The incorporation of heat exchangers into geostructures leads to changes in the temperature of the adjacent soil. Important issues arise about the effect of temperature variations on hydro-mechanical soil behaviour. The objective of this paper is to improve the understanding and the quantification of the impact of temperature variation on the bearing capacity of thermo-active piles. Currently, the design of the deep foundations is based on the results of in situ penetrometer or pressuremeter tests while there is no published data on the effect of temperature on in situ tests results allowing to specifically assess thermo-active piles behaviour. Herein, an experimental device is developed to carry out mini-pressuremeter tests under controlled laboratory conditions. Mini-pressuremeter tests are performed on an illitic soil in a thermo-regulated metric scale container subjected to a range of temperature from 1 to 40 °C. The results showed a slight decrease in the pressuremeter modulus (Ep) and a significant decrease in the creep pressure (pf) and the limit pressure (pl) as the temperature 2 increased. The results showed also the reversibility of this effect during a heating-cooling cycle through the investigated temperature range, while the effect of a cooling-heating cycle was only partially reversible. In the case of several thermal cycles, the effect of the first cycle proved to be decisive on the soil parameters.