Case study on the application of high strain dynamic pile testing to non-uniform bored piles

摘要

Dynamic pile testing is used frequently to prove the performance of driven pre-formed piles in Australia. It is either specified by the designer or is offered as an alternative to conventional static testing by piling contractors. However, it's use on cast in place piles is much less frequent. This paper describes a project at Noosa Heads in Queensland, Australia where an excellent "Grade A" correlation has demonstrated that dynamic testing can provide a good prediction of the load vs displacement behaviour of cast in place piles even when the pile shaft is not as designed. The static test pile had the highest over-consumption of concrete at the site, with more than 2 times the design quantity of concrete used during construction. A non-uniform shaft is known to make dynamic testing more difficult and probably less accurate. Nevertheless a very good correlation was obtained between the static test and the dynamic test results for both overall mobilized resistance and the stiffness response of the pile. The static test included measurements that demonstrate potential problems with static testing and these will also be discussed.