Geotechnical Tennessee

Soil Electrical Conductivity

In terms of measuring soil contamination, measuring soil electrical conductivity can provide useful information for a more complete site characterization study. Measuring sub-surface soil electrical conductivity is becoming less expensive as well as faster and easier. This form of measurement has most commonly been used for measuring physical and chemical soil properties but the ability to pinpoint contaminants is improving, particularly with software designed for the job. How to Measure Soil Conductivity Measuring soil electrical conductivity is facilitated by two different types of sensors, a contact sensor and a non-contact sensor. Contact sensors work by making contact with soil to measure electrical conductivity directly. These types of instruments are most often used along the surface of a field to characterize the soil for agricultural purposes. Non-Contact Sensors Non-contact sensors, as the name implies, function without having to touch the soil directly. This method is based on the measurement of the change in mutual impedance between a pair of coils passed through the soil. Electricity is applied through the coils, which creates a magnetic field. Much like the way an induction motor operates, this magnetic field induces an electrical current in nearby materials that are magnetic. You can assess the level of current induced by measuring the impedance in the operating coils. Passing non-contact sensors down a borehole has been used effectively to establish geophysical properties such as the presence of clay (which may have highly conductive materials distributed through it) and water table levels. In cases where an area is known to have contamination, the identification of clay layers and groundwater distribution can help to estimate where 'plumes' of contamination might be contained orspread underground. In the case of a borehole test, water samples can be gathered directly from discrete depths to confirm the presence of various types of contaminants. [...]

Attending CPT Symposium 2014 Las Vegas, Nevada

See The Vertek S4 Push System in Person! The 3rd International Symposium on Cone Penetration Testing will be held at the Mandarin Oriental hotel in Las Vegas, Nevada, May 12-14, 2014. The theme of the Symposium is the solution of geotechnical and geo-environmental problems using the Cone Penetration Test (CPT). We'll be at booth #1 and also setup outside with our new S4 Push System which is designed to be attached to a wide variety of equipment. Learn more about our entire line of products and data acquisition systems.

CPT Case Study: GEI Consultants

30 years of Cone Penetration Testing with GEI We're proud of the relationship we have with our long time customers. We succeed together. One of these groups is GEI Consultants, which has been delivering engineering services around the globe since 1970. Sean Brady, Senior Instrumentation Specialist with GEI, provided CPT University with background on their operation as it pertains to their CPT efforts. Briefly describe GEI’s engineering focus. What do you do for whom? GEI is a medium size engineering firm with around 700 employees in the United States. Our business line within GEI is Geo-technical, non-destructive testing, and geophysics. Our engineering’s have designed over 75% of downtown Chicago’s foundations and most of the tallest buildings in the world. We often are part of the design team when difficult and challenging soils are encountered. We perform CPT’s on earthen dams/embankments, river sediment depths, USCOE projects from Ft. Peck Montana to New York, RR alignments, bridge embankments, and Power plants. A little of everything you can imagine from Water, RR bridges, Landfills, stability of tail basins for the mines. We also oversee other companies performing CPT. We just worked in Asantana, Kazahkstan overseeing a new energy exposition 2016 project for both SPT’s and CPT. Also have overseen CPT testing in Doha, Qatar. When did CPT first become of interest and why? We have over 30 years of CPT testing experience. In the late 80’s we purchased a 30T CPT truck and traveled around the US performing CPT on challenging geo-technical projects. In the mid-90’s we sold our truck and started to perform CPT testing behind drill rigs. At the time we had a fleet of 18 drill rigs from track mounted, ATV, truck mounted, Barge mounted, etc. We get involved with delicate soils all the time. In some cases even when [...]

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 [...]

The Advantages and Disadvantages of Geotechnical Boring; Why CPT May be Your Better Option

As we noted in a previous post about Soil Quality, there are a wide range of reasons that soil needs to be tested. For some applications, it is important to get data about soil that is sub-surface, and in many cases getting data from deep under a site can be useful or essential. When most people imagine how you would gather data from soil that is deep underground, they imagine using a drilling rig of some kind. Sure enough, there are special kinds of boring tools that will let you drill deep into the ground and extract a sample of the soil at depth for analysis. Advantages & Disadvantages of Geotechnical Boring Using Geotechnical Boring, whether it be small-diameter or large-diameter equipment allows users to see the solid that is extracted. This can be useful for gaining an understanding of the sub-surface topology if a goal is to create a multi-dimensional map of the subsurface Geological conditions. There are significant disadvantages however to using Geotechnical Boring to obtain soil samples for testing. One disadvantage is that the operation of boring is for obtaining samples only, you can't gather data from the boring activity itself and therefore all of this investment in equipment, labor and time provides value only in that it presents a sample for testing. Another disadvantage is that the soil being sampled then needs to be tested using some type of laboratory equipment. This often means removing a large number of samples from the site, getting them safely in an organized way to a lab facility somewhere, hopefully nearby, and waiting for the lab results to come back. If there are apparent conflicts in data, or a particular part of the site needs more evaluation, the entire process needs to be started up from scratch again. Perhaps the [...]

CPT Testing, Part 1: Introduction to the Basic Concepts

If you have ever been curious about the Cone Penetration Testing (CPT) business, you have come to the right place. In today's post we are going to take a dive into the basic concepts and what expanding into CPT can do for your engineering business. Geotechnical Engineers and CPT Testing Geotechnical engineering is a branch of civil engineering that focuses on the engineering behavior of earth materials. Geotechnical engineers have been using Cone Penetration Testing (CPT) for over 40 years to assist in the design and construction of foundations, embankments and other structures. The standardized CPT works by pushing a 55-60 degree cone into the ground at a rate of 1-2 cm per second and is used to identify the conditions in the upper 100 feet of the subsurface. The data compiled from this testing is valuable for assessing the subsurface stratigraphy associated with soft materials, discontinuous lenses, organic materials, potentially liquified materials (such as sand, silt and granule gravel), and predicting landslides or ground settling. The cone resistance in conjunction with the friction ratio can also be used to determine soil types. While these results are often more accurate when referring to textbook soils, there are some major benefits to utilizing CPT techniques as opposed to drilling. In fact, there are a number of different advantages of CPT, including: economically friendly testing, as well as its ability to perform at a fast rate and effective in characterizing large volumes of soil without having to do a large number of laboratory testing. CPT is also accurate, eliminating the possibility of disturbances to soil samples and sample storage. By leveraging CPT results, engineers can determine the best methods for several aspects of design and construction projects. Detect lenses, thin layers and sand stringers. Evaluate the thickness and extent of compressible soil [...]

What to Consider Before Buying a Used CPT Rig

When faced with the prospect of a major purchase, it’s common to look into the possibility of buying used. In most circumstances, this is a perfectly valid option with a number of upsides, the most obvious of which being a lower upfront investment. However, when it comes to buying a used CPT Rig, you might be better off buying a new rig from a trusted vendor. Here’s why. Used Means Used First and foremost, Cone Penetration Testing is too important to leave up to chance. Sure, your used CPT Rig may appear in fine working order and you may have acquired it from a reputable seller, but there’s no getting around the simple fact that a used rig has a higher chance of failing than a brand new one. This point is further compounded when you consider the fact that even the best used CPT Rig dealer can’t match the expertise of a CPT Rig manufacturer. Expertise Straight from the Source When you buy a CPT Rig from Vertek CPT, you’re also getting access to our knowledgeable technical sales staff; something used CPT Rig sellers can’t offer. Additionally, in some instances, Vertek CPT will provide comprehensive training and will even accompany you to your first job site to maximize your chances of success. You can’t get that kind of service or expertise from a used CPT Rig dealer. Even if you think you have enough experience with CPT Rigs to ensure success with a used rig, though, it’s also worth noting that not every CPT Rig is right for every task. A Wide Variety of CPT Rigs If you have a broad enough knowledge base to feel comfortable buying and setting up a used CPT Rig, then you probably also know that there are many kinds of CPT Rigs. Cone [...]

Cone Penetration Testing Glossary of Terms

This brief glossary contains some of the most frequently used terms related to CPT/CPTU. These are presented in alphabetical order. CPT: Cone Prenetration Test or the act of Cone Penetration Testing. CPTU: Cone Penetration Test with pore water pressure measurement - a piezocone test. Cone: The part of the Cone penetrometer on which the end bearing is developed. Cone penetrometer: The assembly containing the cone, friction sleeve, any other sensors and measuring systems, as well as the connections to the push rods. Cone resistance: The total force acting on the cone, divided by the projected area of the cone. Corrected cone resistance: The cone resistance corrected for pore water pressure effects. Corrected sleeve friction: The sleeve friction corrected for pore water pressure effects on the ends of the friction sleeve. Data acquisition system: The system used to measure and record the measurements made by the cone penetrometer. Dissipation test: A test when the decay of the pore water pressure is monitored during a pause in penetration. Filter element: The porous element inserted into the cone penetrometer to allow transmission of the pore water pressure to the pore pressure sensor, while maintaining the correct profile of the cone penetrometer. Friction ratio: The ratio, expressed as a percentage, of the sleeve friction, to the cone resistance, both measured at the same depth. Friction reducer: A local enlargement on the push-rod surface, placed at a distance above the cone penetrometer, and provided to reduce the friction on the push rods. Friction sleeve: The section of the cone penetrometer upon which the sleeve friction is measured. Normalized cone resistance: The cone resistance expressed in a non dimensional form and taking account of stress changes in situ. Net cone resistance: The corrected cone resistance minus the vertical total stress. Net pore pressure: The meausured pore [...]

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 [...]

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!

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