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 [...]

Using a Compaction Test to Determine Site Safety Standards

Compaction is an engineering term used to describe the ability of a soil type to be treated with mechanical energy and compressed such that air voids are removed. With individual grains compressed to remove air voids, it becomes more difficult for the soil being compressed to 'settle' further on its own. The strength of the soil in loads other than compression can be increased because the individual particles within the soil become interlocked and friction can become a more important function of the soil behavior. Compacted soil, because air spaces between the particles are reduced has lower hydraulic conductivity (passes water less easily under a given pressure). Why do a Compaction Test? Compaction can be important when high loads such as building foundations may cause a soil to settle over time causing shifting or even collapse. It can be valuable for soil that you want to retain in place, such as along an embankment or behind a retaining wall to be compacted. The compaction process, by increasing the friction in the compacted soil helps to maintain against horizontal slippage which can either result in a landslide off from an embankment or in higher pressure behind a retaining wall, causing it to bow outwards. Because compaction lowers hydraulic conductivity, it can be useful, or even essential in the functioning of earthen dams, drainage ditches and levees. A measurement of compaction is the change in density, or weight per unit volume increase after the soil in question is compacted. That's why sometimes 'compaction' is also called 'densification'. This is actually not a correct designation as 'densification' actually includes both 'compaction' which is described above as well as 'consolidation'. Consolidation involves fluid flow out of the soil being densified, such as when you are treating clay heavy soils. Water is squeezed out from [...]

A Short Introduction into CPT and the ASTM Standards

If you have been thinking about expanding into the Cone Penetration Testing business but still need some more information to feel confident with your decision; or need further details to bring to your employer, you have come to the right place. This post is an introduction to the basics of CPT and how it correlates with the ASTM Standards to meet your needs and better serve your business. If this is the first time you have really considered entering the CPT business; CPT is the use of a hardened cone shape that is pushed into the ground to substantial depths for the process of collecting immediate onsite data. CPT has proven to be an inexpensive option that not only is safe and efficient but delivers accurate data at a faster rate. Not only is CPT an effective and inexpensive option for your drilling assignments, but it also meets the ASTM Standards, ensuring that it meets the standard of excellence (safe, quality, etc). CPT Data & ASTM Standards "ASTM International, formerly known as the American Society for Testing and Materials (ASTM), is a globally recognized leader in the development and delivery of international voluntary consensus standards. Today, some 12,000 ASTM standards are used around the world to improve product quality, enhance safety, facilitate market access and trade, and build consumer confidence" [ASTM]. To take a deeper dive into the value of ASTM Standards, take a look at this video: [/fusion_youtube]

Terracon Consulting Engineers Takes Delivery of 20 Ton CPT Track Rig

Cone penetration test rig leaves Vertek CPT's Randolph, VT facility. It can be a bit somber watching one of our CPT track rigs head out the door after spending a few months building the rig here in Vermont, but thankfully we get to work with our partners long after the sale to make sure they're successful in the field. This 20 ton cone pentration test track rig is headed to Terracon Consulting Engineers and Scientists of Olathe, Kansas. [/fusion_youtube]

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]

Incotec Q&A: Cone Testing in Bolivia

CPT in South America Vertek's S4 Push System has made entry into the CPT market accessible for a growing list of geotechnical professionals. Here on our CPT U blog we often provide a closer look at some of these organizations and how their regional markets operate. One such company is a Bolivian construction and engineering group that's been in operation since 1968, but has just recently added CPT to their offerings thanks to a Vertek S4. Read on for our Q&A with Mario A. Teceros of Incotec. Provide a brief background on your company. How/when did it originate? It was established in 1968. Is one of the oldest operating construction companies in Bolivia. It was initially created to build urban infrastructure and housing. Rapidly entered to the civil works and the deep foundations market. Incotec also started with the first geotechnical equipment (SPT and DPM) in 1968. Since then, beside the experience in different type of projects (ranging from concrete structures to industrial constructions and dams), the speciality in deep and special foundations has been the main "stamp" of Incotec. Is family company and now the third generation is working. What is the scope and focus of Incotec today? More specialization in all the fields of its activities, mainly with the incorporation of cutting edge equipments for soil tests (SCPTu from Vertek), deep foundation construction (BG18, BG20 and BG 30 from Bauer, with tools for Full Displacement Piles, Cutter Soil Mixing, cased piles) and quality controls (From Pile Dynamics, PIT, Cross Hole and PDA). But the main product developed by Incotec during the last decade is the EXpander Body, a steel folded "balloon" that is installed at the tip of a pile or an anchor. The EB is then injected with grout to expand it, compacting the surrounding soil and [...]

Geotechnical Investigation and CPT Papers Now Available From CPT ’14

Did you attend CPT '14 in Las Vegas, Nevada? If so then you know the wealth of geotechnical expertise that was shared, and if not, then be sure to examine the scope of professional papers published from the event available for review now on their website. FEATURED PAPERS Whether you are a seasoned CPT veteran or just considering entering the cone penetration profession, the topics covered at CPT '14 provide current geotechnical expertise that you can benefit from. Some of the topics covered include: The effect of sleeve diameter on fs measurements Axial and torsional axisymmetric laboratory interface shear tests for CPT attachment studies Geotechnical Offshore Seabed Tool (GOST): A new cone penetrometer Evaluating rolling dynamic compaction of fill using CPT Verification of compaction grouting program using CPT in liquefiable soils Use of CPT for stability and performance evaluation of Mississippi River Revetment slope in New Orleans Role of CPTu in design of large Atlantic port terminal in Costa Rica Use of CPT for design, monitoring, and performance verification of compaction projects Using piezocone to assess strength gain of gold tailings in semi-arid environment Interpretation of geotechnical parameters from seismic piezocone tests Novel applications of CPT for verification of ground improvement projects Fault study using CPT, drill and trenching data Shear strength evaluation of preloaded stabilized dredged sediments using CPT

What is Triaxial Testing and is it the Best Method for Testing Soil?

Those familiar with soil testing probably already know that there are a number of ways to test soil. One of the most common methods is the Standard Penetration Test, which is best known for its simplicity and versatility, but is held back by its lack of accuracy compared to more advanced options. More advanced methods include, of course, Cone Penetration Testing and Mud Rotary Drilling, both of which are common. Another common method is Triaxial Testing. What is Triaxial Testing? In order to conduct Triaxial Testing, you need a Triaxial Apparatus, which is made up of a Triaxial cell, universal testing machine and pressure control panel. For testing soil and other loose granular materials like sand and gravel, the material is placed in a cylindrical latex sleeve and submerged into a bath of water, or another liquid, which puts pressure on the sides of the cylinder. A circular metal plate at the top of the cylinder, called a platen, then squeezes the material. The distance the platen travels is measured, along with the net change in volume of the material. Like Cone Penetration Testing, Triaxial Testing is used to measure the properties of soils, but can also be used on more solid materials like rock. Typically, Triaxial Testing is used to solve problems of stability by: Determining the shear strength and stiffness of soil when retaining reservoirs of water Measuring stress/strain behavior Monitoring the internal response of the particulate medium It is also used for pore water pressure measurement and determining contractive behavior, which is common in sandy soil. As such, this soil testing method is well-suited to helping engineers improve their building designs while limiting structural/build failures by imparting a proper understanding of material behavior and an assessment of the characteristics of a build site. Primary benefits of Triaxial [...]

Should you Use a Sand Cone Test in Construction?

It may seem at times that there are almost too many soil testing methods, but many are developed to fit certain scenarios or address issues with other testing methods. This is the case with the sand cone test, which is used to determine soil compaction and is an alternative to using a nuclear density gauge. But does this mean the sand cone test is worth using when working on construction sites? The Pros and Cons of the Sand Cone Test There are many benefits to performing a sand cone test, especially for those relying on a nuclear density gauge. With a sand cone test, you can get similar results at a much lower cost, without the need for radioactive material. The cost of the sand cone test apparatus is also fairly low, making sand cone testing relatively inexpensive. The apparatus consists of a plastic container, a metal cone with a valve and a high density base plate. Its also relatively small and portable, making testing possible pretty much anywhere. The sand cone test has its fair share of negatives as well, including: Easy to compromise samples during testing. Soil samples are sensitive to vibrations, shifting of particles, and any errors in set up of the test site Samples that contain mixed particles can be less accurate Samples that contain too much moisture content can be less accurate Long result time: 20 minutes (vs. nuclear gauge which only takes 1 minute for results) Technicians, of course, should be aware of the limitations of the sand cone test as many factors can skew its results. In other words, the sand cone test may not be worth using when working on construction sites, except to confirm observations and inform opinions about soil moisture and density. This is especially true when you consider that [...]

CPT Mini Track Rig – Our Most Compact Self-Powered Rig

New – The Mini-Track Rig provides all-terrain performance at an affordable capital cost! The latest addition to Vertek's robust line of self-propelled CPT rigs harnesses the popular 20-ton S4 Push System in a small but versatile package. This rubber-tracked rig is easy to maneuver, ideal for limited access areas, and maintains a low ground pressure of 4.5 psi. The S4 Mini-Track Rig provides a powerful carrier at an affordable price when compared to the cost of new construction equipment. Is the Mini-Track Rig right for your application? The Mini-Track Rig is ideal for situations where agility and low ground pressure are important At only 10.5 feet long, it can be transported to job sites with a pick-up and trailer The S4 CPT system's tilt mount increases stability on uneven terrain and provides a low profile during transport The S4 can be removed and attached to construction equipment or custom trailers, allowing for any number of configurations The Mini-Track Rig is available with many options to meet all your testing needs. Though small and light, the Mini-Track Rig provides convenience and functionality similar to Vertek's larger purpose-built CPT rigs. Optional features include: Mechanical or Hydraulic Clamp Diesel or Gas Engine 300,350,400, or 500 mm Anchor Decontamination System Remote Operation 120V AC Inverter Rod Rack For a full list of features, specifications and technical data, visit vertekcpt.com or download our full catalog of Geotechnical and Environmental products.

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