Digging Deeper – October 2024

Combat Sticky Clays

By Jason Holden

Everyone has heard horror stories associated with clay soils. All you need to do is attempt to dig a hole with a shovel to realize how hard it gets when dry, and feel it stick to your boots like a pair of concrete shoes after it rains. Similar reactions happen to your trenchless equipment while advancing underground. Clay is not an ideal soil type for construction since it is highly reactive to moisture. It is soft and sticky when wet, and hard when dry. If you don’t know much about the soil you are working within, it could spell bad news for your trenchless project.

Identification is Key

It is important to properly identify the ground conditions along the alignment. While it would be wonderful if everyone had a professional to interpret the geotechnical profile prior to the project starting, most seasoned professionals understand that soil investigating is never really done until the project is finished. Fortunately, there are relatively simple ways to determine if your soil is “reactive” or “non-reactive”. If no geotechnical report is available, simply break off a golf ball size clump of damp clay and roll it between your hands. If you can roll it into the thickness of a pencil without crumbling, the ground is going to be reactive and swell. If you can continue to form an even longer spaghetti-like noodle without it crumbling, it will be even more reactive with water.

Industry Solutions

Understanding how a properly designed drilling fluid works with an adequate delivery system for your clay type is very important. Since clay particles can be 1000X smaller than sand, clay particles will have substantially more surface area per volume for water to contact. Certain types of clay molecules have negatively charged locations on their surface that can attract water molecules like a magnet. As additional water is added to clay, the layer of water continues to grow around the clay molecule. This phenomenon causes the clay particles to separate and swell. In some cases, such as mixing Wyoming bentonite for a slurry, this process is a desired result as porosity increases, yet permeability remains low.

There are several discussions about lubrication mixtures within varying soil conditions that are specific to trenchless construction methods such as Akkerman’s Lubrication Tips & Tricks available online. Mud engineers commonly deal with reactive clays by adding clay inhibitors, dispersants, surfactants and clay flocculants.

Akkerman recently released a triplewalled “spinner” pilot tube that was inspired by a Nebraska contractor all-too-familiar with heavy, reactive clay ground conditions in the region. The contractor battled swelling clays and required a solution that would provide more consistent results than using drilling fluids alone.

The design of the triple-wall tube integrates a line-of-sight for the optical guidance system, fluid passage for drilling fluid, and an outer shell that freely rotates as it progresses through the ground. The triple-wall pilot tubes are used in conjunction with Akkerman’s standard pilot tubes. Typically spaced at 50-ft intervals, the triple-wall tubes not only re-form the borehole if swelling has occurred, but they will also serve as a rod stabilizer if the annulus remains supported by the drilling fluid mix. This process subsequently reduces the overall torque and thrust required to install pilot tubes in clay soils leading to less fatigue on auger boring machines.

Recently on a project in Texas, a series of triple-wall pilot tubes were installed on a 375-ft long pilot tube crossing after crews experienced swelling clays on previous installations in the area. Using a drilling fluid recipe that included a PHPA clay inhibitor and wetting agent to reduce the swelling and stickiness of the clay, crews noted an additional 60% reduction in torque after the triple-wall pilot tube were installed.

Triple-wall pilot tubes are currently available. Please don’t hesitate to contact our staff with any questions before the inventory runs out.

35th Akkiversary | Sharon Coordes

AKKiversary Date: October 1989

Current Position: Logistics Coordinator

What did you do before Akkerman?
I was a dishwasher and prep cook at The Old Mill from 1981 to 1984, then I worked at UBC Lumber Yard from 1984 to 1989 when I was hired here.

What most interested you about Akkerman?
I knew absolutely nothing about Akkerman; I didn’t even know they existed back here in the woods. I only knew that I needed a better job, and my brother told me to come here and apply. I was offered a job either in the wash rack or up in purchasing; I said I would take which ever one you feel I would fit best in. Now I am glad it wasn’t the wash rack!

What additional positions have you held with Akkerman?
Back when I first started, many departments were combined. I worked in the purchasing office along with Don Richardson, helping him with busy work and costing. Back then, everything was manual for costing, and it consumed most of my time for many years. From there, I moved over to the main office, where I continued costing until I moved into the logistics end of things. I continued to do the costing, inventory control of the final product, and logistics needs.

What do you like best about your position?
I like the variety of people I get to interact with on a daily basis.

What do you like best about working for Akkerman?
There are so many positive things to say about this company that it is hard to pick one.. I am very fortunate to have been able to work with such a great group of people and to work for a company that truly appreciates every one of their employees. That right there is what sets Akkerman apart from other companies.

What do you like to do in your free time?
Most weekends I go camping through the summer months, and I attend many gun shows in the winter months. I love spending time with my dogs and my friends, and of course, I enjoy my happy hour. Cheers to all of you!

Do you have any interesting memories or funny stories to share?
I had stuffed animals in my window sill and one time several years back, Mark Heimer hung them from my ceiling when I was on vacation. I came back, and all my bears were hanging above my desk. For payback, I bought some Christmas tinsel and cut it into thousands of little pieces. I threw them in the back of Mark’s clown car that he drove, and when he took off, with the windows down, of course, you can imagine what the inside of that car looked like, not to mention what he thought. I would have given anything to see the look on his face.

Additional Comments:
I am very blessed to have been part of this company for so many years. I enjoy coming to work every day because I love the people I work with and the people I work for. I am very proud to tell people where I work that we build such a unique product, and we are a successful family-owned business that I hope continues to be a major player in this industry long after I am gone.

Thank you, Akkerman family, for everything you have done for me and my family for the past 35 years!

Splitting Strings

Every Akkerman machine manufactured in Brownsdale, Minnesota is engineered to be a tool of precision when it comes to trenchless pipe installation. But how precise can we install an underground pipe from point A to B without a line of sight or direct view between the two points? Whether it is an active-laser guided microtunneling system, a passive-laser guided pipe jacking system, or an optical guidance system used in our guided boring machines, our equipment can hit the mark. After working within our engineering team and many change orders/design changes, I got to experience first-hand how the smallest details can create unexpected and unwanted differences in outcome. Before hitting any mark, it all begins with the string line. This seemingly simple tool plays a pivotal role in ensuring the accuracy and efficiency of the trenchless installation process. During my time as an onsite service technician, I have found that the string line positioning methods used by some crews tend to be inconsistent, which can result in a different trajectory than expected.

During the setup stage of many projects, a string line is used for aligning our equipment and guidance systems to a specific azimuth, or bore path, prior to launch. The string line can get in the way when lowering pieces of equipment into the pit, so common practice is to temporarily reposition it out of the way during various parts of the setup. The trajectory will be inaccurate if either end of the string line is not placed back to the original surveyed position. Even if the setup is off by the width of the string, your setup can veer you off course. This can often go unnoticed until the completion of the drive and leaves the contractor trying to decipher if the setup was performed correctly or if the original survey points on the plans were accurate.

What I have found to be a very simple and reliable method for string line placement is to use a hacksaw blade and cut a vertical slot on each of the surveyed positions atop or inside the pit walls. The notches allow the string line to be easily taken down and replaced in the same exact position every time. Moreover, proper alignment reduces the risk of wear and tear on the equipment. When the installation follows the correct path, the stress on the machinery is minimized, leading to a longer operational life and less frequent maintenance. This not only extends the lifespan of the equipment but also reduces downtime, allowing for more efficient project completion.

In conclusion, the string line setup is an indispensable tool in an industry where the equipment can only be as accurate as it is set up to be. By ensuring accurate azimuth alignment, it helps avoid costly mistakes, extends equipment lifespan, and contributes to the overall efficiency of the installation process.

About the Author

Matt recently celebrated his 5^th Anniversary with Akkerman and is currently the Technical Sales Support Engineer. After serving our nation’s military, Matt began his career with Akkerman inside the manufacturing facility where his talents and skillsets were recognized for both jobsite troubleshooting and engineering technical work. Matt has an extensive background with overseas projects including guided boring and sliplining projects in Israel and the United Arab Emirates. He enjoys sharing his knowledge with customers to further develop both on a personal and professional level.