In a DCP test, an 8 kg free fall hammer is lifted and dropped through a height of 575mm as shown in Figure 1. The distance of penetration of the cone tip is then recorded after every 5 blows and the cycle is repeated.
The DCP may also be referred to as a Dynamic Probe Light (DPL) which slightly departs from the European standard ISO/DIS 22476-2:2002. Both the DCP and DPL have similar energy inputs it should be noted from Table 1 that the cone diameter is significantly larger than the rod diameter for the DPL when compared to the DCP. The DPL will therefore have reduced friction acting on the rods if any friction is present. Therefore, the DCP should not ideally be undertaken over layer depths exceeding 1m, in one go (Paige-Green, 2009).
Extraction of the DCP rod by 300mm and subsequent redrive of the rod can be considered to establish friction although the cone is not disposable and therefore not entirely correct.