Negative Skin Friction Behavior of PCC Energy Pile under Heating Cycle

Based on traditional PCC pile, one of new type energy pile was developed. This new PCC energy pile has many advantages, such as, conveniently buried and high thermal conduction efficiency. However, the researches on negative skin friction of this new type energy pile influenced by temperature are relatively little. Based on model test method, the properties of PCC energy pile was carried out. Load-displacement curves under different temperatures and the temperature variation of pile and soil were measured, and the friction of pile shaft was also calculated.The bearing capacity and negative skin friction of PCC energy pile influenced by pile temperatures were discussed and analyzed. The results show that the bearing capacity of PCC energy pile is improved with the increment of pile temperature, which is similar with traditional solid energy pile.At the end of cooling, the direction of mobilized shaft resistance near top part of pile conversed and negative skin friction appeared.