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 [...]

Heavy CPT Truck Delivered to Saudi Arabian Customer (Video)

Built for Ayed Eid Al Osiami Engineering & Consulting, this heavy duty 6X6 international chassis 20 Ton CPT Truck departs our Vermont facility on August 21, 2014 headed overseas to Saudi Arabia. Contact us today to discuss your geotechincal needs. [/fusion_youtube]

What Information Should you Include in a Geotechical Report?

It could be that you've learned everything there is to know about Cone Penetration Testing, but if you don't know about geotechnical reporting, you're missing out on a big step in the process. A geotechnical report is a tool used to communicate site conditions, as well as design and construction recommendations to be relayed to personnel. In other words, you're taking the results of your CPT testing and putting them into an easy-to-understand report along with relevant conclusions. Sound simple? There's more to it than you might think. Geotechnical Report Essentials Of course, you want to include specific information in your geotechnical report like the status of substrate soil, rock and water conditions. It also goes without saying that accuracy in all areas is crucial because the data in the report will be referred to often throughout the design and construction periods, as well as after the completion of the project, primarily for resolving claims. But let's get more specific. Here are some basic must have points that should be included in every geotechnical report; keeping in mind that final content will vary somewhat depending on the business and project: Location and surface conditions: specific address, current use, surface coverings, elevation, drainage, etc. Subsurface exploration data: soil profile, exploration logs, lab or in-situ test results, ground water conditions Interpretation and analysis of data Engineering recommendations for design Anticipated problems and discussed solutions: slope stability, seismic considerations, etc. Any recommended geotechnical special provisions Include other types of geotechnical reports: foundation report, centerline soil report, landslide study report, etc. With these points as a guideline, it's possible to create a geotechnical report that covers all the right points to satisfy all parties involved in a project. This includes any government agencies that require geotechnical reports. For example, the U.S. Department of Transportation [...]

What Can You Reveal Using Fluorescence Detection?

Even if you use CPT technology daily to test soil, you may not be aware of the further advantages CPT testing has to offer beyond its more commonly used or basic geotechnical functions. Take fluorescence detection, for example. Fluorescence detection records a fluorescent response to a specific excitation of automatic carbons in a chemical. This excitation is caused by an ultraviolet light source. But you're probably wondering how fluorescence detection can help you. Read on to find out! The Common Uses of Fluorescence Detection Before delving into scenarios in which fluorescence detection is useful, let's take a closer look at how it works in relation to CPT. One method of fluorescence detection is done using handheld UV lights to investigate above ground contamination. With CPT, the UV light source is placed in the cone, with fiber-optic cables transmitting resulting fluorescence to the surface where it can be measured in voltage responses. At Vertek CPT, we use LEDs and mercury lamps to generate UV light. Whether above ground or below, fluorescence detection reveals two ranges of fluorescent emissions: 280-450 nm wavelengths and wavelengths above 475 nm. The test is capable of detecting a variety of chemicals within these ranges, including: Polycyclic aromatic hydrocarbons (PAHs) Coal tars (DNAPL compounds) if mixed with compounds, like fuels Creosote sites that contain naphtalene, anthracene, BTEX and pyrene Total petroleum hydrocarbon values (TPH) as low as 100 ppm in sandy soil Fluorescence detection is also able to detect a number of contaminants, such as jet fuel, diesel, unleaded gasoline, home heating oil and motor oil. As you can imagine, this makes fluorescence detection extremely beneficial at fuel spill sites and sites with leaking storage tanks. However, if you already use CPT testing regularly, it's worth considering fluorescence detection in other scenarios to add capability and additional [...]

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 [...]

How to Interpret Soil Test Results from CPT Testing

Even if you already have a solid grasp of what Cone Penetration Testing is and how CPT rigs test soils, understanding soil test results is a bigger task. You likely already know that CPT rigs are equipped with automated interpretation programs, but that doesn't mean test results are easily readable right away. Fortunately, even if you aren't a technician, it is possible to gain some understanding into soil test results. Read on to find out how. The basics of soil test results At the most basic level, the results of CPT testing are based on the relationship between cone bearing, sleeve friction and pore water pressure. With these three measurements, you can learn quite a bit about soil composition and conditions. For example, friction ratio measured by the sleeve is used to determine soil type. Soil is then classified according to the Unified Soil Classification System (USCS). CPT can also measure: Soil parameters Computer calculations of interpreted soil behavior types (SBT) Additional geotechnical parameters It's also possible to determine temperature shifts and zero load offset through the use of baseline readings. This essentially means comparing test results to those generated from initial testing before work begins on a site. With careful observation, it's possible to determine even more about the soil tested. Some examples include noting trends in water content to determine the type of soil (ie, sand does not retain water as well as clay) and knowing that larger values of cone resistance and sleeve friction usually indicate coarser soils, while lower values tend to indicate fine-grained soils. Although they won't put you on the level of a trained technician, these basics should make soil test results much easier to understand. More importantly, with this information in mind, you should have a much greater understanding of CPT testing as [...]

Grow your Business by Increasing your Geotechnical Services

If you're looking for ways to help grow your business, consider expanding your geotechnical services. By increasing the geotechnical services your company offers, you'll be able to expand your current client base and increase your workload. To realize these benefits, you'll first have to decide which geotechnical services you can offer, which you could offer more in-depth, how it would affect your current workload, and how it can increase your revenue. What Geotechnical Services Can your Business Offer? Rental and sales of equipment Field exploration (soil and rock sampling, test boring, core drilling, electro-magnetic surveying, etc.) Site evaluation (for pavement/ sub grades, alternative site and route studies, definition of critical geotechnical parameters) Engineering analysis and design (slope stability evaluation, hillside grading recommendations, earth retaining structure design, earthquake damage analysis) Laboratory testing services (soil classification, shear strength, permeability, consolidation characteristics, resistivity) Some of these services may be a more natural fit for your current business than others. However, it's worth considering the environment your business is located in, as well as the environmental factors that have an affect on construction. This will help you to hone in on the services that are in demand. Also research any potential competition in your area to see what they do or do not offer, and consider filling any void you discover. For example, if you notice a void in your area's laboratory testing services, consider hiring an expert internally. Between the equipment and manpower you already hold, adding an additional employee may prove profitable. If you're not sure how to gauge demand in your area, consider who you could be marketing your geotechnical services to. Potential customers include: Developers Realtors Architects Engineers Construction companies Utilities Manufacturing companies Financial institutions Federal, state and municipal organizations With a little research and a keen eye, you may [...]

Financing of New CPT Equipment Now Available

We're pleased to announce a partnership with Oakmont Capital Services as our preferred lending partner allowing Vertek CPT customers in the U.S. and Canada to enter the CPT business with as litte as no money down! Oakmont Capital Services is a full-service provider of commerical equipment financing. Application-only financing from $5,000 to $300,000 Most companies approved with 100% financing Quick turnaround on applications with most decisions made within 2 to 4 hours Competitive rates and terms (better than most banks) Financing available on new/used equipment with terms from 12 to 84 months Financing for start-up companies with a background in related industry U.S. and Canadian customers only Apply to finance your CPT purchase!

Is a Sieve Analysis Accurate?

If you regularly use Cone Penetration Testing on the job, you probably already know that there are a number of alternative soil testing methods out there. Some of the more common procedures include the Standard Penetration Test, which has been covered before in this blog, and the sieve analysis, also known as the gradation test. Most commonly used in civil engineering, this basic soil testing method is used to assess the particle size distribution of soil and other granular material. But is sieve analysis accurate? As is the case with Standard Penetration Testing, sieve analysis can provide accurate results, but only in the right conditions or scenarios. In fact, sieve analysis can achieve optimal accuracy only if certain conditions are met. First off, sieve analysis needs a proper representative example of soil from the building site, meaning particles must be mixed well within the testing sample. The sample must also be of the right size, so it does not overload the sieve and skew the results. In terms of equipment, sieve analysis requires: Test sieves that conform to relevant standards Reliable sieve shaker and analytical balance Error-free evaluation and documentation Proper cleaning and care of equipment, especially sieves When these conditions are met, it is possible to get accurate and consistent results from sieve analysis, but only with coarse materials larger than #100 mesh. When it comes to finer materials smaller than #100 mesh, sieve analysis becomes less accurate. The reason for this is the mechanical energy used to move particles through the dry sieve can compromise particle size. Fortunately, this can be offset somewhat with wet sieve analysis as long as the testing particles aren't changed by the addition of water. Sieve testing is also less accurate for non-spherical particles as they may have trouble fitting through the mesh. [...]

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.

Go to Top