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Soil Quality in Geological Engineering

Agronomists, Civil Engineers, Geological Engineers and more will often talk about 'Soil Quality'. As a result, there can be varying definitions of what 'quality' soil means. That means that there are a wide variety of tests to determine 'Soil Quality'. What Does Soil Quality Mean for You? For the Agronomist, Soil Quality refers to the capacity of soil to provide a kind of function related to growing capacity. This will take into account the soils ability to support life as in its chemical properties (does it have enough nitrogen etc.), it's biological properties (does it have the right bio-system to support the production of certain types of crops), will it retain the right amounts of water, is it's grain size suitable for tilling etc. There are many tests that will help one to evaluate the agricultural viability of soils. For the Civil and Geological Engineer some of these tests might be valuable. For instance, in making recommendations in how to reclaim a 'brown field' (a site that was formerly industrial that is now being re-developed for other purposes) it can be useful to identify the level of ability of an area to support specific types of grasses. When performing earthworks, it is not uncommon to use plantings such as trees as part of the anchor system to help to hold berms and such in place. Knowing Soil Quality in this respect can help to support a good decision with respect to the structural support that a living ecosystem can bring. Generally though, Engineering types are after more specific physical properties in order to 'do the math' on how an engineered system will interact with the soil conditions that are present. This enables engineers to either recommend changing the systems in place (such as by excavating large quantities of soil out, [...]

By smadi66|December 4th, 2019|Introductory, Soil Testing, Geotechnical Louisiana, Geotechnical Maine, Geotechnical Kentucky, Geotechnical Massachusetts, Geotechnical Michigan, Geotechnical Missouri, Geotechnical Maryland, Geotechnical Minnesota, Geotechnical Kansas, Geotechnical Mississippi|0 Comments

New Geotechnical Exploration Firm in Southeast US: PalmettoINSITU

Vertek S4 Push System In Action Extracting underground data to determine soil parameters in order to efficiently provide foundation requirements Vertek customer Michael Cox has launched PalmettoINSITU, LLC, a geotechnical exploration firm specializing in extracting and presenting more exact data from coastal, southeastern, and southwestern soils prior to development and construction projects. Geotechnical engineers will contract with PalmettoINSITU to extract underground data to determine soil parameters in order to efficiently provide foundation requirements for: Bridges, multi-story buildings, private residences, nuclear power plants, wind turbines, cellular communication towers, municipal water tanks, water treatment facilities, sinkholes, profiling top-of-rock, directional boring, and many other critical applications prior to development and construction. About Michael Cox: Michael Cox spent 13 years with S&ME, a global Top-100 engineering firm before launching PalmettoINSITU in June of 2014. Michael Cox graduated from Florida Institute of Technology with an MS in Information Technology and a BS in Computer Information Systems. Cox also earned an AS in Civil Engineering Technology, including AutoCAD and Surveying certificates from Trident Technical College in Charleston. Michael Cox is known as the "Indiana Jones" of capturing soil data in the geotechnical engineering space, due to his reputation and innovation for getting in and out of some of the most challenging site locations. Before beautiful residences, commercial buildings, or major facilities are built, their raw land is typically rough, wooded, wet, or otherwise a challenge to physically enter in order to begin testing the soil. Vertek's S4 Push System offers maximum flexibility to access these site locations due to application on a variety of equipment. Michael Cox earned over a decade of geotechnical experience working on the following projects: Norfolk Naval Shipyard (Virginia), Andrews Air Force Base (Maryland), The Boeing Facility (South Carolina), The Bellefonte Nuclear Station (Alabama), Robinson Nuclear Power Plant (South Carolina), The Google [...]

By smadi66|December 3rd, 2019|Geotechnical Maine, Geotechnical Massachusetts, Geotechnical Michigan, Geotechnical Montana, Geotechnical Missouri, Geotechnical Maryland, Geotechnical Minnesota, Geotechnical Mississippi, Geotechnical Nebraska, Soil Testing, Vertek Partners, Geotechnical Louisiana|0 Comments

CPT Testing 101: Basic Concepts

A Cone Penetration Test is used to collect key subsurface information from soil by pushing a hardened cone shape per ASTM International standards, deep into the ground with the help of steel rods, a hydraulic ram and, in most cases, a very heavy truck. CPT is typically used to determine the composition, distribution and strength of soil, sediment and other geological subsurface features like clay, sand, bedrock and even contaminants. The information gathered by Cone Penetration Testing can be used to inform important business decisions, like how to design the foundations of a structure. This helps prevent any future issues that could arise from building a structure blind. Of course, CPT testing isn’t the only method of soil investigation, but it is among the most commonly used and accepted, and for good reason. For starters, CPT testing offers quick collection and interpretation of field data; in fact, it is up to three times faster than traditional methods. In addition, CPT testing eliminates drill cuttings, while also being economical, environmentally friendly, safe and adaptive to various weather and soil conditions. In other words, CPT is the clear, superior choice for soil testing in the majority of situations. Best of all, thanks to developments like Vertek’s S4 Push System, it’s possible to perform CPT testing with nothing more than the CPT System and a commercial skidsteer. For a closer look at how CPT stacks up against competing methods of soil investigation, check out our ‘Mud Rotary Drilling vs. CPT’ post. If you're still curious about what expanding into the CPT business can do you your business, subscribe to our blog, or take a closer look at the video below! [/fusion_youtube]

By smadi66|December 3rd, 2019|Geotechnical Nevada, Geotechnical New Hampshire, Geotechnical Michigan, Geotechnical Missouri, Geotechnical Maryland, Geotechnical Minnesota, Geotechnical Mississippi, Geotechnical Nebraska, Introductory, Geotechnical Massachusetts, Geotechnical Montana|0 Comments

CPT Testing, the Piezocone and Measuring Soil Moisture

When you think of Cone Penetration Testing (CPT) you may tend to focus on the soil being tested, which makes sense since soil testing and analysis is largely what CPT is all about. But let’s not forget another equally important aspect of soil testing: moisture. While measuring soil moisture levels isn't necessarily important in every investigation, it is often valuable information to have for your data set. When designing underground electrical equipment or digging tunnels, for example, knowing soil moisture conditions at certain depths is crucial. Measuring Moisture with a ‘Piezocone’ Measuring the moisture content of soil is a crucial aspect of CPT that is performed by a type of cone known as a ‘Piezocone.’ The Piezocone is a core component of many CPT systems; in fact, it’s actually a type of CPT cone. Able to measure the presence of groundwater, the Piezocone is fitted with a device that measures in-situ pore pressure. As such, when the cone penetrates into soils, water pressure is exerted on and measured by the Piezocone. Pore pressure data is recorded automatically during the testing process. As with any standard Cone Penetration Test, the Piezocone also measures pore pressure tip resistance, sleeve friction to provide a picture of the soil behavior being tested. Due to its relatively specialized nature, the Piezocone is typically used when soil conditions are expected to be fairly wet. The Piezocone is a standard configuration of most CPT cones while adding the ability to measure a greater breadth of information. If you found today's post interesting, subscribe to our blog for even more on the CPT business!

By smadi66|December 3rd, 2019|Geotechnical New Jersey, Geotechnical New Mexico, Geotechnical Michigan, Geotechnical Missouri, Geotechnical Minnesota, Geotechnical Mississippi, Geotechnical Nebraska, Introductory, Geotechnical Montana, Geotechnical Nevada, Geotechnical New Hampshire|0 Comments

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]

By smadi66|December 3rd, 2019|Geotechnical New York, Geotechnical Missouri, Geotechnical Mississippi, Geotechnical Nebraska, Geotechnical North Carolina, Video Posts, Geotechnical Montana, Geotechnical Nevada, Geotechnical New Hampshire, Geotechnical New Jersey, Geotechnical New Mexico|0 Comments

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 [...]

By smadi66|December 3rd, 2019|Geotechnical Michigan, Geotechnical Massachusetts, Geotechnical Missouri, Geotechnical Maryland, Geotechnical Minnesota, Geotechnical Kansas, Geotechnical Mississippi, CPT Data, Introductory, Soil Testing, Geotechnical Louisiana, Geotechnical Kentucky, Geotechnical Maine|0 Comments

CPT 101: Determining Soil Profiles from CPT Data

Cone Penetration Testing allows the tester to identify the nature and sequence of subsurface soil types and to learn the physical and mechanical characteristics of the soil – without necessarily taking a soil sample. How does it work? During a CPT test, a hardened cone is driven vertically into the ground at a fixed rate, while electrical sensors on the cone measure the forces exerted on it. The zone behavior type of the subsurface layers can be extrapolated from two basic readings: cone or tip resistance and sleeve friction. Cone Resistance, denoted qc, represents the ratio of the measured force on the cone tip and the area of the normal projection of the cone tip. The cone resistance indicates the undrained (i.e., including in-situ moisture) shear strength of the soil. Sleeve Friction, denoted fs, is the friction force acting on the sleeve divided by its surface area. The relationship between these two measurements is expressed in the Friction Ratio, denoted Rf and given as a percent. It is the ratio of the sleeve friction to the cone resistance. High friction ratios (high friction, low cone resistance) indicate clayey soils, while low friction ratios indicate sandy soils. The relationship between friction ratio and cone resistance is the simplest method of identifying soil strata with a CPT system, and is especially convenient because the soil behavior type can be extrapolated immediately as the data is collected. An example soil classification chart is given below (though this example uses the corrected cone ratio qt, which we’ll discuss in another blog). As you can imagine, several factors can affect the accuracy of these predictions, for example: Overburden Stress: the pressure exerted on a substrate by the weight of the overlying material Pore Water Pressure: the pressure of the groundwater in the gaps between soil [...]

By smadi66|December 2nd, 2019|Geotechnical Mississippi, Geotechnical Nebraska, CPT Data, Introductory, Cone Penetration, Geotechnical Louisiana, Geotechnical Maine, Geotechnical Michigan, Geotechnical Massachusetts, Geotechnical Missouri, Geotechnical Montana, Geotechnical Maryland, Geotechnical Minnesota|0 Comments

CPT 102: Common Corrections in CPT Data Analysis

In a previous blog, we discussed the pore pressure sensor that is common to most modern CPT cones and briefly introduced why this reading is helpful in soil profiling. Today we’ll take a closer look at how pore pressure data is used to correct and analyze CPT data. Pore pressure data is used to correct or “normalize” sleeve friction and cone resistance readings in the presence of in-situ moisture and overburden stress. This is especially important in soft, fine-grained soils where in-situ moisture takes longest to dissipate, and in tests at depths greater than 100 feet. Corrections based on pore pressure data also help standardize soil behavior type characterizations when CPT cones of different shapes and sizes are used. How are these corrections calculated, and how do they work? Correction of cone resistance data: The corrected cone resistance, qt, corrects the cone resistance for pore water pressure effects. qt = qc + u2(1 - a) qc = cone resistance u2 = pore pressure measured directly behind the cone a = cone area ratio (this value is dependent on the design and geometry of the cone, and is determined via lab calibration) Corrected cone resistance is used in calculating the normalized cone resistance, Qt, which indicates the cone resistance as a dimensionless ratio while taking into account the in-situ stress: Qt = (qt – σvo)/ σ′vo σvo = total vertical stress σ′vo = effective vertical stress (the stress in the solid portion of the soil – in other words, the total vertical stress minus the stress due to in-situ water and air) Some geologic knowledge of the test site – for example soil unit weight and groundwater conditions – is necessary to estimate σvo and σ′vo. Correction of sleeve friction data: Sleeve friction data is sometimes corrected for the effects of [...]

By smadi66|December 1st, 2019|Geotechnical Nebraska, CPT Data, Introductory, Geotechnical Maine, Geotechnical Massachusetts, Geotechnical Montana, Geotechnical Michigan, Geotechnical Nevada, Geotechnical Missouri, Geotechnical Maryland, Geotechnical Minnesota, Geotechnical Mississippi|0 Comments

CPT Dictionary: Overburden Stress

Overburden stress, also called vertical stress or overburden pressure, is the pressure imposed on a layer of soil by the weight of the layers on top of it. Overburden stress can cause errors or drift in CPT measurements, creating the need for correction factors in deeper tests depths and soft or fine-grained soils. However, overburden stress is also useful in determining the soil’s mechanical properties. In this blog, we’ll give an overview of the effect of overburden stress on CPT testing and what we can learn from it. The formula for overburden stress is given by: σvo = overburden stress ɤi = in situ density of soil layer hi = height of soil layer If it’s been a while since you’ve seen summation notation, this means that for each soil layer, you multiply the density of the layer by its height, then add all the resulting weights together until the pressure at the desired depth is known. In practice, the exact height and density of the soil layers at the test site are usually not known, so you may have to determine an average density based on what you do know about the geology of the area. CPT measurements of tip resistance, sleeve friction and pore pressure tend to increase along with increasing depth and increasing overburden stress. This effect can be seen in the graph at right. For this reason, we correct for overburden stress in calculating the normalized friction ratio and normalized tip resistance: to ensure that your data is consistent, it is important to use these parameters in deep tests and in soft, fine-grained soils, as we discussed in an earlier blog. In addition to normalized CPT parameters, overburden pressure allows us to understand and calculate the following engineering parameters: Effective overburden stress: the effective stress on [...]

By smadi66|December 1st, 2019|Geotechnical Massachusetts, Geotechnical Montana, Geotechnical Nevada, Geotechnical New Hampshire, Geotechnical New Jersey, Soil Testing, CPT Dictionary, Geotechnical Michigan, Geotechnical Missouri, Geotechnical Minnesota, Geotechnical Mississippi, Geotechnical Nebraska|0 Comments

Data Analysis With DCP

DCP (Dynamic Cone Penetration) Testing is a simple, reliable and cost-effective method to evaluate the in-situ stiffness profile of soil to a depth of about three feet. Its extreme portability, minimal disturbance of the subgrade, and ability to produce a continuous depth profile make it an ideal system for testing the mechanical properties of a pavement system during any stage of construction. The following simple equation is traditionally used to express the stiffness of a material from DCP test values: PR = Depth of Penetration / Number of Blows If you are new to DCP testing, you may be wondering whether the PR value can be used to calculate to other, more familiar geotechnical parameters, and whether DCP test results correlate well with those from other testing systems. Much has been researched and written on this subject, and the short answer is yes —DCP testing can easily and repeatably measure the same parameters as other in-situ and lab-based soil testing methods. For example, the California Bearing Ratio (CBR) test is another penetration test commonly used to measure the load bearing capacity of road beds. Perhaps you want to know the CBR values for a test site, but you have opted for a DCP system instead, due to its simplicity and lower cost. No problem! PR values can be converted to CBR values by applying a simple equation. This widely used conversion was developed by the U.S. Army Corps of Engineers and is used by many state DOTs and federal agencies: Log (CBR) = 2.465 - 1.12 Log (PR) This calculation and many others can be performed automatically by a state-of-the-art DCP setup. The Vertek SmartDCP kit can be operated and transported by a single user by hand, and provides instantaneous data collection and graphing capabilities via smartphone app. Data can [...]

By smadi66|November 29th, 2019|Geotechnical New Hampshire, Geotechnical New Jersey, Geotechnical New Mexico, Geotechnical New York, Geotechnical Missouri, Geotechnical Minnesota, Geotechnical Mississippi, Geotechnical Nebraska, DCP, Geotechnical Montana, Geotechnical Nevada|0 Comments