Analysis of the construction of foundation piles

Abstract

The paper presents the analysis of structures of foundation piles with or without heat exchangers, their design features, as well as their advantages and disadvantages. We have revealed that most piles have a complicated form of heat exchangers or piles themselves. Heat exchangers can be single, double and triple U-shaped, W-shaped and spiral. Piles with U-shaped heat exchangers are the most promising. Their application excludes the mechanical load on the walls of the building. There are no additional losses for drilling wells. They have increased thermal efficiency and low hydrodynamic heat carrier transfer losses, especially when using heat exchangers with parallel double U-shaped pipes. Such structures reduce impermeability break risk and, accordingly, promote achieving an appropriate level of environmental safety. At the same time, using liquid as a coolant can lead to the destruction of, initially, pipes of heat exchangers, and then piles, due to changes in temperature, pressure and volume. Dissolved oxygen in the liquid coolant promotes deep corrosion of heat exchanger tubes and, as a consequence, the destruction of the reinforced concrete frame piles in general. Using heat exchanger pipes as reinforcement can also lead to their damage and, accordingly, to the above problems. The analysis of available structures of foundation piles can lay down the requirements for perspective design of energy piles and, accordingly, will give an opportunity to develop a new design of a pile with a U-shaped heat exchanger, which takes into account all the disadvantages provided in our paper. First of all, it is necessary to improve the heat exchanger design, namely, the geometry of the cross-section of pipes, the form of the pipe laying in the pile shaft, the methods of fixing the heat exchanger pipes in the pile shaft, as well as the number of such holders.