Numerical study on response of a single pile under unidirectional and multidirectional horizontal loadings

In many practical projects, pile foundations are required to resist large horizontal loadings besides vertical loadings. A three-dimensional elastoplastic numerical analysis model was set up, using the FEM software ABAQUS, to study the response of a single pile with a free head or a fixed head under the unidirectional horizontal loading, and to analyze the effect of the multidirectional loading path on the lateral loading capacity of the single pile. In these analyses, the parameters of the soil were determined according to the data of the triaxial tests. It is revealed from the numerical analyses that for the lateral loaded free-head pile, the maximum bending moment occurs at 4D below the soil surface and the maximum vertical displacements of the soil occurs at 0.5D in front of the pile. The lateral loading capacity of the fixed-head pile is about 2.65 times that of the free-head pile, and the maximum bending moment of the former is much larger than that of the latter. The lateral loading capacity under multidirectional paths is apparently smaller than that under unidirectional path. This is consistent with that observed in the experiments. With the increasing aspect ratio, the loading capacity reduces and the maximum force appears earlier.