary estimation of thermally induced settlement interaction in unrestrained energy pile groups.

کلیدواژه‌ها English

Energy piles
Thermal cycling
Pile group interaction
Interaction factor
Saturated clay
Thermo-hydro-mechanical modelling
[1]  Zhou, J., Zhang, Rh., Yu, Jl., Jin Sh (2026) Field study on heat transfer performance and thermo-mechanical properties of pre-bored PHC energy pile. Sci Rep 16: 7781. https://doi.org/10.1038/s41598-026-37817-z.
[2]  Dehghan Haddad E, Janalizadeh Choobbasti A, Ghasemi Fare O (2024) Laboratory and numerical study of energy pile behavior under different thermal loading. Innov Infrastruct Solut 9: 190. https://doi.org/10.1007/s41062-024-01503-8.
[3]  Azhar M, Yadav S, Mondal S, Sharma V (2024) Numerical investigation on the thermo-mechanical response of geothermal energy pile in East Indian climatic condition. Int J Civ Eng 22: 2147–2165. https://doi.org/10.1007/s40999-024-01012-w.
[4]  Amirdehi HA, Shooshpasha I (2023) Contributions of constraints to mechanical fields of energy pile foundation. Innov Infrastruct Solut 8: 153. https://doi.org/10.1007/s41062-023-01115-8.
[5]  Saggu R, Chakraborty T (2016) Thermomechanical response of geothermal energy pile groups in sand. Int J Geomech 16(4): 04015100. https://doi.org/10.1061/(ASCE)GM.1943-5622.0000567.
[6]  Ghasemzadeh H, Aliverdi A. (2026) Energy piles: behavior and geoenvironmental challenges. Geomechanics and Geoenergy Journal, 8(4), pp. 75-97. https://doi.org/10.22107/ggj.2026.596200.127.
[7]  Fang J, Feng S, Zhao Y, Zhang Z, Chen H (2025) Effects of thermohydromechanical response at the soil–pile interface on the bearing performance of energy piles. J Geotech Geoenviron Eng 151(1): 04024143. https://doi.org/10.1061/JGGEFK.GTENG-12464.
[8]  Rafai M, Salciarini D, Vardon PJ (2025) Energy pile displacements due to cyclic thermal loading at different mechanical load levels. Acta Geotech 20(6): 3067–3086. https://doi.org/10.1007/s11440-025-02556-4.
[9]  Rotta Loria A, Laloui L (2016) The interaction factor method for energy pile groups. Comput Geotech 80: 121–137. https://doi.org/10.1016/j.compgeo.2016.07.002.
[10]  Rotta Loria AF, Laloui L (2017) Thermally induced group effects among energy piles. Géotechnique 67(5): 374–393. https://doi.org/10.1680/jgeot.16.P.039.
[11]  Cesaro R, Di Laora R, Iodice C, Mandolini A (2024) Interaction domains for capacity- and performance-based design of pile groups. Acta Geotech 19: 4695–4714. https://doi.org/10.1007/s11440-023-02168-w.
[12]  Di Donna A, Rotta Loria AF, Laloui L (2016) Numerical study of the response of a group of energy piles under different combinations of thermo-mechanical loads. Comput Geotech 72: 126–142. https://doi.org/10.1016/j.compgeo.2015.10.023.
[13]  Qiu C, Vasilescu R, Doghman M, Mroueh H, Bourne-Webb PJ (2025) Long-term thermo-mechanical behaviour of an energy pile installed in clay: field experiments and numerical simulations. Energy Build 349: 116498. https://doi.org/10.1016/j.enbuild.2025.116498.
[14]  Liu M, Wang R, Zhou Y (2025) Numerical study on the thermo-hydro-mechanical behavior of energy micropiles in hypoplastic soft clay under cyclic thermal loading. Int J Numer Anal Methods Geomech 49(12): 2731–2748. https://doi.org/10.1002/nag.4007.
[15]  Ghorbani A, Zhang C, Li X (2026) Numerical study of energy piles in unsaturated soils. Comput Geotech 178: 106845. https://doi.org/10.1016/j.compgeo.2025.106845.
[16]  Di Donna A, Laloui L (2015) Numerical analysis of the geotechnical behaviour of energy piles. Int J Numer Anal Methods Geomech 39(8): 861–888. https://doi.org/10.1002/nag.2341.
[17]  Ding X, Zhang D, Wang C, Bouazza A, Kong G (2023) Thermally induced mechanical interactions of energy pile groups subjected to cyclic nonsymmetrical thermal loading. Comput Geotech 162: 105705. https://doi.org/10.1016/j.compgeo.2023.105705.
[18]  Wang ZJ, Fang PF, Zhang RH, Wang KH, Xie XY (2019) FEM analysis and simplified approach for a single energy pile subjected to thermo-mechanical loads. Math Probl Eng 2019: 2098350. https://doi.org/10.1155/2019/2098350.
[19]  Murphy KD, McCartney JS, Henry KS (2015) Evaluation of thermo-mechanical and thermal behavior of full-scale energy foundations. Acta Geotech 10(2): 179–195. https://doi.org/10.1007/s11440-013-0298-4.
[20]  Loveridge FA, Powrie W (2013) Pile heat exchangers: thermal behaviour and interactions. Proc Inst Civ Eng Geotech Eng 166(2): 178–196. https://doi.org/10.1680/geng.10.00098.
[21]  Al-Defae A, Al-Rubaye A, Hytiris N, Jefferson I, Chapman DN, Faramarzi A (2024) Full-scale in-situ tests on a displacement cast in situ energy pile: effects of cyclic thermal loads under different mechanical load levels on pile stress and strain. Geomech Energy Environ 40: 100606. https://doi.org/10.1016/j.gete.2024.100606.
[22] Coccia CJR, McCartney JS (2016) Thermally induced pore water pressures, strains, and preconsolidation pressure of compacted clay. J Geotech Geoenviron Eng 142(10): 04016057. https://doi.org/10.1061/(ASCE)GT.1943-5606.0001522.
[23]  Cekerevac C, Laloui L (2004) Experimental study of thermal effects on the mechanical behaviour of a clay. Int J Numer Anal Methods Geomech 28(3): 209–228. https://doi.org/10.1002/nag.332.
[24]  Sani AK, Singh RM, Amis T, Cavarretta I (2013) A review on the performance of geothermal energy pile foundation, its design process and applications. Renew Sustain Energy Rev 24: 450–460. https://doi.org/10.1016/j.rser.2013.03.040.
[25]  Mirfallah Lialestani SP, Parcerisa D, Himi M, Shahri AA (2024) A novel modified bat algorithm to improve the spatial geothermal mapping using discrete geodata in Catalonia-Spain. Model Earth Syst Environ 10: 4415–4428. https://doi.org/10.1007/s40808-024-01992-7.
[26]  Shahri AA, Shan C, Larsson S (2022) A novel approach to uncertainty quantification in groundwater table modeling by automated predictive deep learning. Nat Resour Res 31(3): 1907–1924. https://doi.org/10.1007/s11053-022-10051-w.
[27]  Mirfallah Lialestani SP, Parcerisa D, Himi M, Shahri AA (2022) Generating 3D geothermal maps in Catalonia, Spain using a hybrid adaptive multitask deep learning procedure. Energies 15: 4602. https://doi.org/10.3390/en15134602.
[28]  Poulos HG, Davis EH (1980) Pile foundation analysis and design. Wiley, New York.
[29]  Abdel-Azim OA, Abdel-Rahman K, El-Mossallamy YM (2020) Numerical investigation of optimized piled raft foundation for high-rise building in Germany. Innov Infrastruct Solut 5: 11. https://doi.org/10.1007/s41062-019-0258-4.
[30]  Shaaban MGI, Kenawi MA, Senoon AA, Abd El-Naiem MA (2023) Effects of excavation and construction sequence on behavior of existing pile groups. Innov Infrastruct Solut 8: 223. https://doi.org/10.1007/s41062-023-01193-8.
[31]  Mylonakis G, Gazetas G (1998) Settlement and additional internal forces of grouped piles in layered soil. Géotechnique 48(1): 55–72. https://doi.org/10.1680/geot.1998.48.1.55.
[32]  Sailer C, Koppel A, Adam D (2012) Thermally induced interaction effects in energy pile groups. Acta Geotech 7(2): 109–124. https://doi.org/10.1007/s11440-012-0152-3.
[33]  Park S, Lee SR, Nguyen T (2013) Thermo-mechanical interaction behavior of energy pile groups using interaction factors. Comput Geotech 49: 1–12. https://doi.org/10.1016/j.compgeo.2012.09.006
[34]  Wang C, Zhang D, Li X, Liu H (2024) Thermomechanical analysis of energy piles using a load-transfer approach considering soil coupling effects. Comput Geotech 168: 106147. https://doi.org/10.1016/j.compgeo.2024.106147.
[35]  Liu C, Li J, Zhou P, Liu G, Li P (2025) Thermo-hydro-mechanical behavior of energy piles in partially saturated soils: a theoretical prediction approach. Comput Geotech 185: 107332. https://doi.org/10.1016/j.compgeo.2025.107332.
[36] Huang L, Ding Z, Song C (2025) A novel three-dimensional analytical model for the thermomechanical responses of energy piles and the surrounding soil based on thermoelastic theory. Int J Numer Anal Methods Geomech 49(12): 2749–2762. https://doi.org/10.1002/nag.4010.
[37]  Rafai M, Tafili M, Dong Y, Vardon PJ (2026) Thermo-plastic response of energy piles during long-term monotonic cooling. Comput Geotech 191: 107839. https://doi.org/10.1016/j.compgeo.2025.107839.
[38]  Al-Khoury R, Bonnier PG (2006) Efficient finite element formulation for geothermal heating systems. Part II: transient analysis. Int J Numer Methods Eng 67(5): 725–745. https://doi.org/10.1002/nme.1650.
[39]  Cui C, Liu Z, Liu J, You Y (2025) Thermo-mechanical coupling model for energy piles: dynamic interface behavior and sustainable design implications. Buildings 15(21): 3984. https://doi.org/10.3390/buildings15213984.
[40]  Dassault Systèmes SIMULIA (2013) Abaqus 6.13 documentation (User's Guide and Analysis User's Guide). SIMULIA, RI.
[41]  Sadrjamali M, Hamidi A (2025) The use of interaction factor for analysis of energy pile groups without head restraints. Geomech Geoeng 20(4): 687–706. https://doi.org/10.1080/17486025.2024.2439431.
[42]  Lewis RW, Schrefler BA (1998) The finite element method in the static and dynamic deformation and consolidation of porous media. John Wiley & Sons, Chichester.
[43]  Lotfi E, Delfan S, Hamidi A, Shahir H, Asadollahfardi G (2014) A numerical approach for one-dimensional thermal consolidation of clays. Int J Civ Eng 12(1): 85–91.
[44]  Bourne-Webb PJ, Amatya B, Soga K, Amis T, et al. (2009) Energy pile test at Lambeth College, London: geotechnical and thermodynamic aspects of pile response to heat cycles. Géotechnique 59(3): 237–248. https://doi.org/10.1680/geot.2009.59.3.237.
[45]  Salciarini D, Ronchi F, Tamagnini C (2017) Thermo-hydro-mechanical response of a large piled raft equipped with energy piles: a parametric study. Acta Geotech 12: 703–728. https://doi.org/10.1007/s11440-016-0463-6
نشریه ژئومکانیک و ژئوانرژی
دوره 9، شماره 1
بهار 1405
صفحه 1-23