CEE students compete at National GeoWall Competition

By Jack Lawrence (BS 23)

On its face, the task of building a miniature retaining wall using only paper seems relatively straightforward. In reality, however, one must evaluate numerous factors including, but not limited to, the strength of the paper, the composition of the backfill material and techniques for soil compaction.

This was the task at hand for the UIUC GeoWall Team which is a subgroup of the Geotechnical Engineering Student Organization (GESO). Before continuing, it is important to mention that geotechnical engineers love to preface just about every word with the prefix “geo” if you give them the opportunity, so you are about to see that prefix a lot. The National GeoWall Competition is one of several competitions hosted within a program known as the GeoChallenges. The GeoChallenges are a series of student competitions held at GeoCongress which is one of the largest conferences for geotechnical engineers within the United States. GeoCongress is organized annually by the American Society of Civil Engineers’ Geo-Institute division.

Every year, the UIUC GeoWall team submits a robust design report to the competition. Each of the designs is then reviewed and approximately 20 institutions are invited to construct their design in-person during the national finals at the conference. The process of creating this year’s design started with performing various geotechnical engineering tests on the backfill material. This year’s competition mandated the use of a highly uniform sand for the backfill material. Luckily, the team received several bags of a similar geological material last year in the form of a very generous donation from a Chicago-based drilling company, so they began testing immediately.

Once testing was complete, it was time to assemble the design itself. The type of retaining wall that the GeoWall competition requires is known as a mechanically-stabilized earth retaining wall. Essentially, this terminology means that several layers of reinforcement strips are installed within the backfill material to maintain the wall’s stability. To optimize the layout of these reinforcement strips, the team created a finite element analysis (FEA) model in a specialized software. This software essentially simulated the behavior of the wall under various loading conditions. The software also allowed the team to reduce the amount of material being used since conservative designs are penalized during the assessment of the design reports.

Following the submittal of reports, the UIUC design was ranked in the top 4 nationally. The exact placement of reports is not released to the teams participating in the competition; however, the competition does release a general range of where your team placed.

Once it was clear that the team would need to travel to GeoCongress 2023, the team worked tirelessly to practice their construction techniques. While it was clear that, in theory, the team’s design would successfully resist all loads applied to the wall, the construction of the wall would need to be of a satisfactory quality so that it could resist these loads in reality. The in-person competition additionally accounted for the time spent constructing the wall, so it was critical to minimize the total construction time in order to score the maximum number of points.

The team also simultaneously commenced fundraising efforts. The goal was to send 16 students to the conference in Los Angeles at an estimated cost of $28,000. After applying for countless grants and writing an immense amount of emails to companies, the team successfully acquired just over $31,000 from seven sponsors and three grant applications.

Eventually, the time came to travel to Los Angeles. In a notable first for the GeoWall team, three team members traveled by car across the United States with all of the equipment necessary to compete while the remaining members flew. When the big day arrived, the competition was intense. The team’s wall flawlessly resisted the static load component of the competition but unfortunately failed during the dynamic loading component. This result unfortunately meant that the team would be disqualified, but this was an important moment for the team as they obtained a substantial amount of data which will be used in the design of next year’s wall.

While the team was disappointed when the wall failed, it did not come as a complete surprise. This year’s design used a factor of safety that was extremely close to 1 which meant that the design was quite risky. It was necessary to use a factor of safety of this magnitude since the highest placing team normally uses a very streamlined design. While the Illinois team could have easily settled for second or third through the use of a more conservative design, they were eager to secure the top placement. After all, the CEE department has a long history of pursuing innovative solutions to the world’s most complex problems and the UIUC GeoWall team could not be more proud of the fact.

The GeoWall team would like to thank their faculty advisor Professor Scott Olson for his invaluable support and technical advice. Companies who are interested in either donating equipment, geological material or sponsorship funds to the UIUC GeoWall team can reach out to uiuc.cee.geso@gmail.com for more information.

Jack Lawrence just earned his bachelor's degree from CEE at Illinois. He was president of GESO during the 2022-2023 academic year.