NUMERICAL EVALUATION OF LATERAL BEARING CAPACITY FOR FIXED-HEAD PILES

Piles are used extensively to resist lateral load from earth pressure, inclined load, wind, waves, earthquakes, etc. The behavior of piles subjected to lateral loads is governed by interaction between the pile and the soil, and it is a non-linear, three-dimensional soil-structure interaction problem. Pile properties, including pile stiness and geometry, and soil properties, i.e., unit weight, sti- ness, friction angle, cohesion and the pile/soil interface, play important roles in the response of piles subjected to lateral loads.
Existing methods for the analysis of laterally loaded single piles can be generally classied into the following ve categories: (1) the limit state method; (2) the subgrade reaction method; (3) the p-y method; (4) the elasticity method; and (5) the nite element method. However, the eect of fundamental soil properties (e.g., strength, stiness, and volume change characteristics) on the response of pile and soil cannot be appropriately addressed in these methods. Thus, an investigation into the eects of fundamental pile and soil properties on the soil response of a pile subjected to lateral load is necessary and helpful in improving insight into the soil/structure interaction problem for a laterally loaded pile.
A fundamental study into the soil/ pile interaction response of xed-head piles subjected to static lateral loads in sands is conducted using the non-linear nite element approach. The eects of pile properties, i.e., length and diameter, and soil properties, i.e., the horizontal coe- cient of earth pressure, unit weight and stiness, on the pile response of a pile subjected to lateral load, are also investigated.
In the numerical model, the pile was treated as a linear elastic material and the soil was idealized using the multi-yield-surface plasticity model with a non-associated ow rule. The improvement in pile lateral load was found to be strongly dependent on the pile diameter, soil friction angle, and relative density of the sand. It was also found that the eective embedment length of the pile is more eective than the total length of the pile. Based on the numerical results, eective parameters are discussed and a formula for the lateral bearing capacity of a xed-head pile in sand is recommended.