Pull-out resistance of single piles and parametric study using the Finite Difference Method (FDM)

Many engineering structures both above ground and under the ground surface are subject to forces that create overturning moments upon them. In this study, the structure under consideration is the single pile foundation structure of solar panels. Increasing demand for clean energy is pushing for more economical means of constructing such structures with maximum evaluation focused on the cost of installation and the ultimate strength of the fully loaded structure hence single piles come into place. As studied in the previous paper on the design of the pile element, dimensions of 1.4m pile foundation length and 0.26m diameter are also employed in this paper to determine the pull-out capacity. Strength evaluation is done through numerical simulation using FLAC2D which use the finite difference method to evaluate the input codes in step by step manner while integrating the input parameters in a stress train relation as described in the pull-out code. The dimensions of the model mesh are twice the pile foundation depth, 2L in the y-direction and 2L in the x-direction from the pile vertical axis. Strength evaluation is done on sandy, clay and silty medium to determine the vast array of data for engineering design measures. A parametric study is then done by varying the foundation depth from 0.7m to 2.0m, soil angle of internal friction from 10⁰ to 40⁰ and the inclusivity of gap upon failure. The design dimensions show good bearing capacity with load up to 94kN, 90kN and 80kN for dense sand, silty soil and clay soil respectively. The suggested relations for the pull-out capacity of the single pile regarding the axial ability are within design limits