Auger Drilling Method
Vennie Fireman
Auger drilling is a drilling method primarily used for soil sampling and ground exploration. In essence, it's a technique that has helped environmental firms, civil engineers, and construction firms for years. This blog post is a comprehensive guide to auger drilling, its advantages, and where it's commonly applied.
At its core, auger drilling is a process wherein a helical screw (or auger) is driven into the ground. As the auger rotates and delves into the soil, it brings the excavated materials to the surface. This process ensures that the borehole remains open and free from collapse. The spiral design of the auger blades helps in this excavation process.
Hollow stem auger drilling: This method uses a hollow, cylindrical stem and auger flights. Once the desired depth is reached, samples can be extracted through the hollow stem without having to remove the auger from the ground.
Geotechnical exploration: Before commencing a construction project, it's vital to understand the soil's properties. Auger drilling provides insights into soil composition, strength, and other critical factors.
Auger drilling is a vital tool in the world of ground exploration and construction. Its versatility, efficiency, and cost-effectiveness make it a preferred choice for many professionals in the field. Whether you're a seasoned geotechnical engineer or a curious individual, understanding this method's intricacies can be both fascinating and beneficial.
The bucket auger is used primarily on unconsolidated material, for constructing large-diameter boreholes ranging from 24 inches to 48 inches. These large-diameter boreholes are ideally suited for areas producing low-yielding wells in aquitards.
The drilling system consists of a truck-mounted drill with a separate deck-mounted engine, which must be capable of generating enough torque to overcome the friction associated with drilling such a large-diameter hole.
The cutting action is rotary cut. The bucket is rotated and advanced until it is full of cuttings, at which time it is tripped out of the hole, swung to one side, and a trip is released, emptying the cuttings onto the adjacent ground. Note that no flushing media is used, since the bucket auger removes the cuttings as hole penetration occurs. This produces cuttings which are clean, unmasked, and representative of the geology.
This drill utilizes a large-diameter table drive to rotate the telescoping kelly, which in turn advances the bucket auger. Penetration rates are generally quite rapid in favorable conditions. During the drilling process, the hole may require the installation of temporary or working casing to stabilize the hole until permanent casing is installed. Drilling continues through the working casing, using a smaller bucket until such time as an adequate aquifer is located. The four telescoping sections of the kelly bar enable the bucket auger to drill up to 100 feet in depth, without the use of additional kelly bar sections.
The next step in this process is the installation of the permanent casing, which can be manufactured from concrete, galvanized steel, or fiberglass. Shown here is the installation of concrete casing using a tile center. The annular space between the casing and the borehole wall at the aquifer area is filled with permeable material, such as gravel or washed stone. The well is grouted and developed to a sand-free state, as per Regulation 903.
Auger drilling is a method for installing auger piles and is usually done for drilling in minor depths through loose rock. Installing the piles via auger drilling helps in balancing the load of a construction in deeper soil layers. Auger drilling is largely free from vibration and noise, which is why the technique can also be used in urban areas. This is one advantage drilling augers have over methods such as drive drilling.
One of those is continuous flight augering (CFA). This is considered the standard auger drilling procedure as described above. We offer cutting edges, customized for the respective geology of the building site. Furthermore, we adjust the size and length of the drilling augers for your specific building project.
Drilling augers by EMDE are made in Germany, high-quality and robust. Thanks to thorough consulting we guarantee that you receive the perfect device and configuration for your individual construction project.
Geotechnical drilling is a fundamental part of any construction site evaluation. Drilling deep into the ground helps reveal the conditions below, allowing engineers and architects insight into what kind of environmental hazards need to be accounted for. Some of the most commonly used geotechnical drilling techniques include mud rotary drilling, hollow stem auger drilling, and solid stem auger drilling, and depending on the site, you may need to use one or more techniques.
Mud rotary drilling is a frequently used geotechnical drilling technique that is favored for its speed and adaptability. This method lubricates the drill bit with pumped drilling fluid (typically water combined with various fluid enhancers such as bentonite), which allows the drill bit to stay cool while in operation. It also pressurizes the bore hole to help keep the walls of the boring in place, minimizing caving.
Mud rotary drilling does have a few drawbacks though, particularly around the necessary drilling fluid. In order to pump in the fluid, support vehicles must accompany the rig, which can disturb the investigation area and compromise sampling findings. This technique is also not advised for conditions where environmental wells are needed.
Complications with hollow stem auger drilling arise during use with unlithified sediments or when drilling is needed beyond 100 feet deep. This geotechnical drilling technique does not work well with shallow bedrock or other challenging subsurface materials.
Solid stem auger drilling excavates and transports samples and cuttings to the surface for future study. Using continuous flight augers in a range of diameters, this method produces reliable results with smaller-sized rigs than other techniques.
In order to complete your geotechnical report, you may need to implement geotechnical drilling around your project site. This vital service is provided by Central Geotechnical Services, your partners in project feasibility. For questions, contact us today.
First used in 1936, horizontal auger boring, also known as jack and bore, is one of the most common trenchless technology methods. This method excavates boreholes beneath the surface and allows contractors to install new pipes while minimizing above-ground impact. Read more to learn about the pros and cons of horizontal auger boring and why it is a staple in the trenchless technology sector.
HAB is an established, tried-and-true method within the field of trenchless technology. Due to its commonality and familiarity with contractors, it has become one of the most inexpensive and low-tech trenchless methods.
The typical pipe lengths for HAB can be anywhere from 20 feet to 500 feet, and the diameter anywhere from eight to 100 inches. HAB also utilizes steel casing pipes to encase the carrier pipe. For example, an eight-inch pipe will have a 16-inch steel casing pipe. The auger bore installs the steel casing pipe first, and then the eight-inch carrier pipe is pushed through with casing spacers.
HAB may be the best solution to minimize environmental impacts. For example, an owner must procure a 404 permit before crossing a wetland. HAB may allow owners to bypass securing the permit since the boring occurs under the area, not through.
Additionally, no drilling fluids are needed to execute HAB. This is especially ideal when working near railroads or protected wildlife areas, which do not allow fluids for boring or construction due to concerns about fracking and water seepage.
However, there are ways to ensure the bore stays on track. One method is to pull the auger out after a few feet and then use a laser level to survey if the bore is on the right path. This method can take time, so many contractors may choose to forgo it and proceed with other instruments, such as a water leveler. To mitigate the risks of the bore running off track, contractors can drill a small pilot hole through the desired pipe installation path and then guide the auger along the established path. Like the laser level process, the pilot hole method is time-consuming, but it is also one of the most reliable and accurate methods.
Tyler has more than 13 years of experience as a project manager, project engineer, and discipline task leader on water and wastewater infrastructure and rehabilitation projects. His experience includes planning, design, and construction phase services for water, sewer, and reclaimed water projects across the western half of the US. His trenchless design experience is diverse, including horizontal auger boring, horizontal directional drilling, hand tunneling, micro tunneling, pipe bursting, slip lining, and cured-in-place-pipe.
Marty is a Trenchless Technology Practice Leader with more than 30 years of experience in the design of water and wastewater infrastructure and rehabilitation projects. He has worked on over 200 miles of large- and small-diameter water and wastewater pipeline projects, ranging from six-inches to 120-inches and has assisted multiple municipalities with planning, design, and construction phases. He has experience resolving a variety of project challenges ranging from the operations level to the administrative level. His experience includes 200,000 linear feet of trenchless replacement/rehabilitation methods, including cured-in-place, pipe bursting, horizontal directional drilling, microtunneling, fold and form, slip lining, tunneling, and horizontal auger boring.
When constructing bridges, tunnels, skyscrapers and other structures that reach deep into the ground, drilling methods play an important role. There are multiple methods for constructing piles as stable and secure foundation elements for a structure. The most common drilling methods include Kelly drilling, cased or uncased continuous flight auger drilling and full displacement pile drilling.
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