Behavior of Large Bored Single and Group Piles under Lateral Loads in Bangkok Subsoils

Abstract

This study examines the lateral load behavior of large bored piles in Bangkok subsoils, focusing on two-pile groups, three-pile groups, single piles, barrettes loaded along the narrow and wide sides, and T-shaped barrettes. The objective is to assess the lateral load performance of different pile configurations and to calibrate appropriate stiffness parameters for the Hardening Soil model through back-analysis, using three-dimensional finite element simulations. The back-analysis was conducted based on full-scale lateral load test data, with the test piles having diameters of 1.5 m and 1.65 m. The barrettes had cross-sectional dimensions of 0.8 m × 2 m, while the T-shaped barrettes had flange dimensions of 1 m × 3 m and web dimensions of 1 m × 2 m. Results show that two-pile groups, three-pile groups, and T-shaped barrettes achieve the highest lateral load efficiencies, followed by barrettes loaded along the narrow side and single piles. Barrettes loaded along the wide side exhibited the lowest efficiency. The calibrated stiffness, expressed in terms of the total stress for which is suitable for serviceability limit state design, ranged between 200 and 300. Moreover, the findings suggest that a medium-mesh resolution provides a sufficient balance between computational efficiency and accuracy in capturing pre-failure pile behavior.