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Perform CPT Test to Obtain Geotechnical Data Commonly Needed for Construction Purposes

A Cone Penetration Test (CPT) is commonly used to determine the subsurface stratigraphy in situ (in place) and to estimate geotechnical parameters of the materials present. Geotechnical engineers typically use a CPT test to determine the necessary construction requirements for infrastructure – roadbeds, bridges, buildings. Due to the sensitive electronics inside the cone, it must be pushed to depth by static push methods. The CPT test method consists of pushing an instrumented cone into the ground at a controlled 2 cm/sec push rate. Common measurements being collected are cone tip pressure, sleeve friction, pore pressure and tilt angle. Additional sensors can be added like seismic, or other geo-environmental logging tools.


CPT Overview


CPT NOVA Cone

Having offered CPT equipment for decades, Geoprobe® has come to understand how innovative and ahead of their time the first generation of CPT Cones were. These independently gauged compression cones deliver high resolution digital data. The Classic line even introduced wireless transmission via sound waves. This was a very common method for years, offered as an alternative to cones requiring a cable through the push rods.

Today we offer the next generation of CPT technology - NOVA. The NOVA CPT test cone introduces higher resolution, more robust construction and improved accuracy. NOVA CPT delivers improved durability and sensitivity in an instrumented cone.

The Geotech AB NOVA CPT system has always been unique in the geotechnical industry and is known for its cordless data transmission system: a constant digital stream of data is sent to the surface through the sounding rods. No cable through the rods is needed in the cordless setup.

  • Cable CPT has always been an option, but now in Cable NOVA we can offer an entry-level cost-effective approach. 
  • Acoustic NOVA is also offered in the same form as the first-generation Classic system.  In fact, some of the same parts are still used in this mode of operation.

For more than 20 years, Geoprobe Systems® has teamed up with Geotech AB of Sweden to be the exclusive U.S. distributor for Geotech AB Cone Penetration Testing tools for geotechnical and environmental studies. We also provide the service and support, offering repair and calibration services.

The cordless or corded NOVA CPT test cones can be used from a variety of push platforms to provide continuous data, repeatable penetration results, and cost savings over traditional boring and sampling methods. NOVA Cones adhere to the national standards for construction (ASTM D-5778 Standard Test Method for Performing Electronic Friction Cone and Piezocone Penetration Testing of Soils, as well as ISO 22476-1-11:2004).

Advantages of CPT

  • There are many reasons for the widespread use of the CPT test method. Probably the most important is the in-situ measurement... it measures soil properties in the right environment; in the soil as it is, where it is. 
  • The real-time, on-site interpretation of logs can be used to better dial in the soil type, water table and soil parameters for engineering design – ultimately saving project cost.
  • Additionally, faster production rates when compared to conventional drilling and sampling result in a more cost-effective operation.
Advancing CPT test with an anchored 6712 providing equal downforce of a 20 ton press

Figure 1:

Advancing CPT test with an anchored 6712 providing equal downforce of a 20 ton press


Principles of Operation


CPT test primary measurements include tip resistance(qc), sleeve friction(fs), and pore pressure(u). Tip resistance is a measurement of soil hardness, sleeve friction is an indication of the soil cohesive strength commonly seen with clays and pore pressure is related to the pressure generated as the cone is advanced as well as an indication to the amount of clay in the formation.

The cordless CPT does not require a cable for data transmission to the surface. Inside the cone, the digital coded signal is converted to an acoustic signal which is transmitted along the steel of the drill rods to the surface. Sound signals are received by a microphone at the surface which transmits the signal to a PC via a computer interface (Fig. 2).

A corded CPT test system does not require the microphone as the data will travel through the cable to the surface computer interface and laptop computer. A simple and cost effective 4-wire cord is used in this case, connecting through a cable adapter to the CPT Cone.

Operation of an Acoustic CPT Test System

Figure 2:

Operation of an Acoustic CPT Test System


Example Logs


CPT test log showing Soil Classification, Tip (qc), Sleeve (fs), Pore Pressure (u2), and Friction Ratio (RF). Log easily shows the varying soil conditions encountered when pushing CPT in Saline County, KS. Log created using CPT-Pro (post-processing software).

Figure 3:

CPT test log showing Soil Classification, Tip (qc), Sleeve (fs), Pore Pressure (u2), and Friction Ratio (RF). Log easily shows the varying soil conditions encountered when pushing CPT in Saline County, KS. Log created using CPT-Pro (post-processing software).

CPT test log showing Soil Classification, Tip (qc), Sleeve (fs), Pore Pressure (u2), and Friction Ratio (Rf). Log clearly shows the change from clay to sand in both tip pressure and pore pressure. Note the steady increase in pore pressure beginning at 36ft., indicating the probe encountered the water table. Log created using CPT-Pro (post-processing software).

Figure 4:

CPT test log showing Soil Classification, Tip (qc), Sleeve (fs), Pore Pressure (u2), and Friction Ratio (Rf). Log clearly shows the change from clay to sand in both tip pressure and pore pressure. Note the steady increase in pore pressure beginning at 36ft., indicating the probe encountered the water table. Log created using CPT-Pro (post-processing software).


CPT-Pro Sample Log


Data interpretation software, called CPT-PRO, completes your CPT investigation.

  • Present CPT test results
  • Identify soil types using the most common CPT soil behavior classifications
  • Calculate and present Geotechnical parameters
  • Standard penetration test (SPT) blow count correlation
  • Undrained shear strength
  • Relative density
  • Friction angle
  • Coefficient of lateral stress
  • Constrained Module
CPT-PRO Data Interpretation Software:  Sample Log

Figure 5:

CPT-PRO Data Interpretation Software: Sample Log

Features & Options


CPT NOVA Cone

CPT NOVA Cone

Having offered CPT equipment for decades, Geoprobe® has come to understand how innovative and ahead of their time the first generation of CPT Cones were. These independently gauged compression cones deliver high resolution digital data. The Classic line even introduced wireless transmission via sound waves. This was a very common method for years, offered as an alternative to cones requiring a cable through the push rods.

Today we offer the next generation of CPT technology - NOVA. The NOVA CPT test cone introduces higher resolution, more robust construction and improved accuracy. NOVA CPT delivers improved durability and sensitivity in an instrumented cone.

The Geotech AB NOVA CPT system has always been unique in the geotechnical industry and is known for its cordless data transmission system: a constant digital stream of data is sent to the surface through the sounding rods. No cable through the rods is needed in the cordless setup.

  • Cable CPT has always been an option, but now in Cable NOVA we can offer an entry-level cost-effective approach. 
  • Acoustic NOVA is also offered in the same form as the first-generation Classic system.  In fact, some of the same parts are still used in this mode of operation.

For more than 20 years, Geoprobe Systems® has teamed up with Geotech AB of Sweden to be the exclusive U.S. distributor for Geotech AB Cone Penetration Testing tools for geotechnical and environmental studies. We also provide the service and support, offering repair and calibration services.

The cordless or corded NOVA CPT test cones can be used from a variety of push platforms to provide continuous data, repeatable penetration results, and cost savings over traditional boring and sampling methods. NOVA Cones adhere to the national standards for construction (ASTM D-5778 Standard Test Method for Performing Electronic Friction Cone and Piezocone Penetration Testing of Soils, as well as ISO 22476-1-11:2004).

Advantages of CPT

  • There are many reasons for the widespread use of the CPT test method. Probably the most important is the in-situ measurement... it measures soil properties in the right environment; in the soil as it is, where it is. 
  • The real-time, on-site interpretation of logs can be used to better dial in the soil type, water table and soil parameters for engineering design – ultimately saving project cost.
  • Additionally, faster production rates when compared to conventional drilling and sampling result in a more cost-effective operation.

Advancing CPT test with an anchored 6712 providing equal downforce of a 20 ton press

Figure 1:

Advancing CPT test with an anchored 6712 providing equal downforce of a 20 ton press

CPT test primary measurements include tip resistance(qc), sleeve friction(fs), and pore pressure(u). Tip resistance is a measurement of soil hardness, sleeve friction is an indication of the soil cohesive strength commonly seen with clays and pore pressure is related to the pressure generated as the cone is advanced as well as an indication to the amount of clay in the formation.

The cordless CPT does not require a cable for data transmission to the surface. Inside the cone, the digital coded signal is converted to an acoustic signal which is transmitted along the steel of the drill rods to the surface. Sound signals are received by a microphone at the surface which transmits the signal to a PC via a computer interface (Fig. 2).

A corded CPT test system does not require the microphone as the data will travel through the cable to the surface computer interface and laptop computer. A simple and cost effective 4-wire cord is used in this case, connecting through a cable adapter to the CPT Cone.

Operation of an Acoustic CPT Test System

Figure 2:

Operation of an Acoustic CPT Test System

CPT test log showing Soil Classification, Tip (qc), Sleeve (fs), Pore Pressure (u2), and Friction Ratio (RF). Log easily shows the varying soil conditions encountered when pushing CPT in Saline County, KS. Log created using CPT-Pro (post-processing software).

Figure 3:

CPT test log showing Soil Classification, Tip (qc), Sleeve (fs), Pore Pressure (u2), and Friction Ratio (RF). Log easily shows the varying soil conditions encountered when pushing CPT in Saline County, KS. Log created using CPT-Pro (post-processing software).

CPT test log showing Soil Classification, Tip (qc), Sleeve (fs), Pore Pressure (u2), and Friction Ratio (Rf). Log clearly shows the change from clay to sand in both tip pressure and pore pressure. Note the steady increase in pore pressure beginning at 36ft., indicating the probe encountered the water table. Log created using CPT-Pro (post-processing software).

Figure 4:

CPT test log showing Soil Classification, Tip (qc), Sleeve (fs), Pore Pressure (u2), and Friction Ratio (Rf). Log clearly shows the change from clay to sand in both tip pressure and pore pressure. Note the steady increase in pore pressure beginning at 36ft., indicating the probe encountered the water table. Log created using CPT-Pro (post-processing software).

Data interpretation software, called CPT-PRO, completes your CPT investigation.

  • Present CPT test results
  • Identify soil types using the most common CPT soil behavior classifications
  • Calculate and present Geotechnical parameters
  • Standard penetration test (SPT) blow count correlation
  • Undrained shear strength
  • Relative density
  • Friction angle
  • Coefficient of lateral stress
  • Constrained Module

CPT-PRO Data Interpretation Software:  Sample Log

Figure 5:

CPT-PRO Data Interpretation Software: Sample Log

If you do a geotechnical boring it requires a lot of tooling, time, work, and sweat. With CPT test it's so much simpler. We completed half the borings with cone penetration testing, which cuts time and increased profit substantially. This also provided comparable data.

- Matthew Sick, Operator, Geotechnics Soil and Material Testing, Missouri

Tooling & Instrumentation

Features of NOVA CPT

  • Wireless NOVA cone and data transmission technology makes logging quicker and easier!
  • The only CPT probe industry-wide that provides a constant stream of real-time data while you're probing... without a cord downhole. Information collected includes soil resistance on the cone tip, resistance on the outer sides, and pore pressures generated during the test.
  • The only wireless data transmission system of its kind
  • The operator does not have to manage data cable as the rods are cycled in and out of the sounding hole. Rod handling is efficient and the risk of cable damage is eliminated.
  • Data transmission methods: Acoustic NOVA, Cable NOVA.
  • Cost effective option to run cable NOVA.
  • New cone design offers 18 bit resolution with improved strength and gauge measurement accuracy.
  • Repeatable penetration results
  • Since the rod bore is free and clear, it can be used for lubrication grouting as the rods are pushed into the ground and for retraction grouting (hole sealing) as the rods are pulled. (only available by Acoustic NOVA)
  • Can be used with multiple push platforms: drill rigs, cone trucks, Geoprobe® direct push machines....
  • Interpret results quickly with user-friendly CPT-PRO software for comprehensive data evaluation.  Or by the free DI Viewer.
Acoustic NOVA and Cable NOVA Systems

Figure 6:

Acoustic NOVA and Cable NOVA Systems

There's lots more to be said about this innovative CPT equipment. To request more detailed information about how this CPT system can work for you request info from us or visit Geotech AB's website.

Seismic Cone Penetration Testing (SCPT) sounding provides a rapid and cost-effective method for directly measuring shear wave velocity of soils in situ. Shear wave velocity is used as an index of liquefaction resistance since both are influenced by many of the same factors. Alternatives to using SCPT for these geotechnical analysis can require laboratory testing or less reliable, highly empirical assessments.

SCPT shear wave velocity measurements are used in these evaluations:

  • Liquefaction risk
  • Earthquake generated ground-surface movements
  • Foundations for vibrating equipment
  • Behavior of offshore structures due to wave loading

The seismic CPT equipment is used as an add-on to our traditional NOVA CPT system. CPT data is taken in the same push that seismic information is generated.

The SCPT probe consists of a seismic section threaded to a standard NOVA CPT probe. The CPT probe records tip resistance, sleeve friction, pore pressure, and tilt angle while the seismic section is used to measure the shear wave velocities. The amount of data that is measured is too great for cordless transmission, so the SCPT probe is run with a data cable through the rods.

SCPT Benefits include:

  • Rapid, cost-effective method for measuring shear wave velocities
  • CPT coupled with Seismic CPT gives details on soil types, engineering parameters, and shear wave velocity in the same test hole
  • Seismic section is equipped with biaxially mounted geophones which provide a clear acquisition of the generated shear wave while reducing ambient noise.
  • Available in a uniaxial configuration for measuring shear wave velocity.

How does a SCPT test work?

  1. Push the seismic CPT probe to the desired test depth (shear wave velocities will be measured at multiple depths in the same push.)
  2. Generate a seismic pulse by hitting the shear plate with a sledgehammer (the hammer hitting the plate creates a vibration that moves through the soil). Data acquisition begins as soon as the hammer hits the shear plate.
  3. The shear wave travels from the shear plate, through the soil, and excites the geophones on the CPT seismic section as it moves past the probe's position.
  4. The geophone data is displayed and then stored on a laptop computer. Multiple seismic traces can be generated at each depth.
  5. Push the probe to the next measurement depth. Data is filtered and wave velocities are calculated using the SCPT software - this can be done in the field or at the office.
SCPT Test Diagram

Figure 7:

SCPT Test Diagram

Some testing applications require that the tooling is pushed into the ground instead of hammered. To do this, the power of the machine's probe cylinder is used to advance the rod string instead of energy from the hammer. To achieve any sort of depth, a suitable reaction force must be used to balance the pushing capacity of the rig. This means that you either need a really heavy rig or you need to anchor your machine.

20-ton Static Push Platform

2060CPT:

20-ton Static Push Platform

The Geoprobe® 2060CPT is a 20 ton rated static push Cone Penetration Testing platform. The hydraulic push clamp and press advance the cone with up to 20 tons of downforce. When retracting the tool string, the 2060CPT has 30 tons of pullback. A hydraulic bottom clamp keeps rods from slipping back down hole when the push clamp is released during retrieval of the tool string. An optional 6712DT mast can be mounted on the porch end of the 2060CPT. This allows for coring, conventional soil sampling, shallow drilling for soil verification, and pre-drilling.
> Learn More

Press platform (designed for 6712DT or skid steer loaders - anchored platform)

20CPT Press:

Press platform (designed for 6712DT or skid steer loaders - anchored platform)

The 20 CPT press from Geoprobe® is a flexible mast option designed specifically for performing cone penetration tests. Bracket options allow for mounting to various skid steer loaders or the Geoprobe® 6712DT. When anchored, the press has 20 tons of hydraulic downforce and 30 tons of pullback. The light weight system and small footprint allow this setup to be easily transported from location to location. This also enables the press to access sites where surface conditions will not support a larger, heavier machine.
​Learn More

Geotechnical Combo Rig (anchored platform)

3230DT:

Geotechnical Combo Rig (anchored platform)

The Geoprobe® 3230DT combo rig has the ability to efficiently sample the subsurface using both direct push and rotary drilling techniques and then quickly transition to pushing CPT tooling. Anchors are installed using the CB combo head and the CPT system is automatically pushed at a rate of 2 cm / second using the same head. With the 3230DT, drillers have multiple drilling methods at their fingertips.
​Learn More

Geotechnical Combo Rig (anchored platform)

7822DT:

Geotechnical Combo Rig (anchored platform)

The Geoprobe® 7822DT is designed to easily switch between multiple sampling and logging methods, including pushing CPT tooling.  Anchors are installed with the augerhead to provide the reaction force needed for the up to 15 tons of push typical for this platform. Using an optional head feed control kit, automatic rate control provides cone advancement at the standard 2 cm per second. Switching between drilling tasks and pushing CPT is quick on the 7822DT and only takes a few additional components.
​Learn More

Geotechnical Drilling Rig (anchored platform)

3100GT:

Geotechnical Drilling Rig (anchored platform)

The 3100GT geotechnical drill rig can be setup for CPT by using a few simple anchoring components: a rod guide, anchor, and anchor bridge. Switching from geotechnical drilling to pushing CPT is a quick and simple process. Automatic head feed rate control advances the cone at a steady 2 centimeters per second specified by ASTM Standard D5778. This provides hands-free operation during advancement of each rod.
​ Learn More

Operators of Geoprobe® Direct Image® Optical Image Profiler/Optical Image Hydraulic Profiling Tool (OIP/OIHPT) tooling can add CPT to their data stream in one of these push only tool combinations. Along with the CPT geotechnical data the operator will also collect soil conductivity with electric conductivity (EC), formation permeability measurements with HPT, and UV fluorescence of non-aqueous phase fuel hydrocarbons (NAPL) with the OIP. 

OIHPT sub with NOVA CPT lead

Figure 12:

OIHPT sub with NOVA CPT lead

The OIHPT tool allows an operator to map NAPL fuels/oils by induced fluorescence from an onboard UV LED or Green laser diode with images being captured by an onboard CMOS camera. Mapping the vertical and horizontal extents of NAPL contamination along with soil EC and HPT injection pressure provides understanding of soil types, permeability and migration pathways.                     
> Learn More: OIP

The Membrane Interface Hydraulic Profiling Tool (MIHPT) allows an operator to map dissolved phase to NAPL levels of hydrocarbon or solvent based volatile organic compounds (VOCs). Operators around the world use MIP technology to hunt out contaminant source areas and/or delineated plume extents. The coupled EC and HPT sensors again allow for the collection of soil EC and HPT injection pressure to understand of soil types, permeability and migration pathways.
> Learn More: MIP

Resources

Click on a section below to view information.

Passionate about delivering exceptional geotechnical, environmental, and instrumentation exploration services, the TERRACON CONSULTANTS INC office in Savannah, Georgia, went from being without in-house drilling resources in 2021 to running three Geoprobe®

ID: 13403 | Date:

Engineers who had gained valuable geotechnical experience working for the US Army Corps of Engineers Vicksburg District and the Waterways Experiment Station in Vicksburg, Mississippi, launched BURNS COOLEY DENNIS in 1985. Now with a staff of more than 60,

ID: 13399 | Date:

Adding 20CPT Skid Steer and CPT equipment provides economical way to gain footing in the CPT market.

ID: 12388 | Date:

Seismic CPT module offers processing and procedural advantages to maximize confidence in field testing.

ID: 12387 | Date:

Rope thread minimizes rotations required to make a joint while size fits inside 2.25-inch rod often used as a conductor casing.

ID: 5777 | Date:

Depend on Team Geoprobe®

Since 1987, Geoprobe® has manufactured innovative drilling rigs and tooling - engineered for efficiency and safety - simplifying drillers’ jobs and empowering their companies to succeed as productive and profitable leaders in the industry. When you partner with Geoprobe® you receive:

Customer-inspired Innovation

Engineering and building industry-leading drilling rigs, tooling, and techniques for the technical driller based on your needs to work safer and more efficiently.

Exceptional Value

Ensuring drilling rigs and tooling are created in conjunction – with consistent quality – to collect the highest-quality information with the most accurate result to get you to, into, and through the job efficiently.

Superior Service

Equipping you to do your best job and keeping you in the field via one-on-one expert sales and service technicians manning live support phone lines, shipping necessary parts same-day.


CPT Overview

Having offered CPT equipment for decades, Geoprobe® has come to understand how innovative and ahead of their time the first generation of CPT Cones were. These independently gauged compression cones deliver high resolution digital data. The Classic line even introduced wireless transmission via sound waves. This was a very common method for years, offered as an alternative to cones requiring a cable through the push rods.

Today we offer the next generation of CPT technology - NOVA. The NOVA CPT test cone introduces higher resolution, more robust construction and improved accuracy. NOVA CPT delivers improved durability and sensitivity in an instrumented cone.

The Geotech AB NOVA CPT system has always been unique in the geotechnical industry and is known for its cordless data transmission system: a constant digital stream of data is sent to the surface through the sounding rods. No cable through the rods is needed in the cordless setup.

  • Cable CPT has always been an option, but now in Cable NOVA we can offer an entry-level cost-effective approach. 
  • Acoustic NOVA is also offered in the same form as the first-generation Classic system.  In fact, some of the same parts are still used in this mode of operation.

For more than 20 years, Geoprobe Systems® has teamed up with Geotech AB of Sweden to be the exclusive U.S. distributor for Geotech AB Cone Penetration Testing tools for geotechnical and environmental studies. We also provide the service and support, offering repair and calibration services.

The cordless or corded NOVA CPT test cones can be used from a variety of push platforms to provide continuous data, repeatable penetration results, and cost savings over traditional boring and sampling methods. NOVA Cones adhere to the national standards for construction (ASTM D-5778 Standard Test Method for Performing Electronic Friction Cone and Piezocone Penetration Testing of Soils, as well as ISO 22476-1-11:2004).

Advantages of CPT

  • There are many reasons for the widespread use of the CPT test method. Probably the most important is the in-situ measurement... it measures soil properties in the right environment; in the soil as it is, where it is. 
  • The real-time, on-site interpretation of logs can be used to better dial in the soil type, water table and soil parameters for engineering design – ultimately saving project cost.
  • Additionally, faster production rates when compared to conventional drilling and sampling result in a more cost-effective operation.
Advancing CPT test with an anchored 6712 providing equal downforce of a 20 ton press
Figure 1: Advancing CPT test with an anchored 6712 providing equal downforce of a 20 ton press


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Principles of Operation

CPT test primary measurements include tip resistance(qc), sleeve friction(fs), and pore pressure(u). Tip resistance is a measurement of soil hardness, sleeve friction is an indication of the soil cohesive strength commonly seen with clays and pore pressure is related to the pressure generated as the cone is advanced as well as an indication to the amount of clay in the formation.

The cordless CPT does not require a cable for data transmission to the surface. Inside the cone, the digital coded signal is converted to an acoustic signal which is transmitted along the steel of the drill rods to the surface. Sound signals are received by a microphone at the surface which transmits the signal to a PC via a computer interface (Fig. 2).

A corded CPT test system does not require the microphone as the data will travel through the cable to the surface computer interface and laptop computer. A simple and cost effective 4-wire cord is used in this case, connecting through a cable adapter to the CPT Cone.

Operation of an Acoustic CPT Test System
Figure 2: Operation of an Acoustic CPT Test System


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Example Logs

CPT test log showing Soil Classification, Tip (qc), Sleeve (fs), Pore Pressure (u2), and Friction Ratio (RF). Log easily shows the varying soil conditions encountered when pushing CPT in Saline County, KS. Log created using CPT-Pro (post-processing software).
Figure 3: CPT test log showing Soil Classification, Tip (qc), Sleeve (fs), Pore Pressure (u2), and Friction Ratio (RF). Log easily shows the varying soil conditions encountered when pushing CPT in Saline County, KS. Log created using CPT-Pro (post-processing software).

CPT test log showing Soil Classification, Tip (qc), Sleeve (fs), Pore Pressure (u2), and Friction Ratio (Rf). Log clearly shows the change from clay to sand in both tip pressure and pore pressure. Note the steady increase in pore pressure beginning at 36ft., indicating the probe encountered the water table. Log created using CPT-Pro (post-processing software).
Figure 4: CPT test log showing Soil Classification, Tip (qc), Sleeve (fs), Pore Pressure (u2), and Friction Ratio (Rf). Log clearly shows the change from clay to sand in both tip pressure and pore pressure. Note the steady increase in pore pressure beginning at 36ft., indicating the probe encountered the water table. Log created using CPT-Pro (post-processing software).


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CPT-Pro Sample Log

Data interpretation software, called CPT-PRO, completes your CPT investigation.

  • Present CPT test results
  • Identify soil types using the most common CPT soil behavior classifications
  • Calculate and present Geotechnical parameters
  • Standard penetration test (SPT) blow count correlation
  • Undrained shear strength
  • Relative density
  • Friction angle
  • Coefficient of lateral stress
  • Constrained Module
CPT-PRO Data Interpretation Software:  Sample Log
Figure 5: CPT-PRO Data Interpretation Software: Sample Log


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