Energy piles are dual-purpose foundation elements that transfer the building loads to the supporting soil and act as heat exchangers for heating and cooling. Energy piles are subjected to heating and cooling cycles over days and seasons, resulting in cyclic expansion and contraction. The cyclic expansion and contraction bring about the modification of vertical stress and the increase of vertical displacements on the piles, in other words, the thermo-mechanical behavior of the pile, the soil, and the soil–pile interface is changed by the cyclic thermal cycles. Investigation to know the effect of temperature cycles on soil–pile interface characteristics has high academic and significant engineering values. This paper intends to investigate the thermo-mechanical response of soil–pile interface under different types of cyclic thermal loadings, to better understand the behavior of energy piles and their surrounding soils after the buildings are constructed and the geothermal activation. Direct shear tests are performed by using a new interface direct shear test machine composed of a temperature controlling device to assess the influence of different cyclic thermal loadings on the shear behavior of Fontainebleau sand–concrete interface. Direct shear tests are carried out after three different thermal loadings, i.e., a constant temperature of 13 °C, and two different kinds of cyclic cooling–heating​ (8–18 °C) loadings with 10 cycles (namely CT-1 and CT-2). The horizontal stress and horizontal displacement are evaluated after the 10 thermal cycles in CT-1 and CT-2 programs, and the shear results are then compared. The results reveal that the cyclic thermal cycles increase the peak shear strength of CT-2, however they do not significantly affect the residual shear strength of both CT-1 and CT-2. The peak/residual interface friction angle of the reference test is 29.5${}^{\circ }/28$.4°, after the 10 cyclic thermal cycles, it becomes to 28.9${}^{\circ }/27$.9° for CT-1, and 31.7${}^{\circ }/28$.5° for CT-2.

能源桩是双重用途的基础元件，可将建筑荷载转移到支撑土壤，并充当加热和冷却的热交换器。能源堆在数天和季节中经历加热和冷却循环，导致循环膨胀和收缩。循环热胀冷缩引起桩体竖向应力的改变和竖向位移的增加，即循环热力改变桩体、土体及土-桩界面的热力行为。循环。研究温度循环对土-桩界面特性的影响具有较高的学术和工程意义。本文旨在研究不同类型循环热载荷下土-桩界面的热力响应，直剪试验采用由温度控制装置组成的新型界面直剪试验机进行试验，评估不同循环热载荷对枫丹白露砂-混凝土界面剪切行为的影响。直剪试验是在三种不同的热载荷（即 13°C 恒温）和两种不同类型的循环冷却-加热（8-18°C）载荷（10 个循环）（即 CT-1 和 CT）后进行的。 -2）。在CT-1和CT-2程序中，在10次热循环后评估水平应力和水平位移，然后比较剪切结果。结果表明，循环热循环增加了 CT-2 的峰值剪切强度，但并未显着影响 CT-1 和 CT-2 的残余剪切强度。${}^{\circ }/28$.4°，经过10次热循环后，变成28.9${}^{\circ }/27$CT-1 为 0.9°，CT-1 为 31.7${}^{\circ }/28$CT-2 为 0.5°。