Simulated Pile Load-Movement Incorporating Anticipated Soil Set-Up

Abstract

Dynamic pile testing and related data analysis methods are routinely used to measure soil resistance effects, estimate static pile load bearing capacity, and predict pile load-movement relationship. Analysis results represent conditions at the time of testing. For piles driven into soils with beneficial time-dependent characteristics, the capacity increases with time following the initial driving due to favorable geotechnical effects. In practice, construction scheduling constraints often restrict the evaluation of long-term pile capacity and limit the verification testing to a short period following initial driving. This paper presents a method for predicting future pile load-movement relationship based on end of driving and short-term restrike dynamic testing results. A case study is presented where field dynamic tests were performed with a Pile Driving Analyzer (PDA) and CAPWAP computer analysis during initial driving and restrike eleven days later. The CAPWAP method was also used to predict the pile load-movement graph expected at seventeen days after end of initial driving for comparison with results from a full-scale conventional static loading test to be independently performed at that time. Good correlation was obtained between the dynamically predicted and full-scale static load test results based on the proposed method.