Whether you are just learning about geotechnical engineering and its related fields or you are a veteran looking at current materials, these resources outline the basics. Geotechnical engineering focuses on the soil beneath our feet. The structural properties of the ground can affect what types of buildings can be built. Additionally, geotechnical engineers can conduct tests on soil and concrete properties. Covered in this section are a variety of articles about Cone Penetration Tests, drilling, different types of augers and more.

Adding a Soil Testing Service to Your Drilling Business

Are you a driller looking at adding a soil testing service to your business? If you’ve been in the drilling business for any length of time, or if you’ve been involved in drilling around sites that are being prepped for construction or development - you may have crossed paths with a Cone Penetration Test (CPT) operation. If you have been curious about this service, you probably noticed that the operating conditions of CPT are pretty comfortable. You may have also heard that the daily rates or rates charged per foot of depth for CPT are usually quite a bit better than what you can get for drilling. Adding soil testing services to your business can be a good way to diversify your workload and ensure a steady income for your business and your family. What you may not know, is that the skills you’ve acquired to drill are a good basis for entering the CPT business. What do you need to get started? A good place to start is to start comprehending the reasons why customers need a soil testing service and the basics of how this type of soil testing works. This will help you to start thinking about the needs in your area and the types of things you’ll need to learn in order to be successful in the business. Why a Soil Testing Service? When engineers are in the early stages of designing infrastructure, such as roads, bridges, or foundations for buildings, they need to know the characteristics of the ground that is going to be built on. Depending upon the type of construction, they may need to understand how soil, clay and rock are layered below the surface. This can help them to decide what the construction process will look like. For instance, will blasting or [...]

MUD ROTARY DRILLING VS. CPT

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 [...]

What is a Cone Test? If you want to know the basics, start here

A Cone Penetration Test (CPT) also referred to more informally as a Cone Test, is a way to get at subsurface information without having to directly sample the subsurface. Many organizations that order drilling services are also using CPT within their operations. CPT testing services is a good support option to well drilling services, since many of the potential customers and skills overlap. What is Cone Penetration Testing? Cone Penetration Testing (CPT) is the practice of using an ASTM standard hardened cone shape that is directly pushed into the ground to substantial depths. The cone is pushed using steel rods that are able to be connected to each other in 1 meter lengths as the depth increases. A powerful hydraulic ram is used to generate a substantial amount of downward force to enable the cone to penetrate soils, sand, clay and sometimes even soft rock. In order to keep the surface equipment (truck) in place and not simply be lifted up by the ram force, the vehicles that the CPT equipment is mounted on or in are typically quite heavy. Also, the use of anchor systems to the ground will increase the ability of any vehicle mounted CPT system to push harder and therefore deeper. There are a couple of different imperative goals to any subsurface investigation. The first one is the nature and sequence of strata or soil,sediments and other geological subsurface features. Using CPT for this is called geo-technical testing. In addition, the groundwater conditions can be established during a sounding. CPT can be used to determine: the composition, strength and distribution of subsurface soils. These can range from clay, sand, bedrock, groundwater table, hydrocarbons, contaminants and more. Advantages of CPT There are many different advantages to Cone Penetration Testing (CPT), including, prompt collection and interpretation of field [...]

Why Would You Need a Track CPT Rig?

Vertek CPT wants to ensure that you have the right equipment to grow your business. As you are going through the CPT rig purchase process, we’ll have extensive conversations to ensure that we are both on the same page when it comes to where you will be testing, what types of tests you can most easily sell, and which rig or rigs will help you to make the most money. Track Rig Features As you look around our site, you’ll see that some rigs are built on tracks, as opposed to truck beds with wheels. As per with construction equipment, you might expect the tracked equipment to be larger, with CPT rigs the tracked units tend to be smaller. This is because tracked rig CPT platforms are designed to not only traverse and work in difficult terrains, but also to be highly maneuverable around obstacles such as trees, rocks and gulleys. Remember, CPT testing may be specified by your customer for pre-construction activities, meaning that it takes place on a site with little preparation. Having a highly maneuverable platform with low ground pressure can make the difference between you being able to win certain jobs and not. Track rigs are usually designed in order to distribute the weight of the rig over more square inches of contact area. This helps to minimize damage to sensitive areas as well as help the rig not get stuck in less than optimum ground conditions. The overall rig footprints are designed so that the units can be effectively trucked to sites within your service area. Track rigs are designed for deep pushes in tough geologies and the Vertek CPT tracked rigs push from about 10 tons up to 25 tons. With the right combination of weight, ease of maneuverability and set-up features, a tracked [...]

Presenting CPT Data to Owners & Engineers: an Important Role of CPT

If you are considering entering the CPT business from, let’s say, operating a well-drilling business, you’ll want to prepare yourself for a few adjustments. Depending upon the type of business you are used to running or being a part of, you’ll find that the customer interactions may be different. CPT testing is all about gathering data from field tests and quickly turning that into useful information for the site owner, an engineer, construction company, government agency etc. This blog is an introduction to the basics of CPT reporting. We’ll start with what we’re trying to measure, then we’ll discuss how a CPT system, and in particular the probe, gathers specific types of useful data. Then we’ll, look at some ways that this data is interpreted to make useful information for your customer to make decisions. In real life, you’ll want to use a software application that quickly and efficiently does this interpretation for you. However, Vertek CPT believes in training it’s customer partners from the ground up (so to speak) so that you are comfortable and confident in every conversation you’ll have. What are we trying to measure? CPT is the quickest and most cost-effective way to map out what the soil conditions are under your feet. If you imagine being able to look at the ground ‘from the side’, you’d see layers something like this: For people responsible for building highways through hilly territory, or building a heavy structure, it’s important to know what’s underground before they begin planning. This is where CPT comes in. CPT lets you draw a picture of what’s underground for folks who need it. How Does a CPT Probe Gather Useful Types of Data? So let’s start with the Cone, the ‘C’ in CPT. If you look at the picture below, you can imagine [...]

Hollow Stem Augers Don’t Provide the Accuracy that CPT has to Offer

Geo-technical Boring is less accurate, less efficient and more expensive than Cone Penetration Testing (CPT), here's why. When it comes to selecting a method for subsurface investigation and testing you are presented with different options. From the Standard Penetration Test (SPT), which is a type of Geo-technical Soil Boring to Cone Penetration Testing (CPT) there are many options to consider, and each provides certain advantages over the other. Today we’re going to compare Geo-technical Boring to CPT. Geo-technical boring is a method of drilling which is performed for site investigation. This drilling technique is most commonly used to obtain information on the physical properties of soil and rock under a foundation. This information helps to determine the depth of the foundation, ensure the site is safe and determines if structural compensations will be needed. This also ensures that the foundation, caissons and various supports are built in the right place. Hollow Stem Augers One type of geo-technical boring using a hollow stem auger is the Standard Penetration Test. Like it's name suggests, a hollow stem auger is a drilling tool that enables you to capture soil samples in the hollow portion of the drill for retrieving to the surface. One advantage of this approach is that you have actual soil samples you are working with. In the case of identifying the presence, location and depth of specific types of contaminants, this can be useful. Cone Penetration Testing Though geo-technical boring seems like a sufficient option for site subsurface investigation, geo-technical boring doesn’t provide the accuracy and efficiency that Cone Penetration Testing (CPT) can offer. Geo-technical Boring has the advantage that it uses many of the skills of conventional well drilling. Because the Boring operations and technical analysis, such as laboratory tests, are separate, Geo-technical Boring can require less skilled operators [...]

4 Types of Geotechnical Testing: What is the Best Option for You?

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 [...]

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. Cone Penetration Testing 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. Deciding Between CPT Rigs 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 Importance of Proper Soil Quality

Sometimes it's hard to imagine how important designing the proper foundation support for a structure can be. The public may assume that the ground we are standing on is pretty much stable and should be able to hold whatever we build on it, without consideration of soil quality. However, there are examples throughout history of structures that were built upon soil conditions that were not suitable for their weight. Perhaps the most famous is the Leaning Tower of Pisa. With better soil quality, it may have been known today as the Tower of Pisa Unfortunately for the constructors, the Tower was built upon a patch of soil that was too soft on one side for the pressure the structure would exert as it's height climbed. The Tower actually had begun leaning during the construction process and had quite a tilt before it was even completed. Over time, builders began to realize that in order to build magnificent structures, and to have them endure over time, they had to understand the geology they were building on. They had to be able to translate an understanding of the soil quality that is not able to be seen into foundation designs that would support even the tallest skyscrapers we build today. Through lots of experimentation, science, engineering and creative solutions, we've been able to evolve our understanding of how to perform a variety of soil tests and how to link that to solid design and construction methods that will support structures as varied as highway bridges and high-rise buildings. As you explore the resources that we've provided in our CPT University, you'll learn about a variety of soil tests and the advantages of each. Tests such as Standard Penetration Tests (SPT), Cone Penetration Tests (CPT) and other forms of testing all have their [...]

Standard Penetration Test (SPT) a Basic Soil Testing Procedure

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 [...]

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