cpt applications

Subsurface sediment stability is one of the most essential factors in the design and construction of any foundation, whether it be a natural feature like a riverbank or a manufactured structure like a building. The composition of the sediment, as well as its density and moisture content, all play a role in how stable a foundation will be. Cone Penetration Testing, or CPT, is an and easy and efficient subsurface investigation method that can be leveraged to assess the stability of sediment to ensure a foundation is properly supported. 

Why Cone Penetration Testing? 

CPT is a relatively non-invasive way to test the stability of a foundation, and it can be used in both natural and human-made settings. CPT involves advancing a probe into the ground at various depths and collecting data about the sediment at intervals as close as three millimeters. This data is then analyzed by engineers and contractors to determine what remediation needs to be done. 

In the case of river erosion, CPT can be used to assess the stability of the sediment along the bank. This is important because river erosion can pose a severe threat to both public safety and the environment. By using CPT, engineers can determine if the sediment is stable enough to support the weight of the bank or if it is susceptible to erosion. This saves projects money by avoiding high human and financial costs associated with failed riverbank stabilization. This is also important because river erosion can seriously threaten public safety and the environment through things like flooding and landslides. Vertek offers a variety of low ground pressure tracked CPT systems that are designed to access sites with loose sediment like riverbanks and nearshore beaches. 

Mitigating Risk with CPT 

Using CPT, engineers can avoid costly repairs by identifying ground instability that can pose a threat to humans, infrastructure, and/or the environment. According to the U.S. Environmental Protection Agency: 

“Increased sediment and erosion in rivers, lakes and streams can also affect water quality and availability of drinking water sources. For example, increased sedimentation can affect the storage capacity of reservoirs and increase the need for treatment at water utilities.” 

Further, the British Geological Survey reported in 2022: 

“Recent studies have shown that, in the UK, river erosion and associated impacts exacerbate flood damage by £336 million ($410 million USD) a year and are a considerable source of water pollutants, costing £238 million ($290 million USD) a year to remediate. River erosion further increases the costs of water treatment and maintenance of drainage networks by £132 million ($161 million USD) a year and accounts for 25 per cent of valid subsidence insurance claims (Li et al., 2021, Pritchard et al., 2013).” 

Thanks to Vertek’s high-efficiency CPT systems, operators can conduct multiple site investigations over a wide area in a single day. This allows engineers to get a full picture of the subsurface area in question in a short amount of time.  

Choosing a Trusted Partner 

With nearly 40 years of experience working with government agencies, drilling companies, and engineering firms, Vertek is your go-to source for all things Cone Penetration Testing. Based on your scope of work, we can help you determine the best CPT system to get the job done.

Contact us today to discuss your needs and our solutions.  

Dams and levees are essential to our society. They protect us from floods and other natural disasters, and the consequences can be disastrous if they fail. Cone Penetration Testing, or CPT, is a subsurface investigation method that can be used to determine the strength and stability of the ground supporting these massive structures. This high-resolution data can help geotechnical engineers identify potential problems and implement mitigation strategies. Keep reading to learn how you can leverage CPT to support the nation’s infrastructure and expand your business.

The Benefits of Cone Penetration Testing

CPT involves statically advancing a sensored probe with a conical tip up to hundreds of feet (or less) below the ground subsurface to collect in-situ readings of three main measurements: tip resistance, sleeve friction, and pore pressure. These measurements can then be used to determine the sediments strength and the structure’s stability by calculating several values which can generate a soil behavior type. You can learn more here. CPT is not only efficient and effective, but also much faster and is less disruptive than traditional drilling methods.

Vertek offers low ground pressure systems such as our tracked CPT systems and S4 CPT Sounding System that are ideal for such areas. The S4 is particularly popular among new and experienced CPT operators because it can mount to a variety of standard construction equipment equipped with auxiliary hydraulics.

Using Cone Penetration Testing to Support Dams and Levees

When constructing dams or levees, whether for a new project or the evaluation of an existing structure, a CPT investigation can be used to determine the subsurface sediment strength and the structure’s stability. This information is essential for ensuring these structures are safe and still sound to withstand tremendous loads from climatic events.

With the recent $3 billion investment by the federal government for dam-related projects, there will be a great need to conduct sensitive subsurface investigations to understand and evaluate these structures and if risk mitigation efforts are necessary. The U.S. Army Corps of Engineers and Bureau of Reclamation for example uses Vertek CPT systems to assess dams and levees around the U.S., This work will continue to expand to geotechnical firms and drilling companies in the years ahead.

Learn more about the business of CPT with our free guide and download our ROI calculator to see how fast you can earn a return on your investment. Have questions or ready to purchase? Reach out to us here.

Ground improvement and stabilization are two important aspects of any construction or engineering project. When it comes to ground improvement, several different techniques can be used, which can be complex and require a high degree of precision. Cone penetration testing (CPT) and ground improvement are becoming synonymous as more engineering firms and government agencies adopt CPT.

Any error or inaccuracies can lead to severe problems down the line. That’s why businesses that work in this field need to have a robust quality assurance and quality control (QA/QC) program in place. Many different products are available to businesses in the ground improvement and stabilization field, but CPT is one of the most accurate and efficient methods available to characterize the density of the sediments.

Vertek offers a wide range of CPT systems used to conduct in-situ testing for soil strength and cohesiveness. The system consists of a sensored probe with a conical tip that collect and measure three main measurements: tip resistance, sleeve friction, and pore pressure. With these series of sensors, you can calculate:

● “N”-value

● Overburden

● Effective overburden

● Undrained shear strength

● Over consolidation ratio

● Friction angle

● Pore pressure ratio

● Coefficient of earth pressure

● Young’s Modulus

● Poisson’s Ratio

● Relative density

● Hydraulic conductivity

● Normalized uncorrected tip stress

● Normalized corrected tip stress

● Normalized friction ratio

● 1986 friction ratio behavior type

● 1990 friction ratio soil behavior type

● Preconsolidation stress

● QCI

● Fines content

● Classification index

The Need for Ground Improvement and Stabilization

Ground improvement is improving the mechanical properties of existing soils or fill material. It can also be improved through the use of prefabricated piles and structural material replacement. This can be done through a variety of methods, such as:

● Vibro Compaction

● Vacuum Consolidation

● Preloading of soil

● Soil stabilization by heating or vitrification

● Ground freezing

● Vibro-replacement stone columns

● Mechanically stabilized earth structures

● Soil nailing

● Micro-piles

● Grouting

In construction and engineering projects, ground improvement helps to ensure the ground on which the project is built on can withstand things like seismic events, creation of deep foundations for superstructures, and land expansion into bodies of water. Similarly, ground stabilization improves soil stability and can be achieved through multiple different methods. That’s why businesses need to have a strong QA/QC program in place to define and validate ground improvement activities through the ground improvement cycle. If not appropriately managed, improper ground improvement and stabilization can lead to problems, such as:

● Erosion

● Pipe breaks or leaks

● Damage to underground utilities

● Sinking or settling of the ground

● Failure of retaining walls or other structures

If you do not utilize CPT as part of your site investigation or QA/QC program, you could be at a greater risk of experiencing one of these issues. All these problems can be costly and time-consuming to fix, but by utilizing CPT, businesses can avoid these problems and ensure that they know the subsurface characteristics of the ground they are building on.

The quality assurance and quality control of ground improvement and stabilization are essential to the success of any project. We hope you can see the value of cone penetration testing and ground improvement. Vertek can help you ensure the quality of your project and avoid potential problems. If you have any questions about our product or how it can benefit your business, please don’t hesitate to contact us. We would be more than happy to discuss your needs and our solutions.

Vertek equipment is proudly designed, manufactured, and serviced in the United States. As former CPT providers, we know the importance of having reliable support while you are in the field, and it’s why we are always just a phone call away for the life of your equipment.

Cone penetration testing (CPT) is an advanced site investigation method for assessing and recording the properties of sediments. The field test involves the use of a static hydraulic advancement system to slowly advance a probe equipped with multiple measurement sensors into the sediment directly below.  The CPT system collects and records high resolution data to determine site characteristics such as density, shear strength, soil behavior type, and other derived properties. The data is then analyzed by engineers to understand what improvements need to be made to support the proposed load bearing structure.

A lesser-known application for CPT is the investigation of coal-fired power station by-product deposit sites, sometimes referred to as “coal ash ponds.” Keep reading to learn why CPT is a great method for investigating these sites.

How CPT Testing is Helpful

Coal ash can take many forms, including solid particles, liquid slurry, or gas. Coal ash is often disposed of in large ponds enclosed by earthen dams, which can be a potential hazard if the material is not homogenous, or the confining dam fails. As one might expect, coal waste sites are highly regulated by the U.S. Environmental Protection Agency (EPA) and require investigation to evaluate the overall site’s stability and failure risk. By understanding the composition and strength of coal ash and confining structures, geotechnical engineers can make informed decisions and predictions based on collected site data, such as how sediment may behave during an earthquake or severe weather event and what risk mitigation efforts should be implemented preventing catastrophic damage.

CPT site characterization allows engineers to measure high resolution sediment characteristics safely and efficiently with minimal disruption to subsurface material. Measuring sediment properties in-situ, or “in the original place,” is important as it gives engineers the most accurate assessment of what is deposited at specific depths. Other, more invasive testing methods may disrupt the soil enough that the collected samples are not an accurate reflection of the in-situ sediment conditions.

CPT Systems

CPT is an effective and easy way to investigate subsurface conditions of coal ash deposits as shown above. However, not every CPT system is the right fit for coal ash and other waste sites.

Vertek’s S4 CPT Sounding System offers modularity and can be used with a wide track skid steer to provide low ground pressure footprint and lower capital investment. The benefit of the S4 is that it can used as needed on a site and be adapted to common construction equipment via quick attach or mounted to a custom self-sufficient trailer.

Vertek’s Track CPT Systems offer the ability to have a powerful track-mounted CPT system that also offers low ground pressure and built for high levels CPT production testing. With a lighter and distributed footprint, these track systems are ideal for navigating less stable ground.

As former CPT providers, Vertek builds systems that provide the reliability and ease of use we would want and demand from a system. With less than a day of training, we can have you up and running. Contact Team Vertek to discuss your needs and our solutions.

Geotechnical testing is performed by geotechnical engineers, geotechnical technicians, or engineering geologists to understand the characteristics such as the physical properties that exist underneath a work site.

An essential part of the planning and constructing building and infrastructure projects (comprising various types of structures as a foundation, roads, bridges, excavation pit, land reclamation, beach nourishment, etc.) is the knowledge of the subsurface conditions.

The geotechnical investigation with its respective services shall be carried out. Their nature and extent depend on the structure’s type, the size of the structure, and the expected ground conditions.

Geotechnical testing is conducted by site characterization, laboratory testing, and professional interpretation of data obtained to complete the design and construction of the site improvement.

Tests generally fall into 4 categories, test pits, trenching, boring and in situ testing.

Test Pits

Test pits are much like you would expect, a pit is dug either manually or with an excavator in order to reveal the subsurface conditions to the depth desired. Generally, this is for siting shallow foundations.

Trenching

Trenching is similar to test pits except that in this case, the pit is elongated over some distance in order to establish how the subsurface conditions change over various parts of the worksite. This method allows for identification of different sedimentary changes over a longer distance.

A range of soil samplers can be used to extract test samples from these test pits for lab analysis and visual identification.

Boring

Borings, usually deployed by a drill rig and drill crew, can vary in diameter and provide the opportunity to assess density through standard penetration testing (SPT) to physically remove soil or rock samples for assessment and testing.

Borings provide the advantage of assessing field density and letting you observe the actual materials extracted. Generally, soil samples from the above tests are taken to a lab where they are evaluated. Borings offer you the opportunity to set piezometers to assess groundwater table seasonal fluctuations.

In Situ Testing

In situ testing methods include penetration tests such as Standard Penetration Tests (SPT), which penetrate via drilling, percussion-based investigation techniques, sonic vibratory drilling methods, and various static direct push Cone Penetrometer Testing (CPT).

In situ testing provides the advantages of generating a more accurate assessment of subsurface conditions allowing for better data analysis and informed geotechnical design.

The right test should be specified for the right situation or utilizing multiple tools to develop an accurate assessment of the subsurface strata. Understanding the different types of testing methods available and the advantages of each can significantly reduce uncertainties and future construction.

If you are unfamiliar with CPT, you can help your clients to understand the advantages of CPT data and expand your business by offering these services. Your clients will be able to reduce their construction risk and cost by having high resolution data, reducing their uncertainty in the subsurface conditions they may encounter.

The other investigation methods have their purpose and capabilities just as CPT does. However, CPT offers a safe, high production, high resolution data set that other methods do not.

For instance, Vertek’s Heavyweight CPT Truck is the most efficient way to collect CPT data. With a powerful seismic beam, easy to use controls, and climate-controlled cabin, this Heavyweight CPT Truck can take your site investigation business to the next level.

If you are interested in expanding your business to offer various exploration methods, CPT offers a great subsurface tool with a quick return on investment. Check out Vertek’s product page to explore what we offer.

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