Experimental Study of Thermal Response of Vertically Loaded Energy Pipe Pile

Energy piles are a relatively new technology that have dual function as heat transferring and load bearing. Due to the influence of temperature cycles, additional thermal stress relative displacement pile will be generated; this is different from mechanism conventional pile. In order study thermodynamic characteristics energy pipe under working conditions field tests were carried out on PHC (prestressed high-strength concrete) without constraining top piles. Displacement gauges arranged pile, concrete strain (temperature, strain) embedded in The variation laws temperature, strain, stress, side friction resistance, during cycling analyzed. test results show exchange system reached stable state after being heated for 5 days summer. average increased by 15.17 °C, 34.68 °C; it was low at both ends high middle part. After winter environment, decreased 10.09 9.54 which middle. generated inside maximum compressive 3.446 MPa tensile 2.69 MPa. neutral point resistance appeared 8 m below top, about 2/3 length. negative summer condition 42.06 KPa, positive 29.93 lateral degraded winter. Under load, final displacements −0.7 mm (0.175%D) 0.77 (0.193%D), respectively.