考虑桩端持力层效应的能源桩受力变形特性研究

方金城; 冯世进; 赵勇

doi:10.11779/CJGE20230710

考虑桩端持力层效应的能源桩受力变形特性研究 English Version

方金城¹,
冯世进^{1, 2, ,},
赵勇¹

1.
同济大学土木工程学院地下建筑与工程系, 上海 200092
2.
同济大学岩土及地下工程教育部重点实验室, 上海 200092

基金项目:

上海市科技创新行动计划项目 22dz1207000

上海市教育委员会科研创新计划项目 2023ZKZD25

上海市科技创新行动计划扬帆计划项目 23YF1449000

土木工程I类高峰学科建设经费资助项目

详细信息

作者简介:
冯世进(1978—)，男，博士，教授，主要从事环境岩土与能源岩土等方面的教学和研究工作。E-mail: fsjgly@tongji.edu.cn

通讯作者:
冯世进, E-mail: fsjgly@tongji.edu.cn

中图分类号: TU432
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- 文章访问数: 501
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出版历程
- 收稿日期: 2023-07-24
- 网络出版日期: 2024-04-17
- 刊出日期: 2024-09-30

Investigations on thermomechanical behavior of energy piles considering bearing stratum effects at pile end

1.
Department of Geotechnical Engineering, College of Civil Engineering, Tongji University, Shanghai 200092, China
2.
Key Laboratory of Geotechnical and Underground Engineering of the Ministry of Education, Tongji University, Shanghai 200092, China

摘要

摘要: 能源桩作为一种具备建筑承载和地热开发双重功能的新型建筑节能技术，近年来得到了越来越广泛的研究和关注。温度荷载的施加对桩体的设计和安全服役带来了新的挑战，但现有理论计算方法仍未能全面揭示热力耦合作用下不同承载性状能源桩的受力变形特性。基于弹性分析理论框架，进一步考虑了桩端持力层的影响，建立了能源桩热力分析模型，并结合典型现场试验结果进行了模型验证，着重分析了地层结构特征和桩基几何参数对能源桩荷载传递及位移行为的影响。研究结果表明：热致轴向荷载将随着持力层刚度的增加而增加，相较于摩擦型桩，温度变化将导致支承于硬持力层的能源桩产生更大的温度应力；桩端持力层、桩周土体及桩顶刚度情况是影响热致应力大小和分布以及热致位移的关键因素。基于理论模型获得的归一化计算结果旨在实现对能源桩热致应力及位移的估算，为不同承载性状能源的设计计算提供参考依据。
- 能源桩 /
- 能源地下结构工程 /
- 承载性状 /
- 弹性分析 /
- 热力耦合
Abstract: As a new type of energy-saving technology, the energy piles have received increasing attention due to their dual functions of load bearing and heat transferring. The application of thermal loads poses new challenges for the design and serviceability performance of the energy piles. However, in the existing theoretical studies, the stress-deformation characteristics of the energy piles subjected to the combined thermomechanical loading under different bearing conditions have not been fully revealed. In this study, an analytical model for the energy piles under different bearing conditions is established based on the framework of the elastic analysis theory, taking into account the effects of the end-bearing layer. The model is validated against the field test data. This study focuses on analyzing the effects of geotechnical conditions and geometrical parameters of the piles on the load transfer and displacement behavior of the energy piles. The results show that the thermally induced axial loads increase with the stiffness of the bearing layer. Compared to the floating-bearing piles, temperature variations will cause greater thermal stress in the piles bearing on stiff soil strata. The stiffnesses of the end-bearing layer, surrounding soil and pile head are the critical factors affecting the magnitude and distribution of the thermally induced stress and displacement. The normalized calculated results obtained from the analytical model can be used to estimate the thermally induced stress and displacement of the energy piles in practice and provide a reference for the design and calculation of the energy piles under different bearing conditions.
- energy piles /
- energy geostructure /
- bearing behavior /
- elastic analysis /
- thermomechanical coupling

HTML全文

图 1 考虑桩端持力层效应的能源桩热力耦合分析模型

Figure 1. Analytical model for thermomechanical behavior of energy piles considering bearing stratum effects at pile end

下载: 全尺寸图片幻灯片

图 2 洛桑现场温度荷载作用下能源桩桩顶位移

Figure 2. Head displacements of energy piles under thermal loading in Lausanne case

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图 3 洛桑现场热力耦合荷载作用下能源桩轴向荷载分布

Figure 3. Distribution of axial load of energy piles under combined.thermomechanical loading in Lausanne case

下载: 全尺寸图片幻灯片

图 4 不同持力层条件下能源桩热力响应特性

Figure 4. Thermomechanical behavior of energy piles under different bearing layer conditions

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图 5 不同桩端持力层条件下能源桩的热应力分布

Figure 5. Distribution of thermal stress of energy piles under different bearing layer conditions

下载: 全尺寸图片幻灯片

图 6 桩周土体刚度对能源桩热应力分布影响

Figure 6. Effects of the stiffness of the surrounding soil on the.thermal stress of energy piles

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图 7 桩顶约束对能源桩热应力分布影响

Figure 7. Effects of head restraint on thermal stress of energy piles

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图 8 长径比对能源桩热应力分布影响

Figure 8. Effects of slenderness ratios on thermal stress of energy piles

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图 9 不同持力层条件下能源桩热致位移

Figure 9. Thermally induced head displacements of energy piles under different bearing layer conditions

下载: 全尺寸图片幻灯片

图 10 桩周土体刚度对能源桩热致位移影响

Figure 10. Effects of stiffness of surrounding soil on head displacement of energy piles

下载: 全尺寸图片幻灯片

参考文献(23)

[1]	刘汉龙, 孔纲强, 吴宏伟. 能量桩工程应用研究进展及PCC能量桩技术开发[J]. 岩土工程学报, 2014, 36(1): 176-181. LIU Hanlong, KONG Gangqiang, WU Hongwei. Applications of energy piles and technical development of PCC energy piles[J]. Chinese Journal of Geotechnical Engineering, 2014, 36(1): 176-181. (in Chinese)
[2]	B BRANDL H. Deep Foundations on Bored and Auger Piles: Energy Piles and Diaphragm Walls for Heat Transfer from and into the Ground[M]. London: CRC Press, 1998.
[3]	AMATYA B L, SOGA K, BOURNE-WEBB P J, et al. Thermo-mechanical behaviour of energy piles[J]. Géotechnique, 2012, 62(6): 503-519. doi: 10.1680/geot.10.P.116
[4]	方金城, 孔纲强, 孟永东, 等. 低承台2×2能量桩基础单桩运行热力耦合特性研究[J]. 岩土工程学报, 2020, 42(2): 317-324. FANG Jincheng, KONG Gangqiang, MENG Yongdong, et al. Thermo-mechanical coupling characteristics of single energy pile operation in 2×2 pile-cap foundation[J]. Chinese Journal of Geotechnical Engineering, 2020, 42(2): 317-324. (in Chinese)
[5]	FANG J, KONG G, YANG Q. Group performance of energy piles under cyclic and variable thermal loading[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2022, 148(8): 04022060. doi: 10.1061/(ASCE)GT.1943-5606.0002840
[6]	GASHTI E H N, MALASKA M, KUJALA K. Analysis of thermo-active pile structures and their performance under groundwater flow conditions[J]. Energy and Buildings, 2015, 105: 1-8. doi: 10.1016/j.enbuild.2015.07.026
[7]	KONG G, FANG J, LV Z, et al. Effects of pile and soil properties on thermally induced mechanical responses of energy piles[J]. Computers and Geotechnics, 2023, 154: 105176. doi: 10.1016/j.compgeo.2022.105176
[8]	MORADSHAHI A, FAIZAL M, BOUAZZA A, et al. Effect of nearby piles and soil properties on thermal behaviour of a field-scale energy pile [J]. Canadian Geotechnical Journal, 2021, 58(9): 1351-1364. doi: 10.1139/cgj-2020-0353
[9]	KNELLWOLF C, PERON H, LALOUI L. Geotechnical analysis of heat exchanger piles[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2011, 137(10): 890-902. doi: 10.1061/(ASCE)GT.1943-5606.0000513
[10]	PASTEN C, SANTAMARINA J C. Thermally induced long- term displacement of thermoactive piles[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2014, 140(5): 06014003. doi: 10.1061/(ASCE)GT.1943-5606.0001092
[11]	CHEN D, MCCARTNEY J S. Parameters for load transfer analysis of energy piles in uniform nonplastic soils[J]. International Journal of Geomechanics, 2017, 17(7): 04016159. doi: 10.1061/(ASCE)GM.1943-5622.0000873
[12]	费康, 戴迪, 洪伟. 能量桩单桩工作特性简化分析方法[J]. 岩土力学, 2019, 40(1): 70-80, 90. FEI Kang, DAI Di, HONG Wei. A simplified method for working performance analysis of single energy piles[J]. Rock and Soil Mechanics, 2019, 40(1): 70-80, 90. (in Chinese)
[13]	徐新丽, 蒋刚, 路宏伟, 等. 能源桩热-力半耦合弹性理论分析方法[J]. 南京工业大学学报(自然科学版), 2019, 41(1): 121-128. doi: 10.3969/j.issn.1671-7627.2019.01.018 XU Xinli, JIANG Gang, LU Hongwei, et al. Elasticity theory of energy pile under thermal-mechanical semi-coupling[J]. Journal of Nanjing Tech University (Natural Science Edition), 2019, 41(1): 121-128. (in Chinese) doi: 10.3969/j.issn.1671-7627.2019.01.018
[14]	ROTTA LORIA A F, VADROT A, LALOUI L. Analysis of the vertical displacement of energy pile groups[J]. Geomechanics for Energy and the Environment, 2018, 16: 1-14. doi: 10.1016/j.gete.2018.04.001
[15]	MATTES N S. The influence of radial displacement compatibility on pile settlement[J]. Géotechnique, 1969, 19(2): 157-159.
[16]	BATINI N, ROTTA LORIA A F, CONTI P, et al. Energy and geotechnical behaviour of energy piles for different design solutions[J]. Applied Thermal Engineering, 2015, 86: 199-213. doi: 10.1016/j.applthermaleng.2015.04.050
[17]	POULOS H G, MATTES N S. The behaviour of axially loaded end-bearing piles[J]. Géotechnique, 1969, 19(2): 285-300. doi: 10.1680/geot.1969.19.2.285
[18]	MATTES N S, POULOS H. G. The analysis of downdrag in end-bearing piles[C]// 7th International Conference on Soil Mechanics and Foundation Engineering, Mexico, 1969: 204-209.
[19]	MINDLIN R D. Force at a point in the interior of a semi-infinite solid[J]. Journal of Applied Physics, 1936, 7(5): 195-202.
[20]	POULOS H G, DAVIS E H. Pile Foundation Analysis and Design: Settlement Analysis of Single Piles[M]. New York: Wiley, 1980.
[21]	D'APPOLONIA E, ROMUALDI J P. Load transfer in end-bearing steel H-piles[J]. Journal of the Soil Mechanics and Foundations Division, 1963, 89(2): 1-25. doi: 10.1061/JSFEAQ.0000496
[22]	LALOUI L, NUTH M, VULLIET L. Experimental and numerical investigations of the behaviour of a heat exchanger pile[J]. International Journal for Numerical and Analytical Methods in Geomechanics, 2006, 30(8): 763-781. doi: 10.1002/nag.499
[23]	桩基地热能利用技术标准: JGJ/T 438—2018[S]. 北京: 中国建筑工业出版社, 2018. Technical Standard for Utilization of Geothermal Energy Through Piles: JGJ/T 438—2018[S]. Beijing: China Architecture & Building Press, 2018. (in Chinese)