blow count requirement

The maximum distance a pile can move (interval distance) within a series of hammer strikes (target blows). The blow count is the number of blows of the pile hammer over a specified distance, counted throughout the placement of the pile. The target may be, for example, 50 blows in 0.25 m as the point of refusal of the pile to go deeper, i.e., the resistance target for the pile has been met (it has reached its load bearing requirement). When the blow count requirement has been met for a pile, the pile has reached its refusal point.