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作为一种地源热泵技术,地热能源桩以其经济、稳定、有效和环境友好等特点,应用范围越来越广。基于已开展的地热能源桩的现场原位试验和离心模型试验,分析温度变化前后地热能源桩的承载力、桩身附加应力和附加桩侧摩阻力的变化规律,同时进行了室内模型试验。结果表明,设于砂中的模型桩在温度升高时,会造成桩侧摩阻力的降低,这与已有的一些研究结果不同。最后对地热能源桩-土相互作用机理进行了分析。在温度升高时,桩的承载力有较大提高,上半部分桩的桩侧摩阻力降低,而下半部分桩的桩侧摩阻力增加,桩身截面应力会增大;温度降低时,上半部分桩的桩侧摩阻力增大,而下半部分桩的桩侧摩阻力减小,极端情况下桩端附近会出现拉应力,研究结果可为地热能源桩基的设计提供参考。
As a kind of ground source heat pump technology, the geothermal energy pile is more and more widely applied due to its economy, stability, efficiency and environmental friendliness. Based on the in-situ situ test and centrifugal model test of geothermal energy piles, the change law of the bearing capacity of geothermal energy piles before and after temperature change, the additional stress of piles and the side friction resistance of additional piles were analyzed. The indoor model tests were carried out at the same time. The results show that the model piles located in the sand, when the temperature rises, will cause the friction resistance of the pile to decrease, which is different from some existing research results. Finally, the geothermal energy pile-soil interaction mechanism is analyzed. When the temperature rises, the bearing capacity of the pile increases greatly, the friction on the pile side of the pile on the first half decreases, while the friction on the pile side increases in the lower half and the stress on the cross section of the pile increases. When the temperature decreases, The friction on the pile side increases in the upper part of the pile, while the friction on the pile side in the lower part of the pile decreases. In extreme cases, the tensile stress will appear near the pile head. The results can provide reference for the design of the geothermal energy pile foundation.