A new type of pile used in frozen soil foundation

It is well known that there are three problems to be solved for pile foundations in the cold regions on the Qinghai–Tibet plateau. They are the tension force on the pile induced by the frost heaving surrounding soil, the negative frictional effect induced by foundation thawing, and the long refreezing period of the surrounding soil after the pile is cast with the thawed soil refrozen even for a long time. In this paper, a new pile is proposed to solve these problems. The new pile, made of concrete, is carved with grooves refilled with large-grained porous materials. With this new pile, soil around it can be cooled and the permafrost table can be raised by the convection of porous media under the natural temperature fluctuation. Also, the stress fields and the bearing capacity of this grooved pile are analyzed in order to study its reinforcing mechanism, on the basis of which, this paper suggests the principle and method for the design and construction of the new pile in the cold region on the Qinghai–Tibet Plateau.