Enhancing the Reliability of Transportation Structures by Quantifying Strength Reduction Magnitude of Soils in Midwestern States

For highway structures in Nebraska and many Mid-Western states, the extreme precipitation brought the failure of slopes even though they were designed and constructed complying with relevant codes and practices. Back analyses of these failed slopes showed that the strength of soils at failure turned out to be substantially lower than the tested one at the design stage. Further studies showed that this kind of substantial strength reduction was due to the strength reduction of glacial tills during wet seasons. This reduced strength of soils is called “Wet-Drained-Fully-Softened-Strength (WDFSS)”, however, the method to evaluate this critical strength takes extremely long time (months if not years for one test) and high cost. This research team developed a new field-testing method to evaluate this critical strength by utilizing an innovative “self-wetting” CPT-based method that can evaluate this WDFSS in a rational time span, that is usually a day. This research team, therefore, proposes to evaluate the WDFSS of various Nebraska soils with this innovative CPT method, so that WDFSS can be conveniently obtained and utilized for design work. In addition, this study includes the Santee Reservation area – one of Native American Reservations in Nebraska as one of test sites. This area showed as high as 90% strength reduction for clayey glacial tills in the previous study (Song et al. 2019). Providing specific geotechnical information to the tribal government will greatly enhance the usage of their territory in more resilient and productive ways.

Language

• English

Project

• Status: Active
• Funding: $152,504.46
• Contract Numbers:

  69A3552348307

• Sponsor Organizations:

  Office of the Assistant Secretary for Research and Technology

  University Transportation Centers Program
  Department of Transportation
  Washington, DC  United States  20590
• Managing Organizations:

  Mid-America Transportation Center

  University of Nebraska-Lincoln
  2200 Vine Street, PO Box 830851
  Lincoln, NE  United States  68583-0851
• Performing Organizations:

  University of Missouri, St. Louis

  1 University Boulevard
  St. Louis, MO  United States  63121-4400
• Start Date: 20241115
• Expected Completion Date: 20260630
• Actual Completion Date: 0
• USDOT Program: University Transportation Centers Program

Subject/Index Terms

• TRT Terms: Aggregates; Erosion control; Road construction; Road materials; Soil stabilization
• Subject Areas: Design; Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 01971870
• Record Type: Research project
• Source Agency: Mid-America Transportation Center
• Contract Numbers: 69A3552348307
• Files: UTC, RIP
• Created Date: Nov 20 2025 4:18PM