DCP (Dynamic Cone Penetrometer) Testing
The DCP unit has been used to identify weak subsurface soils to depths of 30 plus
feet for over 15 years in the United States. U.S. applications for this device have
included evaluations of pavement systems, building foundation systems, and
increased bearing capacities.
Another benefit to the DCP is its small foot print and relatively lightweight design.
This allows it to be used in confined areas such as inside buildings (to evaluate
foundation settlements) or on congested sites (trees, steep topography, soft soils,
etc.)
DCP Function
• Prior to performing DCP testing, utilities must be identified.
• A 3.81 cm (1.5 inch) diameter hole is drilled in the pavement.
• A sacrificial cone and rods (incremented every 10 cm or 3.937 inches) are inserted into the hole.
• The cone and the rods are driven into the soil by a percussive head (weighing 30 kg or 66 pounds) dropped 20 cm
(7.874 inches). The percussive head is lifted by a mechanical arm driven by an electrical motor.
• The number of drops of the percussive head required to drive the rod 10 cm (3.937 inches) is recorded.
• These blow counts provide information about soil strength. Moreover, these blow counts can be correlated to the
N-value associated with the Standard Penetration Test (SPT) by using a relationship developed by the
manufacturer: N (SPT) = 0.766 x N (DCP)
Specification - DPM 30-20 Model DCP
• Manufactured by Pagani Geotechnical Equipment of
Piacenza, Italy
• Diameter of Cone Tip = 35.6 mm (1.40 inches)
• Angle of Cone Tip, B = 60 degrees
• Area of Cone Tip, A = 10 square cm (1.55 square inches)
• • • Diameter of Rods = 20 mm (0.7874 inches)
Length of Rods = 1 m (39.37 inches)
Weight of Rods = 2.4 kg (5.29 pounds)
• • Weight of Drop Hammer = 30 kg (66 pounds)
Free Fall Drop Height = 20 cm (7.874 inches)
The DCP data is recorded to a spread sheet with a graph indicating levels of weak soils. Multiple tests can be grouped
together to provide an average N-value for the area.
Advanced Materials, LLC ® -­ P.O. Box 3414, Dublin, OH 43016 – 614-­561-­6440 [email protected]