Development of In-Situ Cyclic Borehole Shear Soil Test Device

In this project, a Cyclic Borehole Shear Test (CBST) device was developed to enable rapid in situ measurement of cyclic behavior and monotonic shear strength properties of the soil. The CBST is unique in its ability to measure the parameters in the soil’s natural setting, under cyclic loading, and in a matter of minutes whereas present laboratory techniques can take several weeks. By testing the soil in situ, the device saves time and money, while reducing effects of soil sample disturbance which can significantly affect laboratory test results. Based on the results of several field testing trials, numerous refinements and modifications were made to the system that included the physical testing apparatus inserted into the borehole, the electronic and pneumatic measurement and control system, and the software control program. Comparisons of the field CBST results to those of conventional laboratory cyclic direct simple shear tests demonstrated that the device can measure meaningful cyclic behavior of soils in situ. Further research will be pursued to more rigorously relate the measured displacements to shear strains in the soil surrounding the borehole, and to explore applications of the device to in situ measurement of the liquefaction behavior of soils. With further research, the device has the potential to fundamentally transform the presently empirical techniques used in practice for assessment of soil liquefaction resistance into a more mechanistic physics-based framework. The final report is available.

• Record URL:
  http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=4900

Language

• English

Project

• Status: Completed
• Funding: $130000
• Contract Numbers:

  Project 20-30, IDEA 221

• Sponsor Organizations:

  National Cooperative Highway Research Program

  Transportation Research Board
  500 Fifth Street, NW
  Washington, DC  United States  20001

  American Association of State Highway and Transportation Officials (AASHTO)

  444 North Capitol Street, NW
  Washington, DC  United States  20001

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Project Managers:

  Jawed, Inam

• Performing Organizations:

  Iowa State University

  ,    
• Principal Investigators:

  Ashlock, Jeramy

• Start Date: 20230320
• Expected Completion Date: 0
• Actual Completion Date: 20230320

Subject/Index Terms

• TRT Terms: Boreholes; Field tests; Laboratory tests; Shear tests; Software; Soil tests; Test procedures; Testing equipment
• Geographic Terms: California; Iowa; Virginia
• Subject Areas: Geotechnology; Transportation (General);

Filing Info

• Accession Number: 01721964
• Record Type: Research project
• Source Agency: Transportation Research Board
• Contract Numbers: Project 20-30, IDEA 221
• Files: TRB, RIP
• Created Date: Nov 4 2019 9:02PM