The influence of loading rate on pile behaviour in clay

The Statnamic test is a recently developed method of assessing the load carrying characteristics of a foundation pile. The rate of load application during the test lies between that for the static and dynamic tests. Current analysis methods offer excellent correlation between static and Statnamic tests for coarsegrained soils. However, over-predictions of capacity may be obtained for fine-grained soils. Present analyses of the Statnamic test are based upon field studies that are influenced by soil variation. Thus a clay calibration chamber is being used to produce repeatable instrumented beds of clay. An instrumented model pile placed in the bed can be loaded at varying rates by a computer controlled servo-hydraulic actuator. Results from the modeling will be used to improve analysis methods and will also govern the design of a full-scale study. Initial results suggest the rate effect associated with increased pile deformation rates adequately fits a power law relationship.