The National Academies

NCHRP IDEA 20-30/IDEA 221 [Active (IDEA)]

Development of In-Situ Cyclic Borehole Shear Soil Test Device

  Project Data
Funds: $130,000
Staff Responsibility: Inam Jawed
Research Agency: Iowa State University
Principal Investigator: Jeramy Ashlock
Fiscal Year: 2019

This project will develop and test a Cyclic Borehole Shear Test (CBST) device for measuring static and cyclic properties of soils in-situ. The project work will be performed in two stages. Work in Stage 1 of the project will focus on developing the CBST hardware and a software control program and preliminary field testing of the device in Iowa. The electronic and pneumatic components of the CBST device will be specified and procured, the control panels fabricated, and the wiring and pneumatic systems assembled. A software control program will be written using the LabVIEW development environment to control the device and acquire the data. Preliminary tests will be performed in an existing indoor soil pit at the Iowa State University to troubleshoot and assess the device performance. This will be followed by preliminary field tests around Iowa using a truck-mounted Giddings soil probe. Shelby tube samples will be taken using the probe, and laboratory tests will be performed on the samples for comparison with CBST results. Based on the initial field tests, the device and control program will be refined if needed. Additional field tests will then be performed and compared with data from laboratory or other in-situ tests. In Stage 2, field CBSTs will be performed at an Iowa DOT bridge project site and compared with the results of laboratory tests performed by the project team, and possibly in-situ tests performed by others. Additional field tests will be conducted in Virginia in collaboration with a soil testing company that will also perform other in-situ tests for comparison. Finally, field tests will be performed in California to demonstrate the device to Caltrans. The final report will detail all relevant data/information along with guidance on using the CBST device in-situ in the field and plans for its implementation by state DOTs.

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