IMTrans recently acquired a Dynamic Cone Penetrometer (DCP), which is used to estimate strength characteristics of fine and coarse grained soils, some granular materials, and weak stabilized or modified materials. The DCP is driven into the soil by dropping either a 17.6 lb or 10.1 lb hammer from a height of 22.6 inches. The amount of penetration into the soil caused by dropping the hammer is recorded as inches/blows or millimeters/blows. The penetration and hammer blows can be recorded at certain blow counts or penetration intervals, whichever is desired. The penetration/blow is called the DCP Index (DCPI), this is the average penetration caused by dropping the 17.6lb hammer one time. If the 10.1 lb hammer is used the resulting DCPI must be multiplied by two to correct for the lighter hammer. DCPI is correlated to the in situ California Bearing Ratio, which is not the same as the laboratory soaked CBR. Examples of reduced DCP data are shown below in the two plots. One plot demonstrates the measured CBR with depth, while the other is a plot of Bearing Capacity with depth. The DCP should prove to be a useful tool for future field research projects that IMTrans will be involved in.

• Example of plotted DCP data: