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Title: ASSESSMENT OF THE NAKAMURA'S VULNERABILITY INDEX OF AN EARTHEN DAM, FROM AMBIENT NOISE RECORDINGS
ASSESSMENT OF THE NAKAMURA'S VULNERABILITY INDEX OF AN EARTHEN DAM, FROM AMBIENT NOISE RECORDINGS

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Emil Oynakov; Radan Ivanov; Irena Aleksandrova; Yordan Milkov; Maria Popova
10.5593/sgem2023/1.1/s02.23
10.5593/sgem2023/1.1
1314-2704
978-619-7603-56-9
English
23
1
•    Prof. DSc. Oleksandr Trofymchuk, UKRAINE 
•    Prof. Dr. hab. oec. Baiba Rivza, LATVIA
Hydrogeology, Engineering Geology and Geotechnics
Among the important parameters determining the likelihood of occurrence of significant damage to engineering structures during an earthquake are the dynamic and seismic characteristics of the structures such as natural frequency, damping coefficient, and vulnerability index of the structure.
In this article, the Nakamura method is applied to investigate the seismic stability of an earth-filled dam wall and the surface layer using microtremors. Measurements were taken at seven points on the dam crest and three points at its base. All measurements were taken using two mobile accelerometers (ETNA 2), with a recording frequency of 100 samples/second. The recording time at each point was 20 minutes. The accelerometer's y axis was aligned with the dam crest’s normal, and the x axis was parallel to the wall. The data was processed using the GEOPSY v.3.4.1 program, by which a geotechnical test was performed for the site – computation of the horizontal to vertical spectral ratio (HVSR). Graphs of the spectral H/V ratios for each observation point were made. The vulnerability indices for each point were calculated.
Using the obtained vulnerability indices, it was shown that neither the dam nor its base layer are likely to suffer damage due to an earthquake with peak ground acceleration of 0.37g., which is the design event for the region where the dam is located. The study is the first of its kind in Bulgaria, and was carried out in full by the authors.
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The presented work was performed within the project Assessment of Earthquake Ground Motion Amplification in the Sofia Basin, funded by the Bulgarian National Science Fund, contract number KП-06-Н64/1 from 15.12.2022.
conference
https://doi.org/10.5593/sgem2023/1.1/s02.23
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Proceedings of 23rd International Multidisciplinary Scientific GeoConference SGEM 2023
23rd International Multidisciplinary Scientific GeoConference SGEM 2023, 03 - 09 July, 2023
Proceedings Paper
STEF92 Technology
International Multidisciplinary Scientific GeoConference-SGEM
SWS Scholarly Society; Acad Sci Czech Republ; Latvian Acad Sci; Polish Acad Sci; Russian Acad Sci; Serbian Acad Sci and Arts; Natl Acad Sci Ukraine; Natl Acad Sci Armenia; Sci Council Japan; European Acad Sci, Arts and Letters; Acad Fine Arts Zagreb Croatia; Croatian Acad Sci and Arts; Acad Sci Moldova; Montenegrin Acad Sci and Arts; Georgian Acad Sci; Acad Fine Arts and Design Bratislava; Russian Acad Arts; Turkish Acad Sci.
191-198
03 - 09 July, 2023
website
9012
Vulnerability index, K-values, microtremor, earthquake, H/V spectral ratio