Design tools for thermoactive geotechnical systems

This paper presents a review of current design tools used for thermoactive geotechnical systems, along with validation efforts. The capabilities of available analytical methods used for the thermal and thermomechanical design of these systems are evaluated and shortcomings of the existing methods are identified. Although the analytical methods permit accurate prediction of the thermal stress and strain response of thermoactive piles from readily available soil and concrete properties, current shortcomings consist of the ability of the methods to simulate cyclic heating and cooling effects, transient pore water pressure generation and dissipation, and the effects of radial stress changes. Recommendations are provided on how to properly address the current design requirements and the efforts to overcome shortcomings with the development of constitutive relationships fromfurther full scale and laboratory scale experimental studies on thermoactive piles. Furthermore, the need for the development of both simplified analytical tools and advanced finite element models is emphasized. In addition, the existing analytical tools should be validated using field data from recently available case studies of thermoactive piles in varying soil deposits. An urgent need for an extensive design guide for energy geostructures was identified. The guidelines should be targeted towards practitioners and include field observations and measurements, as well as laboratory and numerical studies.