Statnamic testing of model piles in a clay calibration chamber

The rate of load application during a Statnamic pile test lies between that for static and dynamic pile tests. Current analysis methods offer excellent correlation between Statnamic and static test results for coarse-grained soils. However, over-prediction of pile load capacity can be obtained for fine-grained soils. It is very difficult to explore this anomaly using full scale field tests because of natural soil variability, so a study has been carried out using a model pile installed in similar clay beds prepared in a large triaxial calibration chamber. The instrumented model pile has been loaded at varying rates by a computer controlled servo-hydraulic actuator. The tests have simulated static loading, constant rate of penetration at various rates of penetration, and Statnamic loading. Results suggest that components of the rate effect associated with increased pile penetration rates may be described by a power law relationship.