Project Report

My time at Chuo University this summer was spent predominantly on two projects: Research project 1: Analyzed large amounts of KiK-net site amplification data from the March 2011 Tohoku Earthquake. KiK-net is the name given to an extensive strong-motion seismograph network that was installed in Japan after the 1995 Kobe earthquake. It is the densest seismograph network of its type in the world. KiK-net is unique because each seismograph location has one instrument at the ground surface, and another "downhole" instrument that is installed in a borehole. The downhole instruments are located at the interface between bedrock and soil. By comparing the frequency content of the recorded motions at the two locations at each site, details of seismic wave amplification near the earth’s surface can be inferred. Site amplification is of great interest to earthquake geotechnical engineers and strong-motion seismologists, as it plays a major role in determining the nature of earthquake motion at the ground surface, and the extent to which they will be damaging to infrastructure when earthquakes occur. The intellectual merit of study of site amplification ratios is the potential for advancement of understanding of amplification effects during dangerous earthquakes. The broader impacts of the study this summer included assisting a Japanese researcher in the laboratory with compiling this data; regular interaction with other Japanese researchers and the associated cultural and educational exchanges. Research project 2: Tested liquefaction susceptibility characteristics of soils using the Kokusho Mini-Cone Triaxial Device. Liquefaction is a phenomenon that can occur in loose sandy soil deposits, whereby the soil loses shear strength for a short time during dynamic loading. The results of liquefaction in an earthquake are often very costly in financial terms, and can cause loss of life as well. The Kokusho Mini-Cone Triaxial Device is a one-of-a-kind device that allows for the direct correlation between two parameters of great importance in geotechnical earthquake engineering: 1) CPT (cone penetration testing) cone resistance, an empirical measure that is frequently employed in field testing of soils for geotechnical site characterization purposes; and 2) liquefaction resistance, the ability of a soil deposit to withstand the tendency for liquefaction during earthquake shaking. Professor Kokusho developed his Mini-Cone Triaxial Device in order to investigate inconsistencies that have arisen between laboratory and field data in recent liquefaction research. My role in the laboratory was twofold. The first goal was to work on laboratory testing for a research project related to aging of liquefiable sand and silt deposits. The intellectual merit of the project was to address inconsistencies in laboratory and field liquefaction data, with the aim of bettering the state of practice of mitigating liquefaction in civil engineering and therefore saving lives in future earthquakes. The second goal was to gain familiarity with the Mini-Cone Triaxial Device in hopes of developing a similar apparatus for use in America. This second goal comprises the bulk of the project's potential broader impacts. By developing a similar device for use in American research institutions, we may be able to make more advances in the study of liquefaction damage in the U.S., as well as open an avenue for further productive collaborations with Japanese researchers, who have been leaders in earthquake engineering research for decades.

Agency
National Science Foundation (NSF)
Institute
Office of International and Integrative Activities (IIA)
Application #
1107943
Program Officer
Carter Kimsey
Project Start
Project End
Budget Start
2011-06-01
Budget End
2012-05-31
Support Year
Fiscal Year
2011
Total Cost
$5,976
Indirect Cost
Name
Foster Kevin M
Department
Type
DUNS #
City
Blacksburg
State
VA
Country
United States
Zip Code
24060