Geotechnical parameters of loess-cement mixture for construction of compacted soil-cement cushion

Pages: 
pp. 117-124
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
Abstract: 

Soil-cement cushions are compacted and stabilized layers of the soil base, built under the foundation. Usually, they are constructed with local soil from the excavation, mixed with Portland cement. In Bulgaria, this soil improvement technique has been applied in foundation works in collapsible loess ground, aiming to replace a part of the collapsible layer, to increase the bearing capacity of the soil base, and/or to play a role of engineering barrier against migration of harmful substances in the geoenvironment. A multi-barrier near-surface short-lived low- and intermediate-level radioactive waste repository is under construction in Bulgaria. A loess-cement cushion beneath repository cells is going to be built by in-situ compacted mixture of local loess and Portland cement. Based on the results from classification and physico-mechanical tests of a set of loess-cement mixtures, it was proposed optimum cement content of the loess-cement cushion beneath the radioactive waste repository to be 5% of Portland cement. The present paper aims to assess the following geotechnical parameters of the selected loess-cement mixture after proper curing: unconfined compressive and flexural strength; shear strength parameters; static and dynamic elastic constants; and hydraulic conductivity. The results obtained prove that the mixture prepared at Wopt and ρds of local loess and 5% (by the dry weight of soil) of Portland cement type CEM I 42.5 N – SR 5 possesses strength and deformation characteristics that completely meet the design stress-strain requirements to the soil-cement cushion beneath the repository foundation.

Keywords: 

soil stabilization, loess-cement cushion, geotechnical parameters

VOLUME 46 (2)/November 2017 125th Anniversary of Acad. Strashimir Dimitrov; 70th Anniversary of the Geological Institute, Bulgarian Academy of Sciences

University of Mining and Geology, Department of Geology and Geoinformatics, Studentski Grad, Prof. Boyan Kamenov Str., 1700 Sofia, Bulgaria; Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Ellatzite-Med PLC, 2086 Mirkovo, Sofia District, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 11, 1113 Sofia
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Institute of General and Inorganic Chemistry, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 11, 1113 Sofia

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute “Strashimir Dimitrov”, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Department of Geology, Palaeontology and Fossil Fuels, Sofia University, 15 Tzar Osvoboditel Blvd, 1000 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Polish Geological Institute – National Research Institute, Rakowiecka 4, 00-975 Warszawa, Poland
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Comenius University, Faculty of Natural Sciences, Department of Geology and Palaeontology, Mlynská dolina G–229, Ilkovičova 6, SK-84215 Bratislava, Slovak Republic
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Polish Geological Institute – National Research Institute, Rakowiecka 4, 00-975 Warszawa, Poland
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Institute of Geology, Academy of Sciences of the Czech Republic, v.v.l., Rozvojová, 269,165 000 Praha 6, Czech Republic

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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University of Sofia “St Kliment Ohridski”, Faculty of History, Department of Archaeology, 15 Tsar Osvoboditel Blvd, 1000 Sofia, Bulgaria
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University of Sofia “St Kliment Ohridski”, Faculty of History, Department of Archaeology, 15 Tsar Osvoboditel Blvd, 1000 Sofia, Bulgaria
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National Institute of Archaeology and Museum, Bulgarian Academy of Sciences, Department of Prehistory, 2 Saborna Str., 1000 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Block 24, 1113 Sofia, Bulgaria
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National Institute of Meteorology and Hydrology, 66 Tsarigradsko Shose Blvd, 1784 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Faculty of Geology and Geography, Department of Geology, Palaeontology and Fossil Fuels, Sofia University “St Kliment Ohridski, 15 Tsar Osvoboditel Blvd, 1504 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 24, Sofia 1113, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 24, Sofia 1113, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 24, Sofia 1113, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 24, Sofia 1113, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 24, Sofia 1113, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 24, Sofia 1113, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

University of Mining and Geology, Prof. B. Kamenov Str., Sofia, 1700. Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 24, Sofia 1113, Bulgaria
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University of Mining and Geology, Prof. B. Kamenov Str., Sofia, 1700. Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev St., Block 24, Sofia 1113, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria
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Austrian Institute of Technology, Center for Energy, Konrad-Lorenz-Str. 24, 3430 Tulln, Austria
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Austrian Institute of Technology, Center for Energy, Konrad-Lorenz-Str. 24, 3430 Tulln, Austria
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Austrian Institute of Technology, Center for Energy, Konrad-Lorenz-Str. 24, 3430 Tulln, Austria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev, Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev, Bl. 24, 1113 Sofia, Bulgaria; Institute of Geochemistry and Petrology, ETH, 8092 Zurich, Switzerland
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Institute of Geochemistry and Petrology, ETH, 8092 Zurich, Switzerland
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev, Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev, Bl. 24, 1113 Sofia, Bulgaria