Services

PENETROMETER SOIL EXPLORATION SYSTEM

STRATIGRAPHICS specializes in Cone Penetration Testing penetrometer exploration services, typically for geo-environmental and geotechnical studies. The Cone Penetration Testing penetrometer method is minimally intrusive, using a high capacity hydraulic ram to directly push small, 1.5 to 2.5 inch diameter probes into the ground without drilling a borehole. Electronic strain gage load cells mounted inside the penetrometer provide a high resolution, continuous record of the soil response to penetration. ASTM D5778 defines Cone Penetration Test (CPT) standards. In addition to CPT penetrometers with various additional sensors, we also deploy penetrometer (direct-push) soil, soil gas and groundwater samplers. ASTM 6001 describes geo-environmental applications of direct-push samplers. One of our papers is used as a reference in this document.

CPT data can be used for the evaluation of local geotechnical, hydrogeological, and qualitative geochemical characteristics. Cone Penetration Testing is more economical and quite often more accurate than typical borehole drilling and sampling because of high productivity, little or no generation of exploration derived wastes, very high data density, excellent repeatability, good practical and theoretical understanding of test results and limitations, and relative independence from operator errors. Real time display and recording of CPT data allow immediate evaluation of subsurface conditions. Well documented and widely accepted techniques allow rapid, high resolution (about 1 inch) definition of local stratigraphy. Superior evaluation of the lateral continuity of layers is routine with CPT data. Data are also typically evaluated for geotechnical parameters such as soil types, relative density, friction angles, undrained shear strengths, and equivalent SPT blowcounts.

In addition to Cone Penetration Testing penetrometers, we deploy penetrometer (direct push) samplers to sample groundwater, soil and soil gas for use in analytical testing. Direct samples confirming indirect measurements are quickly, reliably and economically obtained. We install small diameter wellpoints and piezometers for longer term monitoring purposes. We also can install up to 3 inch diameter micropiles for specialized foundation construction projects.

The most common and productive deployment platform for Cone Penetration Testing is a specially designed, ballasted truck mounted rig. These are used to house, transport and deploy the two of STRATIGRAPHICS penetrometer ssytems one 24 ton, and one 30 ton. The rigs' ballasted weight resists the thrust of the hydraulic ram.

Penetrometer sounding depths deeper than 100 feet can be regularly achieved at many sites. We have achieved depths in excess of 200 ft (+60 m) with our 30 ton rig and over 180 ft (55 m) with our 24 ton rig in the glacial soils of the Midwestern USA. Very dense sandy soils with SPT of up to as much as 80-100 blows/foot might be attempted to be explored using penetrometer methods. Our CPT production record is 1300 linear feet of CPT in one day. STRATIGRAPHICS regularly achieves rates of 400-600 ft of CPT per day.

STRATIGRAPHICS also performs Cone Penetration Testing with a rubber tracked ATV, provides CPT for overwater projects using a modular system, and has light weight systems for very soft sediment studies.