Main Article Content
The Krško-Brežice field is one of the most seismically active areas in Slovenia. The most damaging recorded earthquake with an intensity of VIII (EMS) occurred on 29th January 1917. It caused damage and claimed two lives. In the last 100 years, 9 earthquakes with intensity higher than VI (EMS) have been recorded.
At the investigated area, a top layer up to 5 m thick, consisting of recent deposit of very loose silts and sands (ML, SM, SP), covers the medium dense to dense Quaternary gravel, beneath which there are over-consolidated, uncemented Miocene silts and marls. The top layer could be prone to liquefaction, as reported for the close surroundings of Brežice, where the liquefaction phenomenon was observed during the Zagreb earthquake in 1880 and during the Kupa Valley earthquake in 1909.
The paper presents the results of laboratory index tests, cyclic simple shear tests and field investigations (SPT, CPT, (S)DMT, vs measurements), which were carried out to assess the liquefaction potential of the top layer at the location of the Brežice Hydroelectric Power Plant (HPP). All results show that the top layer is prone to liquefaction for an earthquake with a 475 year return period. Cyclic simple shear test results show that the liquefaction potential of horizontal ground for an earthquake with a 475 year return period can be reduced by the densification of the top layer to at least 95% of maximum Proctor density.
ANDRUS, R.D. & STOKOE, K.H. (2000): Liquefaction Resistance of Soils from Shear-Wave Velocity. Journal of Geotechnical and Geoenvironmental Engineering 126, 1015–1025. https://doi.org/10.1061/(ASCE)1090-0241(2000)126:11(1015)
ANDRUS, R.D., STOKOE, K.H. & HSEIN JUANG, C. (2004): Guide for Shear-Wave-Based Liquefaction Potential Evaluation. Earthq. Spectra 20, 285–308. https://doi.org/10.1193/1.1715106
ARSO (2001): Slovenian Environment Agency. http://www.arso.gov.si/potresi/podatki/projektni _pospesek_ tal.html (accessed: 29.11.2018).
ASTM D2487-10 (2010): Standard Practice for Classification of Soils for Engineering Purposes (Unified Soil Classification System), ASTM International, West Conshohocken, PA, 2010.
BOULANGER, R. & IDRISS, I. (2014): CPT and SPT based liquefaction triggering procedures. Rep No UCDCGM-14 1.
BOULANGER, R.W. & IDRISS, I.M. (2016): CPT-Based Liquefaction Triggering Procedure. J. Geotech. Geoenvironmental Eng. 142. https://doi.org/10.1061/(ASCE)GT.1943-5606.0001388
BOULANGER, R.W. & IDRISS, I.M. (2006): Liquefaction Susceptibility Criteria for Silts and Clays. J. Geotech. Geoenvironmental Eng. 132, 1413–1426. https://doi.org/10.1061/(ASCE)1090-0241(2006)132:11(1413)
BRAY, J.D., SANCIO, R.B., DURGUNOGLU, T., ONALP, A., YOUD, T.L., STEWART, J.P., SEED, R.B., CETIN, O.K., BOL, E., BATURAY, M.B., CHRISTENSEN, C. & KARADAYILAR, T. (2004): Subsurface Characterization at Ground Failure Sites in Adapazari, Turkey. J. Geotech. Geoenvironmental Eng. 130, 673–685. https://doi.org/10.1061/(ASCE)1090-0241(2004)130:7(673)
CHU, D.B., STEWART, J.P., LEE, S., TSAI, J.S., LIN, P.S., CHU, B.L., SEED, R.B., HSU, S.C., YU, M.S. & WANG, M.C.H. (2004): Documentation of soil conditions at liquefaction and non-liquefaction sites from 1999 Chi–Chi (Taiwan) earthquake. Soil Dyn. Earthq. Eng. 24, 647–657. https://doi.org/10.1016/j.soildyn.2004.06.005
CUBRINOVSKI, M., RHODES, A., DE LA TORRE, C., BRAY, J. & NTRITSOS, N. (2018): Liquefaction Hazards from “Inherited Vulnerabilities.” ce/papers 2, 39–54. https://doi.org/10.1002/cepa.661
DAS, B.M. (1992): Principles of Soil Dynamics, 1st edition. Thomson-Engineering.
DIN 18127 (2012): Soil, investigation and testing - Proctor-test.
HERAK, D., HERAK, M. & TOMLJENOVIĆ, B. (2009): Seismicity and earthquake focal mechanisms in North-Western Croatia. Tectonophysics 465, 212–220. https://doi.org/10.1016/j.tecto.2008.12.005
HERAK, D. & HERAK, M. (2010) The Kupa Valley (Croatia) Earthquake of 8 October 1909—100 Years Later. Seismol. Res. Lett. 81, 30. https://doi.org/10.1785/gssrl.81.1.30
HOSONO, Y. & YOSHIMINE, M. (2004): Liquefaction of sand in simple shear condition. In Proceedings of the International Conference on Cyclic Behaviour of Soils and Liquefaction Phenomena, Bochum, Germany, 31 March – 02 April 2004. A.A. Balkema, Rotterdam: 129–136 str.
IDRISS, I. M. (1999): An update to the Seed-Idriss simplified procedure for evaluating liquefaction potential, in Proceedings, TRB Workshop on New Approaches to Liquefaction, Publication No. FHWARD-99-165, Federal Highway Administration.
IDRISS, I.M. & BOULANGER, R.W. (2006): Semi-empirical procedures for evaluating liquefaction potential during earthquakes. Soil Dyn. Earthq. Eng. 26, 115–130. https://doi.org/10.1016/j.soildyn.2004.11.023
IDRISS, I.M. & BOULANGER, R.W. (2010): SPT based liquefaction triggering procedures. Report No. UCD/CGM-10-02. Center for Geotechnical Modeling, Department of Civil and Environmental Engineering, University of California. Davis, California.
ISHIHARA, K., TRONCOSO, J., KAWASE, Y. & TAKAHASHI, Y. (1980): Cyclic strength characteristics of tailings materials. Soils and Foundations, 20(4), pp. 127-142.
IWASAKI, T., ARAKAWA, T. & TOKIDA, K.-I. (1984): Simplified procedures for assessing soil liquefaction during earthquakes. Int. J. Soil Dyn. Earthq. Eng. 3, 49–58. https://doi.org/10.1016/0261-7277(84)90027-5
KRAMER, S.L. (1996): Geotechnical Earthquake Engineering. Prentice Hall.
LAI, C. G., MEISINA, C., COSENTINI R. M., BOZZONI, F., PERSICHILLO, P., BORDONI, M., TUMIATI, M., VIANA DA FONSECA, A., FERREIRA, C., RAMOS, C., PETKOVŠEK, A., SMOLAR, J., OBLAK, A., MAČEK, M., KOSIČ, M., KUDER, S., PETROVIČ, D., DOLŠEK, M., LESJAK, M., ZAKONJŠEK, D., LESJAK, I., STRNIŠA, G., PADOVAN, B., LOGAR, J., OZCEP, F., OZTOPRAK, S., BOZBEY, I., AYSAL, N., OSER, C., SARGIN, S., TEZEL, O., CINKU, M. & OZDEMIR, K. (2017): Report on ground characterization of the four areas selected as testing sites by using novel technique and advances metodologies to perform in situ and laboratory tests. Deliverable D2.1. V 1.0. Project Liquefact, H2020-DRA-2015, GA no. 700748.
MARCHETTI, D. & MARCHETTI, S. (2016): Flat Dilatometer (DMT). Some Recent Advances. Procedia Eng. 158, 428–433. https://doi.org/10.1016/j.proeng.2016.08.467
PETKOVŠEK, A., MAČEK, M. & SMOLAR, J. (2017): Testing methods for mechanically improved soils: RELIABILITY AND VALIDITY. Acta Polytech. CTU Proc. 10, 16–33. https://doi.org/10.14311/APP.2017.10.0016
POLITO, C.P. & MARTIN, J.R. (2001): Effects of Nonplastic Fines on the Liquefaction Resistance of Sands. J. Geotech. Geoenvironmental Eng. 127, 408–415. https://doi.org/10.1061/(ASCE)1090-0241(2001)127:5(408)
ROBERTSON, P.K. (2012): Interpretation of in-situ tests – some insights, in: Proc. 4 Int. Conf. on Site Characterization. Presented at the ISC’4, Brazil.
ROLLINS, K.M. & REMUND, T.K. (2016): Evaluation of DMT liquefaction triggering curves based on field case histories, in: Geotechnical and Geophysical Site Characterization 5. Sydney.
SHENGCONG, F. & TATSUOKA, F. (1984): Soil liquefaction during Haicheng and Tangshan Earthquake in China; A review. SOILS Found. 24, 11–29. https://doi.org/10.3208/sandf1972.24.4_11.
SIST EN ISO 22476-3 (2005): Geotechnical investigation and testing - Field testing - Part 3: Standard penetration test (ISO 22476-3:2005).
SIST EN ISO 22476-1 (2013): Geotechnical investigation and testing - Field testing - Part 1: Electrical cone and piezocone penetration test (ISO 22476-1:2012).
SIST-TS CEN ISO/TS 17892-1 (2004): Geotechnical investigation and testing - Laboratory testing of soil - Part 1: Determination of water content (ISO 17892-1:2014).
SIST-TS CEN ISO/TS 17892-2 (2004): Geotechnical investigation and testing - Laboratory testing of soil - Part 2: Determination of bulk density (ISO/TS 17892-2:2004).
SIST-TS CEN ISO/TS 17892-3 (2004): Geotechnical investigation and testing - Laboratory testing of soil - Part 3: Determination of particle density - Pycnometer method (ISO/TS 17892-3:2004).
SIST-TS CEN ISO/TS 17892-4 (2004): Geotechnical investigation and testing - Laboratory testing of soil - Part 4: Determination of particle size distribution (ISO/TS 17892-4:2004).
SIST-TS CEN ISO/TS 17892-12 (2004): Geotechnical investigation and testing - Laboratory testing of soil - Part 12: Determination of Atterberg limits (ISO/TS 17892-12:2004).
SIST-TS CEN ISO/TS 22476-11 (2008): Geotechnical investigation and testing - Field testing - Part 11: Flat dilatometer test (ISO 22476-11:2005).
VEINOVIĆ, Ž., DOMITROVIĆ, D. & LOVRIĆ, T. (2007): Pojava likvefakcije na području Zagreba u prošlosti i procjena mogićnosti ponovne pojave tjekom jačeg potresa. Rud.-Geol.-Naft. Zb. 19, 111–120.
VUKADIN, V. (2013): The improvement of the loosely deposited sands and silts with the Rapid Impact Compaction technique on Brežice test sites. Engineering Geology 160, 69–80. https://doi.org/10.1016/j.enggeo.2013.03.025
YOUD, T.L., IDRISS, I.M., ANDRUS, R.D., ARANGO, I., CASTRO, G., CHRISTIAN, J.T., DOBRY, R., FINN, W.D.L., HARDER, L.F., HYNES, M.E., ISHIHARA, K., KOESTER, J.P., LIAO, S.S.C., MARCUSON, W.F., MARTIN, G.R., MITCHELL, J.K., MORIWAKI, Y., POWER, M.S., ROBERTSON, P.K., SEED, R.B. & STOKOE, K.H. (2001): Liquefaction Resistance of Soils: Summary Report from the 1996 NCEER and 1998 NCEER/NSF Workshops on Evaluation of Liquefaction Resistance of Soils. J. Geotech. Geoenvironmental Eng. 127, 817–833. https://doi.org/10.1061/(ASCE)1090-0241(2001)127:10(817)