能源桩实现了浅层地热能开发与地下工程结构的一体化,拓宽了桩基础的使用功能和应用领域,因此得到了广泛应用,同时,能源桩分析理论也得到发展。荷载传递方法因其计算简单、实用性强等优点而被应用于能源桩的计算和分析中,但热—力耦合荷载传递分析方法仍存在计算结果难以收敛、不能准确反映桩顶实际加载等缺点。分析桩顶误差产生的原因,并基于能源桩荷载传递位移协调算法建立了能源桩的桩顶不平衡力消除迭代法,使得计算结果能准确反映桩顶实际加载条件,从而使得能源桩的热—力耦合承载性能分析更为准确。结合现场测试,验证了桩顶不平衡力消除迭代法的可行性,计算结果表明该方法能够很好地反映荷载—温度联合作用对能源桩承载性能的影响。
Energy piles realize the integration of shallow geothermal energy development and underground engineering structure, and broaden the use function and application field of pile foundation, so they have been widely used, and at the same time promote the development of energy pile analysis theory. The load transfer method has been applied to the calculation and analysis of energy piles due to its advantages of simple calculation and practicality, but the thermo-mechanical load transfer analysis method still has the disadvantages that the calculation results are difficult to converge and do not accurately reflect the actual loading at the top of the pile. The reasons for the pile top error were analyzed, and the iterative method for eliminating the unbalanced force at the pile top of energy piles was established based on the load transfer displacement coordination algorithm of energy piles, so that the calculation results could accurately reflect the actual loading conditions at the pile top, which made the analysis of the thermo-mechanical coupled bearing performance of energy piles more accurate. Combined with the field test, the feasibility of the iterative method for eliminating the unbalanced force at the top of the pile is verified, and the calculation results show that the method can well reflect the effect of the combined load-temperature action on the bearing performance of energy piles.
[1] 路宏伟, 蒋刚, 王昊, 等. 摩擦型能源桩荷载—温度现场联合测试与承载性状分析[J]. 岩土工程学报, 2017, 39(2): 334-342. (Lu Hongwei, Jiang Gang, Wang Hao, et al. In-situ tests and thermo-mechanical bearing characteristics of friction geothermal energy piles[J]. Chinese Journal of Geotechnical Engineering, 2017, 39(2): 334-342. (in Chinese))
[2] Laloui L, Nuth M, Vulliet L. Experimental and numerical investigations of the behaviour of a heat exchanger pile[J]. International Journal for Numerical & Analytical Methods in Geomechanics, 2005, 30(8): 763-781.
[3] Bourne-Webb P, Amatya B, Soga K, et al. Energy pile test at Lambeth College, London: geotechnical and thermodynamic aspects of pile response to heat cycles[J]. Geotechnique, 2009, 59(3): 237-248.
[4] Ng C W W, Shi C, Gunawan A, et al. Centrifuge modelling of heating effects on energy pile performance in saturated sand[J]. Canadian Geotechnical Journal, 2015, 52(8): 1045-1057.
[5] Stewart M A, Mccartney J S. Centrifuge modeling of soil-structure interaction in energy foundations[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2014, 140(4): 04013044.
[6] Goode Ⅲ J C, Mccartney J S. Centrifuge modeling of end-restraint effects in energy foundations[J]. Journal of Geotechnical and Geoenvironmental Engineering, 2015, 141(8): 04015034.
[7] Knellwolf C,Péron H, Laloui L. Geotechnical analysis of heat exchanger piles[J]. Journal of Geotechnical & Geoenvironmental Engineering, 2011, 137(10): 890-902.
[8] Plaseied N. Load-transfer analysis of energy foundations[D]. Boulder: University of Colorado at Boulder, 2012.
[9] 黄胤培, 蒋刚, 路宏伟, 等. 基于指数模型的能源桩热—力耦合荷载传递法[J]. 南京工业大学学报(自然科学版), 2019, 41(1): 96-103. (Huang Yipei, Jiang Gang, Lu Hongwei, et al. Thermo-mechanical coupling load transfer method of energy pile based on exponential model[J]. Journal of Nanjing Tech University(Natural Science Edition), 2019, 41(1): 96-103. (in Chinese))
[10] 宗宸锋, 邵东, 黄胤培, 等. 考虑径向温度效应的能源桩荷载传递分析方法研究[J]. 防灾减灾工程学报, 2019, 39(4): 658-664. (Zong Chenfeng, Shao Dong, Huang Yipei, et al. Research on energy pile load transfer analysis method considering radial temperature effect[J]. Journal of Disaster Prevention and Mitigation Engineering, 2019, 39(4): 658-664. (in Chinese))
[11] 李永辉,吴江斌.基于载荷试验的大直径超长桩承载特性分析[J].地下空间与工程学报,2011,7(5):895-902.(Li Yonghui,Wu Jiangbin.Bearing behavior study of large-diameter and super-long pile based on full-scale field test[J].Chinese Journal of Underground Space and Engineering,2011,7(5):895-902.(in Chinese))
[12] 马语卿,吕亚茹,许宏发,等.XCC桩单桩荷载传递特性的离心机模型试验研究[J].地下空间与工程学报,2019,15(1):84-92.(Ma Yuqing,LüYaru,Xu Hongfa,et al.Centrifugal modeling tests on load transfer mechanism of XCC single pile[J].Chinese Journal of Underground Space and Engineering,2019,15(1):84-92.(in Chinese))
[13] 陈旻.深厚软土地区大直径钻孔桩荷载传递试验研究[J].地下空间与工程学报,2016,12(5):1205-1210,1276.(Chen Min. Study on the load-transfer test for large diameter bored cast-in-situ piles in deep soft clay area[J].Chinese Journal of Underground Space and Engineering,2016,12(5):1205-1210,1276.(in Chinese))
[14] 何慧斌,孙晓立.使用荷载传递法分析抗拔桩的位移[J].地下空间与工程学报,2008,4(2):523-527.(He Huibin,Sun Xiaoli.Analysis on displacement of tension piles by load transfer method[J].Chinese Journal of Underground Space and Engineering,2008,4(2):523-527.(in Chinese))
[15] Ouyang Y, Soga K, Leung Y F. Numerical back-analysis of energy pile test at Lambeth College, London[A]// Geo-frontiers 2011: Advances in Geotechnical Engineering[C]. 2011: 440-449.
[16] Jiang G, Shao D, Lu H W, et al. Full-scale field observations of the thermo-mechanical behavior of different type of energy pile[A]// The 20th International Conference on Soil Mechanics and Geotechnical Engineering[C]. Sydney: Geomechanics for Energy and the Environment, 2021: 100208.
