Experimental study of the thermodynamic properties of high thermal conductivity energy pile

Abstract

In this paper, high thermal conductivity concrete (containing 4% graphite and 0.6% steel fiber) was prepared as a pile material by a model test. A high thermal conductivity energy pile was produced. The temperature field distribution of the pile and soil, the additional stress of the pile, the soil pressure at the pile end, and the displacement of the pile top were analyzed. The results showed that compared with the thermal conductivity, compressive strength, and flexural strength of ordinary C30 concrete, those of the high thermal conductivity concrete were increased by 30%, 11%, and 9%, respectively. Under load, the additional stress of the pile was large in the middle and small at both ends. After three thermal cycles, the maximum additional tensile and compressive stresses of the pile were 0.48 MPa and −0.58 MPa, respectively. The maximum value of the soil pressure at the pile end decreased with an increase in the number of thermal cycles. Thermal cycles caused cumulative pile top settlement, with a final settlement of 0.26 mm. In practical engineering, the influence of long-term thermal cycles on the safety of buildings should be noted.