Numerical solution of torsional bearing characteristics of energy piles considering radial thermal expansion

• Published in: Arabian journal of geosciences Vol. 15; no. 14
• Main Authors: Jiang, Jie, Chen, Chao-qi, Ou, Xiao-duo, Chen, Qiu-yi, Zhang, Peng, Huang, Xi, Liu, Guang-Yang
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 2022; Springer Nature B.V
• Subjects: Bearing capacity; Earth and Environmental Science; Earth science; Earth Sciences; Energy; Friction resistance; Mathematical models; Nonlinear response; Operating temperature; Original Paper; Parametric analysis; Pile foundations; Piles; Plane strain; Plastic zones; Soil; Soil stresses; Soil temperature; Soils; Strain; Temperature distribution; Temperature effects; Temperature fields; Thermal expansion; Thermal stress; Torque; Piles; Energy piles; Radial thermal expansion; Homogeneous soil; Torsion
• ISSN: 1866-7511; 1866-7538
• DOI: 10.1007/s12517-022-10483-x

As a new type of pile foundation, the research on the torsional bearing capacity of energy piles is relatively lacking. Inadequate design of energy piles under torsion may lead to disastrous consequences. This paper calculates the radial thermal stress based on the plane strain model by introducing the plane temperature field equation. Then, the ultimate lateral friction resistance at the pile-soil interface is modified by combining with the stress. The nonlinear stress-strain response of soil has been incorporated into the torque transfer equation by hyperbolic correlation. Finally, a calculation method for the torsional capacity of energy piles considering radial thermal expansion is established. By comparing with the numerical simulation, the rationality of the method in this paper is verified. Several conclusions are drawn from the parametric analysis. First, the radial thermal stress increases sharply at first and then decreases slowly with radial distance, and the maximum value appears in the soil surrounding the pile. Second, increasing the operating temperature can enhance the radial thermal stress, thereby increasing the lateral frictional resistance and delaying the development of the plastic zone. Third, the torsional bearing capacity of the energy pile rises with the temperature when the monotonic temperature load is applied for a long time but has no significant relationship with the working time.