Axial Capacities of Drilled Displacement Piles Predicted by Spt and CPT Based Methods-PPT Presentation

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The study evaluates methods for predicting the axial load capacity of drilled displacement piles (DDPs) using cone penetration test (CPT) and standard penetration test (SPT) data. It draws on a database of approximately 45 construction projects and more than 100 load-tested piles across sand-like, clay-like, and mixed soils.<br /><br />Researchers compared interpreted failure loads from pile load tests with predictions from 11 load-test interpretation criteria and several CPT- and SPT-based analytical methods. Among the load-test interpretation criteria, Van der Veen’s method most closely matched observed failure loads, followed by the Butler–Hoy and L1–L2 methods.<br /><br />For CPT-based predictions, the Bustamante and Gianeselli method performed best overall across the soil categories. Among the SPT methods, O’Neill and Reese gave the closest agreement for sandy and mixed soils. The results also indicate that ground improvement can significantly affect estimated pile capacity.<br /><br />The study provides a comparative assessment of existing methods for DDP design and highlights which approaches were most reliable for the tested database.

Keywords

drilled displacement piles

axial load capacity

cone penetration test

standard penetration test

pile load tests

Van der Veen method

Bustamante and Gianeselli

O'Neill and Reese

ground improvement

pile design