As a kind of GSHP（Ground Source Heat Pump）

geothermal energy piles is the economic

stable

efficient

and environmentally friendly way of cooling and heating building. Based on four published field and centrifugal model test studies

the bearing capacity and mobilized stress of pile shaft and lateral friction resistance under the thermal loading are analyzed. At the same time

a model test in sand is done. Its results indicate that the lateral friction decreased with the increasing temperature

which is opposite to the former one. At last

the interaction mechanism between geothermal energy pile and soil is analyzed. When the geothermal energypiles are heated

the bearing capacity will be increased

and the friction resistance of the upper pile will be decreased. In contrast

the friction resistance of the low pile is increased. At the same time

the axial in pile will be enlarged. Whilst the geothermal energy piles are cooled

the friction resistance of the upper pile will be increased

and that of the low pile is decreased. There is even tensile stress in pile under the special case.