Thermo-mechanical behaviour of a heat exchanger pile

摘要

The behaviour of a pile subjected to thermo-mechanical solicitations was studied in situ with the aim of quantifying the thermal influence on the bearing capacity of heat exchanger piles. To accomplish this, a pile situated in a building under construction was equipped with a channel system in order to inject heat into it using a special heat pump. Load cells, deformation gauges and thermometers were installed in order to evaluate the behaviour of the pile during seven tests with coupled thermo-mechanical solicitations. The temperature variations applied to the pile were on the order of 15 deg C and the mechanical load reached 1300 kN. The results obtained permitted the quantification of three significant effects brought about by the temperature increase: i. pile uplift, ii. mobilisation of side friction due to the relative displacement of the pile with respect to the ground, iii. additional load generated in the pile by constrained dilation.