Geologists and Geotechnical engineers provide flood risk management

Source: DVIDS - News - Geologists and Geotechnical engineers dig deep to provide flood risk management At the Arcadia flood risk management project, in Arcadia, Wisconsin, geotechnical staff are gathering data using a unique method of subsurface exploration. The Cone Penetrometer Test, or CPT, is one method used to identify and characterize soils. The CPTs were conducted with assistance from the Savannah District geotechnical and geology branch. “We benefited from their expertise and cooperation,” said Greg Wachman, senior geotechnical engineer. In CPTs, a device with a conical tip and metal sleeve measure penetration resistance as it’s pushed into the ground. Those measurements are used to characterize the soils’ engineering properties. For example, the forces on the device as it’s pushed through a soft clay are very different from those as it’s pushed through a dense sand, Wachman said. The device also records pore water pressure, which aids in understanding soil permeability and groundwater characteristics. CPTs vs. soil borings A CPT is most useful when used together with standard soil borings, Wachman explained. A soil boring drills into the ground to retrieve physical samples. In contrast, with a CPT, the soil is never seen. CPTs are significantly faster than standard borings and provide continuous test data with depth. With a soil boring, samples are collected about every 5 feet, or change in material, so it’s possible to miss important information. One limitation of the CPT, due to excessive friction, is that it may not be extended to the same depth as a soil boring. The CPTs at Arcadia are being pushed to approximately 60-70 feet, whereas a soil boring can be performed in excess of 100 feet. “By doing some CPTs next to soil borings – where we know what the soils are – we can increase the likelihood that we [...]

UNF first in Florida to conduct large-scale lab testing on sinkholes

Source: UNF first in Florida to conduct large-scale l | EurekAlert! Jacksonville, Fla. – University of North Florida researchers will be the first in Florida to conduct large-scale laboratory testing of sinkhole mechanics. Dr. Ryan Shamet, civil engineering assistant professor, was recently awarded a Florida Department of Transportation project grant for “Validation and Update of the Sinkhole Index,” a project that will aim to better understand the potential of sinkhole formation prior to any collapse at the surface. This joint project between UNF and University of Central Florida includes $90,259 for UNF and new equipment coming to UNF labs. The new equipment consists of a large-scale soil box that will allow UNF researchers to recreate and monitor the geotechnical and hydraulic mechanics of sinkholes forming in north and central Florida. The researchers at UNF and UCF will collect data from active sinkhole sites throughout the state and then refine and update analysis techniques for varying geologic conditions or regions based on their data. This analysis technique will allow engineers to quantify a location’s relative vulnerability of conditions favorable to sinkhole collapse when raveling conditions are encountered using an investigation test called the Cone Penetration Test (CPT). CPTs are a common subsurface investigation tool used by geotechnical engineers to identify soil layers and measure the strength of the soil within a project location. Through quantifying the raveling phenomenon, local engineers can better discern which mitigation techniques, such as compaction grouting or road closure, should be performed to lower the associated risk of sinkhole collapse. 

Why Are There So Many Kinds of CPT Rigs?

As you look through our website, you'll see that there are a number of different types of CPT Rigs. As you can imagine, they each have their purpose, or 'application'. In order to understand why different types of CPT Rigs exist, it's helpful to remember how CPT works in the first place. Cone Penetration Testing The goal of Cone Penetration Testing is to drive a hardened cone vertically into the the ground and to keep it moving at a specific rate of progress. The force that it takes to maintain the cone moving downward at a defined rate is an indicator of how hard the soil is at a given depth. The friction the cone sleeve encounters along the way gives us an indication of the make up of the soil. Deciding Between CPT Rigs As you can imagine, as the cone progresses further downward and encounters different types of soils, sands, clays and rocks it can take a substantial amount of pressure to keep it moving! One of the first factors that influences the design of CPT Rigs is the maximum amount of pressure that will be required to perform a specific test, to a specific depth in a given geological area. As much as 20 tons of downward force may be required to perform a broad enough range of tests to make a given rig viable for a market. For every ton of downward pressure on the test cone through the rod system, you have to have a reaction force equal to this to keep the Rig from lifting up. This means that either the Rig has to be heavier than the maximum push force, plus a safety margin, or it needs to be anchored down in some way as to reliably resist the upward force generated by [...]

The Importance of Proper Soil Quality

Sometimes it's hard to imagine how important designing the proper foundation support for a structure can be. The public may assume that the ground we are standing on is pretty much stable and should be able to hold whatever we build on it, without consideration of soil quality. However, there are examples throughout history of structures that were built upon soil conditions that were not suitable for their weight. Perhaps the most famous is the Leaning Tower of Pisa. With better soil quality, it may have been known today as the Tower of Pisa Unfortunately for the constructors, the Tower was built upon a patch of soil that was too soft on one side for the pressure the structure would exert as it's height climbed. The Tower actually had begun leaning during the construction process and had quite a tilt before it was even completed. Over time, builders began to realize that in order to build magnificent structures, and to have them endure over time, they had to understand the geology they were building on. They had to be able to translate an understanding of the soil quality that is not able to be seen into foundation designs that would support even the tallest skyscrapers we build today. Through lots of experimentation, science, engineering and creative solutions, we've been able to evolve our understanding of how to perform a variety of soil tests and how to link that to solid design and construction methods that will support structures as varied as highway bridges and high-rise buildings. As you explore the resources that we've provided in our CPT University, you'll learn about a variety of soil tests and the advantages of each. Tests such as Standard Penetration Tests (SPT), Cone Penetration Tests (CPT) and other forms of testing all have their [...]

Why Are There So Many Kinds of CPT Rigs?

As you look through our website, you'll see that there are a number of different types of CPT Rigs. As you can imagine, they each have their purpose, or 'application'. In order to understand why different types of CPT Rigs exist, it's helpful to remember how CPT works in the first place. The goal of Cone Penetration Testing is to drive a hardened cone vertically into the the ground and to keep it moving at a specific rate of progress. The force that it takes to maintain the cone moving downward at a defined rate is an indicator of how hard the soil is at a given depth. The friction the cone sleeve encounters along the way gives us an indication of the make up of the soil. As you can imagine, as the cone progresses further downward and encounters different types of soils, sands, clays and rocks it can take a substantial amount of pressure to keep it moving! One of the first factors that influences the design of CPT Rigs is the maximum amount of pressure that will be required to perform a specific test, to a specific depth in a given geological area. As much as 20 tons of downward force may be required to perform a broad enough range of tests to make a given rig viable for a market. For every ton of downward pressure on the test cone through the rod system, you have to have a reaction force equal to this to keep the Rig from lifting up. This means that either the Rig has to be heavier than the maximum push force, plus a safety margin, or it needs to be anchored down in some way as to reliably resist the upward force generated by the test (or 'sounding'). Depending upon the [...]

Ensuring That Your CPT Data is Correctly Reported and Interpreted

It is important to understand when interpreting CPT data the physics of how the data is produced. This will lead to a better appreciation of where CPT data should be validated with other types of tests in order to ensure that it is being correctly reported and interpreted. In CPT (Cone Penetration Testing), when the tip of the cone is being advanced, there is pressure exerted on the tip itself. This pressure is created from the resistance to downward force by whatever soil is resisting on the cone tip. However, this pressure is not simply exerted from the ground immediately in front of the tip. Rather, the cone forces the ground immediately in front of it to compress. This compression forces the ground in front of it to 'fail' that is, the soil cohesion is not sufficient to resist the tip load, and the soil compresses further down or moves out of the way down, sideways or a little bit away from the cone itself, upwards. Because of this movement and compression, the pressure exerted back on the cone tip is generated from a large area of soil below, around and a bit behind the cone tip itself. This means depending on soil stratification that the instruments in the tip sense soil resistance from around 5 or more cone diameters ahead and around the tip of the cone. Using a cone of 1.5 inches in diameter means that you are actually taking an average cone resistance measurement. This is sometimes called a 'tip influence zone'. If you are pushing through a sub-surface feature, such as a landslide slip face or a layer of softer clay that is a foot or less, it is quite possible to miss this feature entirely. In engineering speak, you might read something like 'exercise caution [...]

Cone Penetration Test (CPT) Overview 101

Are you new to the Cone Penetration Testing (CPT) business? Or maybe you're looking to convert your operation to CPT? Wherever your interest is surfacing from, we have everything you need to know about expanding into the CPT business with confidence. What do I get from a Cone Penetration Test (CPT)? In case you're new to the Cone Penetration Testing business, CPT will collect important subsurface information from standard tests and then from there determine important business factors, such as, how to design foundations for structures or the composition of subsurface soils. The difference between this type of data collection and other competitors is the benefit CPT has for businesses. CPT can provide immediate, onsite information that is quick and accurate. Above all, onsite results can improve your business productivity; ultimately leading to a more efficient business process. If you had the chance to take a look at our Solutions Brief: Enter the Cone Penetration Business with Confidence, then you may have already taken a deep dive into the advantages of collecting subsurface information with a process that is more quick and efficient than other options. Businesses are choosing to use a CPT solution for many different reasons; whether for construction or government purposes, they all benefit from the same advantage: speedy collection and interpretation of data, a safe solution for operators and the environment, and the ability to adapt to different weather and soil conditions. We understand how intimidating it can be to enter a new business; large or small. That's why we are focused on delivering educational content that addresses all of your CPT needs and concerns. From topics on 'What is a Cone Test' to 'Mud Rotary Drilling vs. CPT,' it's important to consider pros and cons and different scenarios in order to make the right choice [...]

Converting a Drilling Rig into a CPT Platform

If you're familiar with our CPT University blog then you may have had a chance to take a closer look into what CPT can do for your business. If you're yet to make the switch; it may be because you don't exactly have the means to support the transition into the CPT business. Fortunately, if you're still looking to reap the benefits of CPT rigs, the Vertek CPT Drill Rig Adapter may be the solution that you have been searching for. Read on to learn how you can start growing your drilling business. Converting a drill rig into a CPT platform using a Vertek CPT Drill Rig Adapter Businesses that transition out of SPT or Hollow Stem Auger Drilling are able to become more efficient and obtain a higher daily rate. How Does it Work? The drill rig CPT adapter kit enables drilling service providers to complete CPT testing with their existing equipment. So how does it work exactly? The simple adapter is first screwed onto the drill head. This enables the existing push and pull hydraulic system to advance and retract the CPT equipment to and from the subsurface. This is just a small snippet of what the drill rig CPT adapter kit can do, for even more on it's functionality, visit our drilling conversion page. A CPT Drilling Conversion Rig Kit Consists of: A Peizo-Cone Penetrometer A Data Acquisition System (DAS) and coaxial communication cable A Depth Marker for depth measurement A Drill Head Adapter for advancing and removal Rods or Rod Adapters Wear surface consumables and spares (tips, sleeves, pore pressure filters) Seismic shear wave equipment (optional) Converting a drilling rig can be a cost-effective entry into CPT. By following this route, you can enter the CPT business with a brand that offers exceptional domestic support and [...]

Towable CPT Trailer – Push System on Wheels!

New - Mount an S4 CPT Push System on equipment or a trailer! Customer response to our new S4 Push System has been very impressive. The most affordable and flexible 20 ton push system available has made CPT newly accessible to a variety of service providers around the world without the need for large dedicated vehicles. In keeping with our history of cone penetration innovation we'd proud to show off our latest improvement to the S4 Push System: Towability. That's right, the S4 can now be purchased attached to our custom trailer enabling it to be driven from job site to job site behind any full size pick-up truck. [/fusion_youtube]

Building a CPT Truck in Less Than 3 Minutes (Video)

This short video compresses about a month of construction time on a 20 Ton CPT Truck built by Vertek CPT at our Vermont facility during the summer of 2014. CPT Trucks are popular for those looking for maximum push force and all-in-one mobility. This truck will be delivered to the customer upon completion of the internal components. Large trucks provide greater push force and improved working environs while smaller trucks provide greater mobility in tight spaces. Contact us to see which is best for you. Our new S4 Push System also provides a path to entering the CPT market with limited investment. [/fusion_youtube]

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