Field study of parallel seismic testing for evaluating the bottom depth of existing piles

In this paper, a method for evaluating the bottom depth of existing piles is proposed based on a field study of practical engineering. The applicability of existing methods for determining the depth of the pile bottom in PS testing is re-evaluated in layered foundations. By pointing out the shortcomings and applicable conditions of the existing methods for PS testing, an improved correction equation for determining the depth of the pile bottom is proposed in a layered foundation. Whereas there are situations like the testing borehole does not meet the minimum depth requirements, or it is difficult to identify the first arrivals of parallel seismic testing signals below the pile bottom, a new method for determining the depth of the pile bottom based on identifying the traveling time inflection point of the first arrival is proposed. The result shows that the depth of the pile bottom is basically consistent with the design value. This study provides an effective means for evaluating the depth of pile bottom in the layered foundation.