Abstract:
Recently developed analytical solutions for displacement, strain and stress in energy piles featuring reversible interface behavior, subjected to thermo-mechanical load were normalized into dimensionless form. It is shown that all these solutions depend on several stiffness ratios and geometry of the pile. This includes: 1) ratio of shear stiffness of surrounding soil and elastic modulus of the pile, 2) ratio of normal stiffness of the soil or rock at the pile tip and elastic modulus of the pile, 3) ratio of normal stiffness representing a restraint and the pile head (if present) and elastic modulus of the pile, 4) ratio of length and width (or diameter) of the pile, and 5) diameter of the pile.
In addition to evolution of response along the pile length, for which the corresponding coordinate can be conveniently normalized with respect to length of the pile, maximum displacement, strain and stress can also be obtained in the dimensionless form. Sensitivity study of the energy pile response to thermal and mechanical loads is then conducted, thus showing how different stiffness ratios and geometry of the pile affect the maximum magnitude of displacement, strain and stress. Maximum normalized displacement is governed by these parameters in both cases, thermal and mechanical loads, while maximum normalized strain is independent of these parameters and simply equal to one. However, maximum dimensionless stress is independent of these parameters in case of mechanical loading, but not in the case of thermal loading. In summary, presented dimensionless form of analytical solutions provides a valuable insight into the response of energy piles that is useful for analysis and design.