Auger boring is among the critical pieces to the puzzle of infrastructure expansion. As more and more utilities move underground.
“Auger boring is a technique that removes the soil and installs a pipe or casing so you don’t have any road upheaval or soil subsidence,” says McLaughlin president Dave Gasmovic. “Auger boring is ideal for pipe up to 60 in. in diameter and bores up to 600 ft long. “The benefit of auger boring is we are starting from an entry pit and boring to an exit pit — point to point. With HDD you have a lead-in where you have to start to get down to the level you want to be at, and again when you exit; thus, you are installing a lot more pipe and taking a lot more time than needed,” Gasmovic says., the need for equipment that maximizes the available space grows. For sewer and water pipe projects, auger boring is a precise method for installation. Auger boring can be a valuable endeavor for a contractor, but adherence to responsible and accurate operation is crucial.
Even with all the benefits found in auger boring, contractors and operators must first know how to properly operate the machine in order to achieve maxi-mum success. “The very first step is to determine the range of work a contractor will be doing. If they are looking to do work with 54- to 60-in. pipes, then that will require a larger auger boring machine than those looking to work in the 24- to 30-in. range,” Gasmovic says.
When procuring a new auger boring machine, operators should be aware of the intricacies of the machine and be sufficiently trained on best practices. Many manufacturers, including McLaughlin, will visit jobsites and help contractors with their first bore. They discuss safety, machine operation, pit preparation, how to start a bore and how to effectively link the casing. “There are a lot of training aspects and it’s helpful to have an auger boring ex-pert come out and show new operators the machine. It’s helpful to have them explain how to set the machine in the hole and make sure it’s on grade; we also like to stress the importance of having straight-end cut casing that are exact lengths for the bore,” Gasmovic says.
Specifications for the entry and exit pits also need to be adhered to. If the pits are not properly sized, maneuvering equipment and workers may be difficult. Contractors should be aware of the job demands and type of auger machine be-ing used, so they can determine pit size and the proper stabilization methods for greater safety. Road upheaval or subsidence can be caused when using other boring meth-ods that do not maintain accuracy at a deeper subterranean level. This makes auger boring especially alluring when working under paved roads or railroads.
“The challenging part of a crew transitioning to auger boring is learning the setup of the auger machine; it is the most important part of the bore. You need to take more time in preparing and shoring the pit,” Gasmovic says.
The short footprint is another benefit of using auger boring over other trench-less methods. To maximize this advantage, operators should know how to properly prepare and stabilize a pit. The machine needs to be set properly before rotating the auger and the first casing must be installed correctly, or the entire project could fail. When establishing a pit and setting the machine, the operators must take into consideration the use of options including the steering head.
“If you’re using a steering head, the exit pit has to be large enough to take that head off. If the exit pit is deep, it needs to be properly shored and stabilized so workers can go down there, take the cutting head off before removing the auger,” adds Gasmovic.
Auger boring is not only a suitable method for working around roadways and railroads, as previously mentioned, but the actual process for installing an auger bore machine can be compared to laying railroad tracks. “Basically setting up an auger boring machine is like setting up a railroad. You have a track that goes down in the hole first. Then you have your power unit, which will consist of an engine, gear box and a transmission, and lastly the means to move the machine forward on the track, which is hydraulic cylinders,” Gasmovic says.
Technology is advancing the auger boring industry, primarily in terms of targeting and maintaining accuracy. The On-Target system is one way that McLaughlin has found to increase grade integrity while boring. “With the On-Target system, we use two halogen lights and a simple plumb bob setup to watch if the casing is moving left or right of our target line, hydraulic flaps force the casing to stay on its target line,” Gasmovic says. “Before the On-Target system, we could tell where we were going to come out on grade, but line was a little suspect. Now we can tell them where we’re going to come out, on line and on grade.”
Gasmovic still advocates using the classic water line method for further maintaining grade on bores. “We still use a water level, which is the most effective way to manage grade, to read grade, to read the elevation of the bore,” he says.
In these demanding workspaces, auger boring is becoming a more in-demand option. For contractors looking to achieve minimally invasive bores and get the job done more efficiently, the auger boring method is suited to accomplish these demands.
This article originally appeared in the December 2013 issue of Trenchless Technology. For more information, please visit www.trenchlessonline.com