Efficiency of piles of various cross-sectional forms

Grounds and foundations, underground structures

According to the authors the lack of evaluation methods for efficiency of pile behavior leads to an increased degree of randomness in the selection of type, material, shape and placement of piles, and, as a consequence, to overspending the material, energy, labor costs and, respectively, to more expensive construction. The work is devoted to the determination of the efficiency of piles of various cross-sectional forms (round, square, cross- shaped, T-shaped and double tee forms). A number of methods and criteria for quantitative evaluation of the efficiency of piles were proposed. Furthermore, the results of studies of the pile efficiency depending on the driving depth at the above-mentioned forms of cross-sections were given. Researches have shown that quantitative values of pile efficiency are approximately the same for the following forms for round and square cross-section; for T-shaped and double tee; and the are exactly the same for cross-shaped and T-shaped cross-section. Analysis of considered piles forms showed that maximum efficiency was achieved under the minimum depth of 2 meters, and then it gradually decreased. Also there was found an anomaly: at a depth of 10 meters the efficiency of cross sections with the tabs (III, IV, and V-shaped branchy) again begins to rise slowly. The results allow us to optimize more accurately the selection of the pile component in the foundation design.