Foundation piles of the offshore oil platforms in Bohai Bay are usually longer than 100m with a diameter larger than 2m. Thus, thoughtful drivability analysis has to be performed in the design stage because of the high cost and time limitation. It has been shown that to judge if the soil column inside the pile is fully plugged, which will make the pile behave as close-ended, will strongly influence the accuracy of drivability analysis. Engineering practice repeatedly indicates that the currently widely used methods for soil plug judgment often give incorrect results, leading the designers to make a wrong decision. It has been found that this problem is caused by the ignorance of the bearing capacity provided by the soil surrounding the pile. Based on the Terzaghi’s bearing capacity calculation method for deep foundation, a new approach for judging soil plug status is put forward, in which the surcharge effect has been considered and the dynamic effect coefficient is included. This approach has been applied to some practical engineering projects successfully, which may give more reasonable results than the currently used method.