| Use: | The cone penetrometer is a truck-mounted device that rapidly penetrates the ground to collect samples. It has been used approximately 50 years for geotechnical applications, but its use in site characterization is relatively new. |
Description:
Utilization of the cone penetrometer has been the focus of both industry and government agencies which have advanced the technology for the following reasons:
The cone penetrometer typically consists of: (1) an enclosed 20- to 40-ton truck equipped with vertical hydraulic rams that are used to force a sensor probe into the ground, (2) a data acquisition, processing, and data storage computer system, and (3) electronic signal processing equipment. The cone penetrometer rod has a conical tip of up to 2 inches in diameter. It is pushed hydraulically into the ground with a maximum pressure of 80,000 pounds. As the rod progresses into the ground, a computer reads data from sensors located in both the tip and the side of the probe. The cone penetrometer can monitor for contaminants as the probe is advanced or can leave monitors in place as the rod is withdrawn. A variety of instruments can be used with the probe to make in-situ measurements.
Analytes:
| 1. Non-Halogenated VOCs | 5. PAHs | 9. Inorganics |
| 2. Non-Halogenated SVOCs | 6. Pesticides/Herbicides | 10. Explosives |
| 3. Halogenated VOCs | 7. Metals | 11. TPHs |
| 4. Halogenated SVOCs | 8. Radionuclides |
Media:
| Soil: | Ground Water: | Surface Water: | Gas/Air: |
| MINIMUM | MINIMUM | Not Applicable | MINIMUM |
This technology works most efficiently in soft soils as its reliability begins to decline in gravels. When instrumented for pore pressure measurements, subsurface hydraulic characteristics can be measured (pressure head, soil permeability, and water bearing zones), and sampling cones allow in-situ sampling of liquids and gasses.
| Maximum Depth: | <100 feet. |
| Production Rate: | Sample is available quickly. Penetration rates can be as high as 180 to 300 feet per hour, but are typically 40 to 50 feet per hour through fine-grained soils. However, adapting this tool for full use in the gravel and cobble subsurface common to arid sites will require upgrading the thrusting capacity of the truck, reinforcing tools associated with the penetrometer to withstand the additional force, and evaluating the use of vibration to facilitate penetration through gravel. |
| Investigation Derived Waste Volume: | Small volume of waste. |
| Technology Status: | Commercially available and routinely used field technology. |
| Certification/Verification: | Technology has not participated in CalEPA certification and/or CSCT verification program. |
| Relative Cost per Sample: | Mid-range expense. Operational costs are typically $3,000 per day. Operators need a minimum of two years experience on the system and experience in electronics and hydraulics. In addition, a strict maintenance schedule is required to keep the hydraulic system operable. Cone penetrometers can reduce long-term costs by limiting the amount of drilling required. |
Limitations:
ASTM Standards:
| D 3441 - 95 | Test Methods for In-situ Cone Penetration Test of Soils. |
| D 5778 | Test Methods for Performing Electronic Friction Cone and Piezocone Penetration Testing of Soils. |
| D 6067 | Guide for Using the Electronic Cone Penetrometer for Environmental Site Characterization. |
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