DBPapers
DOI: 10.5593/sgem2017/12/S02.064

LIQUEFACTION SUSCEPTIBILITY OF QUATERNARY DEPOSITS IN BULGARIA

B. Berov, P. Ivanov, G. Frangov, N. Dobrev, M. Krastanov
Sunday 10 September 2017 by Libadmin2017

References: 17th International Multidisciplinary Scientific GeoConference SGEM 2017, www.sgem.org, SGEM2017 Conference Proceedings, ISBN 978-619-7105-99-5 / ISSN 1314-2704, 29 June - 5 July, 2017, Vol. 17, Issue 12, 499-506 pp, DOI: 10.5593/sgem2017/12/S02.064

ABSTRACT

Bulgarian territory is subjected to impact of almost all negative and destructive geological processes and phenomena. The engineering estimation of these hazards requires knowledge of their origin, evaluation of potential occurrence of these phenomena, and their resulting risk.
The liquefaction of weak soils under dynamic impacts is one of the processes that compose the geological hazards. This phenomenon occurs in certain areas during strong earthquakes. It involves a loss of bearing capacity of sediments, terrain deformations, tilting, cracking and demolition of buildings and facilities.
Liquefaction of weak soils in Bulgaria is registered during the all major earthquakes with magnitude above 5, both from local and regional sources. The processes of liquefaction can cover large areas and significantly increase the destructive effect of earthquakes. Liquefaction events are observed mainly in the Danubian Plain; in the terrace of Golyama River (Strazhitsa area); in the terraces of the Iskar River (Sofia) and the Maritsa River (between Chirpan and Plovdiv); in the terraces of Yantra (at Gorna Oryahovitsa); and in sand strips in the regions of Burgas and Varna in coastal estuaries.
During this study, a characteristic of the geological environment that is favorable for the occurrence of these phenomena was done, as well as the factors for their occurrence and methods of determining the conditions for liquefaction.
Several key criteria are applied in assessing the susceptibility to liquefaction, including historical, geomorphological and geological reasons for the composition and condition of the soils. These criteria were used in creating a map of liquefaction susceptibility of weak soils in Bulgaria. Near-surface geological environment is the most susceptible to liquefaction. A zoning of the country for liquefaction potential has been made on this basis.

Keywords: Soil liquefaction, Liquefaction susceptibility, Geological hazards, Quaternary Deposits, Bulgaria