(1. College of Civil Engineering and Architecture，Guangxi University，Nanning，Guangxi 530004，China；2. Key Laboratory of Disaster Prevention and Structural Safety of Ministry of Education，Guangxi University，Nanning，Guangxi 530004，China；
3. Guangxi Key Laboratory of Disaster Prevention and Engineering Safety，Guangxi University，Nanning，Guangxi 530004，China)
Abstract：To investigate the effect of pile-side soil softening on the thermal response of energy piles，based on the load transfer method and the energy balance principle，a nonlinear analysis method for the thermal response of energy piles considering the softening of pile-side soil is proposed. In the method，the relationship between pile-side soil shear stress and displacement is described by a skin friction softening model，the relationship between pile-tip reaction and displacement is captured by a hyperbolic model，and the Masing criterion is introduced to construct the loading and unloading function of soil，which is compared with the existing experimental and numerical methods to verify the correctness of the method in this paper. Finally，the influence of relevant softening parameters on the thermal response of the energy piles is analyzed，and the influence of the pile head stiffness coefficient on the null point is explored. The results show that：(1) both the failure ratio of skin friction and the ultimate shear displacement ratio have an impact on the thermal stress，where the effect of both on the thermal stress presents different change rules under the same thermal load，and the thermal stress caused by both increases with the increase of the thermal load. (2) When the superstructure load is small(≤10% Pu)，the value of the thermal stress is larger，and the influence of parameter on the thermal stress is more significant compared with parameter ，but the difference decreases with the increase of the superstructure load. (3) With the increase of the pile head stiffness coefficient ，the null point gradually approaches the pile head，and its position corresponding to the heating condition is always slightly lower than that of the cooling condition.
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2023, Vol. 42 
