Investigation of laterally loaded helical pile behaviour with laboratory model tests

Helical piles are a steel foundation system that is applied by placing the piles on the soil with a rotational movement in order to safely carry the loads from the structure. When a lateral load is applied directly to the helical piles or when lateral soil movements are affected without any external load; the behavior of helical piles is directly affected by these displacements. In this study, the lateral displacements and load-bearing capacity of the piles were determined by lateral loading in the laboratory model tests on loose soils, using helical piles with specific dimensions. Under laboratory conditions, the load-displacement values were obtained by applying lateral load to the helical piles by using parameters such as the helical number (N), helix diameter (D), load application height (e), pile embedded length (L) and helix spacing (s). As a result of the experimental studies, it has been determined that the lateral load-bearing capacity of the helical piles' increases as the number of helix and diameter of the helix increases. According to the results of the tests performed on double and multiple helixes, the optimum helix spacing / helix diameter (s / D) ratio was determined as approximately 2 and it was determined that the highest lateral load bearing capacity was reached. According to the test results obtained from single helix, it was determined that the lateral load bearing capacity increased as the pile embedded length / shaft diameter (L / d) ratio increased. It is concluded that when the lateral load application height (e) increases, the lateral load carrying capacity decreases.