Soil resistance to driving considering effect of pile running on pile installation

The accuracy of the drivability analysis for large-diameter piles is very important for safe pile driving, and the prediction of soil resistance to driving (SRD) is the key in this analysis. The methods often used today do not consider the influence of installation process on SRD. In order to consider the influence of pile running on SRD, high-strain dynamic tests are used to monitor the whole pile-driving procedure where pile running happens in driving. The measured data are analyzed by CAPWAP, and the change of SRD during the pile driving is studied. It can be found that the friction changes obviously before and after pile running. The influence of pile running on SRD is different at different penetration depths. According to the influence of pile running, the totally affected zone, partly affected zone and unaffected zone are divided in the soil. Moreover, the method used to predict SRD is also different in different zones. The proposed method gives a better prediction of SRD than that calculated by the methods often used today.