Evaluation of lateral capacity for flexible drilled shafts in cohesionless soils

This study aimed to evaluate and improve the p–y curve method for use in the lateral analysis of flexible circular drilled shafts in cohesionless soils. Onsite circular drilled shaft lateral load test data from all over the world were collected, and the applicability of O’Neill and Murchison's p–y curve method was evaluated by comparing the measured values with the method's predicted values. Results showed that the current predictions were underestimated after applying the method to a database of flexible circular drilled shafts in cohesionless soils. Then, the difference (ΔQ) between the predicted value (Q(p)) and measured value (Q(m)) was normalized using the measured value (ΔQ/Q(m)) to determine the percent difference, and an average value of − 47% was produced. The difference ratio between the measured and predicted values was proportional to the diameter of the pile. To calibrate the prediction of the current method, this study applied two parameters (α and β) as modifications to reduce ΔQ. The parameters were decided by using the average difference ratio and average absolute difference methods. The reliability and consistency of the prediction of the p–y curve method were enhanced by applying the recommended modifying parameters. Specific design recommendations were also provided based on the proposed modifications on the original p–y curve.