A Modern Geophysical Approach to Mapping Clay In The Subgrade—Case Study

The presence of clay beneath roadways poses a significant problem to road rehabilitation design and construction. Conducting precise subgrade soil investigations to determine the location of potential clay-rich zones rapidly and nonintrusively is of great interest to the -geotechnical engineer. A multi-phase program was designed to demonstrate the effectiveness of the Electromagnetic Induction (EMI) method as a state-of-practice geophysical imaging tool for mapping the presence of clay seams in the subgrade beneath roadways. The objective of this study is to compare the results from traditional subsurface soil investigation to a nonintrusive investigation using the EMI method. The results indicated that the EMI is a promising geophysical tool to enhance the traditional geotechnical engineering investigations. It is a fast, efficient, and cost effective tool for mapping volumetric variations in soil conductivity beneath roadways. A strong correlation between soil conductivity and the Atterburg Limits of soils was not established; however, a qualitative evaluation of areas with increased potential for high plasticity clay content can be estimated from the EMI data. The EMI tool can be used to focus the soil boring programs during project site investigations, road rehabilitation, and construction.

• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Pfeiffer, Jim
  • Hanna, Kanaan
  • Arslan, Haydar
  • Haramy, Khamis Y
  • Mohammed, Khalid
  • Surdahl, Roger W
• Conference:
  • Transportation Research Board 87th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2008-1-13 to 2008-1-17
• Date: 2008

Language

• English

Media Info

• Media Type: DVD
• Features: Figures; Photos; References;
• Pagination: 14p
• Monograph Title: TRB 87th Annual Meeting Compendium of Papers DVD

Subject/Index Terms

• TRT Terms: Clay soils; Cost effectiveness; Electromagnetic induction; Evaluation and assessment; Geophysical prospecting; Geotechnical engineering; Highway design; Permeability; Rehabilitation; Road construction; Soil mapping; Soil mechanics; Subgrade (Pavements)
• Uncontrolled Terms: Site investigation
• Subject Areas: Geotechnology; Highways; I42: Soil Mechanics;

Filing Info

• Accession Number: 01089219
• Record Type: Publication
• Report/Paper Numbers: 08-2660
• Files: TRIS, TRB
• Created Date: Feb 27 2008 8:58AM