Predicting the Ultimate Axial Resistance of Single Driven Piles

摘要

Caltrans' pile load-test data was collected, evaluated. And put into a database. Additional field work was performed at approximately 50 load-test locations to improve the site characterization information. Existing pile capacity estimation procedures were evaluated using the load-test database. Current methods predicted capacity reasonably well at clay dominated sites, but did relatively poorly at sand dominated sites. A simple SPT based predictive method was developed for sand sites. Sixteen existing methods of predicting the ultimate side resistance of single driven piles were evaluated against the uplift test pile database compiled from Caltrans' archives. These methods included methods based on standard penetration tests (SPT), laboratory tests, electric cone penetration tests (CPT), and piezocone penetration tests (CPTU). From this evaluation, the overall variability in the predictions made by these methods was found to be due primarily to variability in the predictions of the methods in sand. For this particular dataset, of the methods for piles in sand, the method with the lowest variability was Decourt's (1982) SPT-based method. Decourt's method, which is applicable to piles in both sand and clay, was also found to perform reasonably well in clay.