Mud Rotary Drilling and Cone Penetration Testing (CPT) both provide reliable options for gaining subsurface information. In fact, the two are even compatible – many organizations that order drilling services, such as mud rotary drilling are also using CPT for their operations. Mud Rotary Drilling Mud rotary drilling is a versatile and dependable method for geological drilling operations. It is most commonly used to create a hole that will then be used for water well, seismic testing and commercial drilling operations. The mud rotary drilling functions with a drill-bit that is attached to a drill-rod that rotates into a borehole. This is done while pumping a drill mud that contains bentonite or polymer slurry into the borehole. Once this operation is complete, the drilling mud will circulate into a mud pit where the remaining residue in the borehole caused by drilling will then come out and be reused. This process is done without any effort from the drilling operators, and speeds up the drilling by removing any potential obstacles. Cone Penetration Testing (CPT) Cone Penetration Testing (CPT) is the use of a hardened cone shape that is pushed into the ground to substantial depths. The cone is pushed using steel rods that are able to be connected to each other as the depth increases. A dominant hydraulic ram is used to produce a considerable amount of downward force to facilitate the cone to penetrate soft soils, sand and clay. Though both provide suitable options for obtaining subsurface information, there are many benefits to using CPT over drilling. First off, CPT is a faster, less expensive option that also provides immediate results on site. CPT can also point to where rotary mud drilling will be required which is typically because of subsurface conditions or where more sampling should be done. CPT [...]
Geo-technical tests are performed by geo-technical engineers, geo-technical technicians or engineering geologists to understand the characteristics such as the physical properties that exist underneath a work site. Geo-technical testing will include a walk around of the surface conditions as well as one or more of a variety of tests. Tests generally fall into 4 categories, test pits, trenching, boring and in-situ testing. Test Pits Test pits are much like you would expect, a pit is dug either manually or with an excavator in order to reveal the sub-surface conditions to the depth desired. Trenching Trenching is similar to Test pits except that in this case, the pit is elongated over some distance in order to establish how the sub-surface conditions change over various parts of the work site. A range of soil samplers can be used to extract test samples including shovels, hand-driven augers, split-spoon samplers, modified California samplers and Shelby tube samplers. Boring Borings, usually small-diameter borings, provide the opportunity to physically remove soil or rock samples for testing. Borings provide the advantage of letting you ‘see’ the actual materials, but for certain types of soils, the very act of boring can disturb the soil conditions and the samples extracted may not represent what the conditions will actually be for building and supporting structures since it is unscientific and void of actionable data. Generally, soil samples from the above tests are taken to a lab where they are evaluated. In-Situ Testing In-situ (in the situation, or at site) testing methods include penetration tests such as Standard Penetration Tests (SPT), which penetrate via drilling, and various Cone Penetration Tests, which penetrate via direct push . These tests measure the physical properties of the subsurface soil directly, without removal. This provides the advantages of generating a more accurate reflection of conditions [...]
A widely used soil testing procedure is the Standard Penetration Test (SPT). This test is still used because of it's simplicity and low cost. It can provide useful information in very specific types of soil conditions, but is not as accurate as a Cone Penetration Test. Here's more information about this basic soil testing procedure. For this test, a sample tube, which is thick walled to endure the test environment is placed at the bottom of a borehole. A heavy slide hammer (140 lbs) is dropped repeatedly 30 inches onto the top of the sample tube, driving it into the soil being tested. The operation entails the operator counting the number of hammer strikes it takes to drive the sample tube 6 inches at a time. Each test drives the sample tube up to 18 inches deep. It is then extracted and if desired a sample of the soil is pulled from the tube. The borehole is drilled deeper and the test is repeated. Often soil recovery is poor and counting errors per interval may occur. The number of hammer strikes it takes for the tube to penetrate the second and third 6 inch depth is called the 'standard penetration resistance', or otherwise called the 'N-value'. The standard penetration resistance offers a gauge of the soil density of soils which are hard to pull up with simply a borehole sampling approach. You can imagine pushing a sample tube into gravel, sand or silt and struggling to recover samples that are useful for analysis. Coupling the standard penetration test with borehole drilling and sampling can be an improvement for understanding certain soil types underground. This basic soil testing procedure gives reasonably consistent results in fine-grained sands and is not as consistent in coarse sands or clays. It can be useful in [...]
At Vertek CPT we love to develop innovative, yet practical CPT solutions with real ROI. There are many situations where an ultra-mobile, yet reliable CPT push system makes a lot of sense. In areas where it is difficult to get rig-based CPT equipment into place, maybe due to the terrain, soil conditions or distance from the nearest road, a CPT system that can be carried and operated by a small crew makes sense. Maximize Your Soil Testing Service Vertek's 10 Ton Portable Cone Penetrometer Test (CPT) hydraulic load frame is the lightest, smallest, most portable hydraulic CPT unit available. The hydraulic power pack and the hydraulic cylinders are independent and coupled by hydraulic quick-disconnects. The aluminum twin cylinders and power pack weigh only 195 kg (430 lbs) and 160 kg (355 lbs) respectively. Even within this lightweight form-factor, the unit still pushes up to 10 tons, meaning that you can reach the depths necessary for many types of tests. After setting 4 sturdy augers with the included drive unit and hand tools as simple as a tape measure, you are ready to mount the unit and start pushing. You can see how easy transportation, set-up, operation and tear-down are here: [/fusion_youtube]
Japanese CPT Services Built by Vertek Land Concierge Inc.’s subsurface technology manager Hideyuki Sato and colleague Yoshihiro Imai visited Vertek CPT's manufacturing facility for a demonstration of our S4 Cone Penetrometer Test (CPT) push system and Data Acquisition Systems (DAS). Land Concierge Inc. has been a customer of Vertek since 2009 and is our sales agent in Japan. Contact Mr. Sato with your Japanese soil testing equipment needs and questions. Vertek personnel demonstrated the versatility of the S4 and provided an interactive tour of our CPT fabrication facilities. Mr. Sato indicated that requests for CPT testing in Japan has increased since 2011 and many of his customers that are interested in incorporating Verteks’ S4 and CPT equipment into their business. Land Concierge's clients focus on: Contaminted sites Site characterization Bio-remediation Geothechnical in-situ testing Soil and groundwater sampling If your organization would like to send a representative to our Vermont facility to learn more about the CPT business and technologies, contact us today.
In-situ soil testing is essential for gaining soil property information, measuring groundwater pressure, gathering moisture content data and other important data points, all in which can be safety-critical in a number of different instances. In today's post we are going to take a deep dive into a few different types of soil tests that can be performed in-situ. In-situ soil testing can be accomplished in a variety of different ways. Every soil test has its own place and benefit; however, the most accurate and thorough in-situ soil testing for determining a wide variety of technical attributes is Cone Penetration Testing (CPT). Just like everything else, determining what is best for your business is more efficient and effective once you have determined the pros and cons for every possible solution; in this case a testing solution. Options for In-Situ Soil Testing Procedures Here is a closer look at a few different options for performing an in-situ soil test: Standard Penetration Testing (SPT): This option is dynamic, low in cost and has been widely recognized as a simplified solution that provides useful information. While it's reasonably consistent with it's results in fine-grained sands it's not as consistent with coarse sands or clays; which can be difficult for gathering accurate data and analysis of soil conditions. For even more on Standard Penetration Testing, visit one of our previous posts that takes a closer look at SPT for your business. Dynamic Cone Penetrometer (DCP): A DCP manually lifts it's weight and drops into a cone that will then penetrate into the ground. It will record the number of mm per hit as well as gather an estimate of different soil properties, however it doesn't have as many capabilities as the CPT, and can only estimate certain properties. Cone Penetration Testing (CPT): This option collects [...]
As we've noted in other posts, CPT provides a number of benefits over traditional methods of subsurface soil characterization. These benefits include: Traceability Reports from a specific sounding are easily traced back to the source data, and because CPT is a continuous process, data points in between those reported can be evaluated post-test. This is in contrast to geotechnical boring where individual samples need to be tracked and accounted for from the busy worksite to a remote lab and through to reports and documentation. This can be cumbersome and prone to errors. Immediacy Reports can be generated in near-real-time. This enables customers such as site owners or civil engineers to have visibility to the tests as they are occuring. Having immediacy means that as data is reported and interpreted, any retesting that should be done or any additional soundings that would be useful to clarify or validate data can be called for on the spot. Accuracy Because of the very large volume of soundings that have been done, important factors and relationships have been established that enable the raw CPT data to be translated into useful information. Additionally, as we've noted elsewhere, CPT leaves the soil being tested 'undisturbed' and therefore provides a more accurate assessment than other methods of soil characterization. CPT Data analysis and interpretation can be aided through the use of specialized software Two that our customers have had success with include DataForensics & Datagel. Using software to log, analyze and report your data provides a number of advantages. Traceability, immediacy and accuracy are improved. Additionally, efficiency and therefore your cost structure, benefit as well. With the right software you are able to accelerate your ability to serve customers both more quickly and more accurately. If you are entering or have recently started out in the CPT [...]
In the construction of high load structures such as dams, paved roadways and construction projects that rely on the stability of embankments; soil compaction is used to increase soil strength. Loose soil can be compacted by using mechanical equipment to remove air-voids, thereby densifying the soil and increasing it's dry unit weight. There are a variety of different benefits to soil compaction, including: prevention of soil settlement and frost damage, increased ground stability, reduced hydraulic conductivity and mitigating undesirable settlement of structures, such as paved roads, foundations and piping. Below you will find a few different examples of how a soil compaction test can be performed. Standard Proctor Compaction Test: Standard Proctor Compaction Testing can be performed in a lab. The testing first determines the maximum density achievable for the soil and uses it as a reference for field testing. It also is effective for testing the effects of moisture on the soil's density. For soil with higher densities a Modified Proctor Compaction Test which uses higher values will be necessary. Materials Needed: 1/30 cubic ft. mold 5.5 lb. hammer 12" drop 3 layers of soil 25 blows Obtain layered soil sample (via our VTK Soil Sampler if equipped) Determine the weight of the Proctor mold with the base and the collar extension Assemble the compaction tool Place soil in the mold in 3 layers Compact the soil with 25 well distributed blows of the hammer Carefully detach the collar extension and base without distributing the soil Determine the weight of the Proctor mold and the soil Oven dry the soil for 12 hours to determine the moisture content Compaction energy can be calculated with this test by using this formula: ((#blows) x (#layers of soil) x (weight of hammer) x (height drop)) / mold volume Field Tests: Field Tests [...]
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]
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!