Soil Sampling Attachment Enhances Geotechnical Mobile Lab

Until recently, ISU researchers who wanted to obtain undisturbed soil samples in the field had to take along a soil drilling rig and operator. David White, associate professor of civil, construction, and environmental engineering, had an idea for a more convenient option. Once again, the geotechnical mobile lab staff transformed a basic idea into an innovative solution.

Truck Bumper/Shelby Tube Attachment

Research engineer Bob Steffes and research technician Heath Gieselman designed an attachment for the front of the Freightliner truck that pulls the geotechnical mobile lab. The attachment performs two operations:

• Pushes Shelby tubes vertically into the soil to recover undisturbed soil samples.
• Extrudes the soil sample out of the tube so that soil analysis can be done immediately in the mobile lab.

This new attachment gives the geotechnical mobile lab research team broader control over their soil testing activities with less dependence on outside sources. Soil samples taken with this new device can be analyzed within a few hours inside the mobile lab. This eliminates the need to transport samples to another lab for extrusion from the tube, storage, and later analysis.

Design Challenges

The attachment is mounted on the front end of the truck, replacing the front bumper. Before proceeding with the project, Steffes and Gieselman had to address several questions:

• Was the truck front end reaction weight enough to force a Shelby tube deep into the soil?
• Was it legal and safe to make this modification to the front bumper on this highway truck?
• Would the device exceed the legal width for a truck?
• Could the device be a permanent part of the truck or must it be installed for each use?

White anticipates that this device will be used soon to perform cone penetration tests and plate load tests.

For More Information

The detailed description of the attachment will soon be published as an online tech transfer summary, www.ctre.iastate.edu/research/t2summaries.cfm. In the meantime, contact Bob Steffes, 515-294-7323, steffesr@iastate.edu.