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Papers by Jana Frankovska
The reservoir Nová Bystrica is located in the northern part of Slovakia, about 6 km southward of ... more The reservoir Nová Bystrica is located in the northern part of Slovakia, about 6 km southward of the border with Poland (fi g. 1). It is used to supply the population with drinking water and was put into operation in 1989. Rock environment of the area consists of rocks belonging to Outer Flysch Zone. The fl ysch formation is characteristic by the alternation of pelite (clay stone, marly soil and siltstone) with sandstone. The most dominant strike of the fl ysch layers is E–W, while their dip is almost vertical (80–90°). The formation has due to multiple folding of the area complex over thrust structure.
Slovak Journal of Civil Engineering
The article is focused on a regression analysis of small strain shear and constrained modulus mea... more The article is focused on a regression analysis of small strain shear and constrained modulus measurements of 15 different natural sands with plastic fines from the Pannonian basin. Measurements done within this work are supported by additional data on sands with plastic and non-plastic fines gathered from the literature in order to demonstrate the versatility of the approaches used and behavior observed. Bender / extender element techniques are used in this study for measuring the small strain shear and constrained modulus of sands with fines. Three void ratio functions, which are commonly used in predictive empirical equations for predicting small strain stiffness, with corresponding fitted parameters are presented, and their effect on the accuracy of the regression procedure is studied. It is assumed that all the void ratio functions tested provide nearly the same degree of accuracy and that the fitted models are able to predict the values of the parameters measured within an acc...
Procedia Engineering, 2016
Japanese Geotechnical Society Special Publication, 2016
The Continuous Flight Auger (CFA) technology has evolved especially in recent decades. Using of C... more The Continuous Flight Auger (CFA) technology has evolved especially in recent decades. Using of CFA technology has expanded all over the world. The article deals with geotechnical design of pile foundations, especially by static load tests and by calculation using numerical models. Results of static load tests which were performed in and in Slovakia are analysed and compared with numerical modelling. The technology of CFA has been used due to the advantages of this technology in comparison with driven and bored piles in local geotechnical conditions. Plaxis 2011 was used for CFA piles analyses by FEM. Advanced constitutive hardening soil model was used for soil layers. Comparison of load-settlement curves, ratio of pile base and pile shaft resistance and distribution of unit shaft friction are presented in the paper. The best geoengineering solution in this case is the use of new pile technology CFA (continuous flight auger), FDP (full displacement piles), DDS (drilling displacement system), that lead to increased bearing capacity.
14th SGEM GeoConference on SCIENCE AND TECHNOLOGIES IN GEOLOGY, EXPLORATION AND MINING, 2014
Procedia Earth and Planetary Science, 2015
Genesis and Properties of Collapsible Soils, 1995
Research for the deep geological repository (DGR) started in Slovakia in 1996. Results of the eng... more Research for the deep geological repository (DGR) started in Slovakia in 1996. Results of the engineering geological research of the clay in both, the natural and engineered barriers are summarized in the paper. The Szécsény Schlier from the Lučenec Formation is a potential sedimentary host rock for the DGR in Slovakia of favourable properties, similar to a natural clay barrier. It is a friable calcareous siltstone with intercalations of silty clay and fine-grained sandstone, of low hydraulic conductivity (k≅10-10 m.s-1) and acceptable uniaxial compessive strength (from 18.5 to 34.8 MPa). Engineering geological characterisation of this formation is based upon rock samples collected from boreholes and tested in the laboratory. Several deposits in Slovakia might offer suitable buffer/backfill material for engineered barriers of the DGR. Since 2003 five bentonite types have been studied, selected results of the engineering geological evaluation are discussed in this paper. Liquid limit...
Acta Geologica Slovaca, Jun 15, 2014
For weak and soft rocks, i.e. rocks with the uniaxial compressive strength less than 50 MPa, the ... more For weak and soft rocks, i.e. rocks with the uniaxial compressive strength less than 50 MPa, the Point Load Test is often the only way to determine their strength properties. Despite the indisputable advantages of this test, the value of the conversion factor K between the results of this test, the point load index, and the uniaxial compressive strength, which is used as classification property, is permanently analysed and discussed. The experiences from the field engineering geological investigations show that the conversion factor K for soft and weak rocks is usually less than 22, what is the value stated in EN 1926, Slovak Standard STN 72 1001 or in suggested methods of ISRM. The necessity of individual approach to determine geotechnical characteristics of weak or soft rocks is documented on some examples from the ground investigation for the Highway D1 in Slovakia. The value of the conversion factor K for weathered marlstones and marly or sandy limestones in the section Turany-Hubová of the D1 Highway in the route of the designed tunnel Havran was about 14, in the section Jánovce-Jablonov for weathered sandstones it reached about 19. In another case the conversion factor 18 or 20 should be used for weathered and altered granite, granodiorite and pegmatite rocks from the Bratislava territory for the purpose of correct classification of rocks.
Acta Geologica Slovaca, Jun 15, 2014
For weak and soft rocks, i.e. rocks with the uniaxial compressive strength less than 50 MPa, the ... more For weak and soft rocks, i.e. rocks with the uniaxial compressive strength less than 50 MPa, the Point Load Test is often the only way to determine their strength properties. Despite the indisputable advantages of this test, the value of the conversion factor K between the results of this test, the point load index, and the uniaxial compressive strength, which is used as classification property, is permanently analysed and discussed. The experiences from the field engineering geological investigations show that the conversion factor K for soft and weak rocks is usually less than 22, what is the value stated in EN 1926, Slovak Standard STN 72 1001 or in suggested methods of ISRM. The necessity of individual approach to determine geotechnical characteristics of weak or soft rocks is documented on some examples from the ground investigation for the Highway D1 in Slovakia. The value of the conversion factor K for weathered marlstones and marly or sandy limestones in the section Turany-Hubová of the D1 Highway in the route of the designed tunnel Havran was about 14, in the section Jánovce-Jablonov for weathered sandstones it reached about 19. In another case the conversion factor 18 or 20 should be used for weathered and altered granite, granodiorite and pegmatite rocks from the Bratislava territory for the purpose of correct classification of rocks.
Research for the deep geological repository (DGR) started in Slovakia in 1996. Results of the eng... more Research for the deep geological repository (DGR) started in Slovakia in 1996. Results of the engineering geological research of the clay in both, the natural and engineered barriers are summarized in the paper. The Szécsény Schlier from the Lučenec Formation is a potential sedimentary host rock for the DGR in Slovakia of favourable properties, similar to a natural clay barrier. It is a friable calcareous siltstone with intercalations of silty clay and fine-grained sandstone, of low hydraulic conductivity (k≅10-10 m.s-1) and acceptable uniaxial compessive strength (from 18.5 to 34.8 MPa). Engineering geological characterisation of this formation is based upon rock samples collected from boreholes and tested in the laboratory. Several deposits in Slovakia might offer suitable buffer/backfill material for engineered barriers of the DGR. Since 2003 five bentonite types have been studied, selected results of the engineering geological evaluation are discussed in this paper. Liquid limit...
Geosynthetics International, 2010
Sodium bentonite (Na-bentonite) is used as a sealing component in geosynthetic clay liners (GCL).... more Sodium bentonite (Na-bentonite) is used as a sealing component in geosynthetic clay liners (GCL). Na-bentonite is very sensitive to chlorides, and flocculation occurs when it is exposed to saline environments. The purpose of this work is to investigate the properties of Nabentonite and bentonite-palygorskite filler material for GCL in saline solutions in the range between 0.5% and 10% (0.09 and 1.8 M) NaCl concentration. The investigation has been carried out to evaluate and study the chemical and geotechnical properties of Na-bentonite and bentonitepalygorskite mixture. The observations suggest that the resistance of Na-bentonite to chlorides is increased by adding 40% palygorskite. The bentonite-palygorskite mixture is characterised by high liquid and plastic limits, and also by high water adsorption and free swell in water, crude oil and petrol. Hydraulic conductivity was determined for water and for 10% NaCl (1.80 M) solution. The results show that Na-bentonite palygorskite mixture serves as an effective absorber of both water and saline solutions up to a concentration of 10% (1.80 M) of NaCl without increasing the hydraulic conductivity.
Applied Clay Science, 2005
Ca-bentonite with 68% and 92% of smectite, and Na-bentonite with 68% and 92% of smectite were stu... more Ca-bentonite with 68% and 92% of smectite, and Na-bentonite with 68% and 92% of smectite were studied by XRD, chemical analysis and scanning electron microscopy (SEM) to evaluate differences in microstructure formation and geotechnical properties. Plasticity and liquid limit, water adsorption by Enslin test, free swell test and standard swell test were performed, as well as the determination of ignition loss and permeability test.
The reservoir Nová Bystrica is located in the northern part of Slovakia, about 6 km southward of ... more The reservoir Nová Bystrica is located in the northern part of Slovakia, about 6 km southward of the border with Poland (fi g. 1). It is used to supply the population with drinking water and was put into operation in 1989. Rock environment of the area consists of rocks belonging to Outer Flysch Zone. The fl ysch formation is characteristic by the alternation of pelite (clay stone, marly soil and siltstone) with sandstone. The most dominant strike of the fl ysch layers is E–W, while their dip is almost vertical (80–90°). The formation has due to multiple folding of the area complex over thrust structure.
Slovak Journal of Civil Engineering
The article is focused on a regression analysis of small strain shear and constrained modulus mea... more The article is focused on a regression analysis of small strain shear and constrained modulus measurements of 15 different natural sands with plastic fines from the Pannonian basin. Measurements done within this work are supported by additional data on sands with plastic and non-plastic fines gathered from the literature in order to demonstrate the versatility of the approaches used and behavior observed. Bender / extender element techniques are used in this study for measuring the small strain shear and constrained modulus of sands with fines. Three void ratio functions, which are commonly used in predictive empirical equations for predicting small strain stiffness, with corresponding fitted parameters are presented, and their effect on the accuracy of the regression procedure is studied. It is assumed that all the void ratio functions tested provide nearly the same degree of accuracy and that the fitted models are able to predict the values of the parameters measured within an acc...
Procedia Engineering, 2016
Japanese Geotechnical Society Special Publication, 2016
The Continuous Flight Auger (CFA) technology has evolved especially in recent decades. Using of C... more The Continuous Flight Auger (CFA) technology has evolved especially in recent decades. Using of CFA technology has expanded all over the world. The article deals with geotechnical design of pile foundations, especially by static load tests and by calculation using numerical models. Results of static load tests which were performed in and in Slovakia are analysed and compared with numerical modelling. The technology of CFA has been used due to the advantages of this technology in comparison with driven and bored piles in local geotechnical conditions. Plaxis 2011 was used for CFA piles analyses by FEM. Advanced constitutive hardening soil model was used for soil layers. Comparison of load-settlement curves, ratio of pile base and pile shaft resistance and distribution of unit shaft friction are presented in the paper. The best geoengineering solution in this case is the use of new pile technology CFA (continuous flight auger), FDP (full displacement piles), DDS (drilling displacement system), that lead to increased bearing capacity.
14th SGEM GeoConference on SCIENCE AND TECHNOLOGIES IN GEOLOGY, EXPLORATION AND MINING, 2014
Procedia Earth and Planetary Science, 2015
Genesis and Properties of Collapsible Soils, 1995
Research for the deep geological repository (DGR) started in Slovakia in 1996. Results of the eng... more Research for the deep geological repository (DGR) started in Slovakia in 1996. Results of the engineering geological research of the clay in both, the natural and engineered barriers are summarized in the paper. The Szécsény Schlier from the Lučenec Formation is a potential sedimentary host rock for the DGR in Slovakia of favourable properties, similar to a natural clay barrier. It is a friable calcareous siltstone with intercalations of silty clay and fine-grained sandstone, of low hydraulic conductivity (k≅10-10 m.s-1) and acceptable uniaxial compessive strength (from 18.5 to 34.8 MPa). Engineering geological characterisation of this formation is based upon rock samples collected from boreholes and tested in the laboratory. Several deposits in Slovakia might offer suitable buffer/backfill material for engineered barriers of the DGR. Since 2003 five bentonite types have been studied, selected results of the engineering geological evaluation are discussed in this paper. Liquid limit...
Acta Geologica Slovaca, Jun 15, 2014
For weak and soft rocks, i.e. rocks with the uniaxial compressive strength less than 50 MPa, the ... more For weak and soft rocks, i.e. rocks with the uniaxial compressive strength less than 50 MPa, the Point Load Test is often the only way to determine their strength properties. Despite the indisputable advantages of this test, the value of the conversion factor K between the results of this test, the point load index, and the uniaxial compressive strength, which is used as classification property, is permanently analysed and discussed. The experiences from the field engineering geological investigations show that the conversion factor K for soft and weak rocks is usually less than 22, what is the value stated in EN 1926, Slovak Standard STN 72 1001 or in suggested methods of ISRM. The necessity of individual approach to determine geotechnical characteristics of weak or soft rocks is documented on some examples from the ground investigation for the Highway D1 in Slovakia. The value of the conversion factor K for weathered marlstones and marly or sandy limestones in the section Turany-Hubová of the D1 Highway in the route of the designed tunnel Havran was about 14, in the section Jánovce-Jablonov for weathered sandstones it reached about 19. In another case the conversion factor 18 or 20 should be used for weathered and altered granite, granodiorite and pegmatite rocks from the Bratislava territory for the purpose of correct classification of rocks.
Acta Geologica Slovaca, Jun 15, 2014
For weak and soft rocks, i.e. rocks with the uniaxial compressive strength less than 50 MPa, the ... more For weak and soft rocks, i.e. rocks with the uniaxial compressive strength less than 50 MPa, the Point Load Test is often the only way to determine their strength properties. Despite the indisputable advantages of this test, the value of the conversion factor K between the results of this test, the point load index, and the uniaxial compressive strength, which is used as classification property, is permanently analysed and discussed. The experiences from the field engineering geological investigations show that the conversion factor K for soft and weak rocks is usually less than 22, what is the value stated in EN 1926, Slovak Standard STN 72 1001 or in suggested methods of ISRM. The necessity of individual approach to determine geotechnical characteristics of weak or soft rocks is documented on some examples from the ground investigation for the Highway D1 in Slovakia. The value of the conversion factor K for weathered marlstones and marly or sandy limestones in the section Turany-Hubová of the D1 Highway in the route of the designed tunnel Havran was about 14, in the section Jánovce-Jablonov for weathered sandstones it reached about 19. In another case the conversion factor 18 or 20 should be used for weathered and altered granite, granodiorite and pegmatite rocks from the Bratislava territory for the purpose of correct classification of rocks.
Research for the deep geological repository (DGR) started in Slovakia in 1996. Results of the eng... more Research for the deep geological repository (DGR) started in Slovakia in 1996. Results of the engineering geological research of the clay in both, the natural and engineered barriers are summarized in the paper. The Szécsény Schlier from the Lučenec Formation is a potential sedimentary host rock for the DGR in Slovakia of favourable properties, similar to a natural clay barrier. It is a friable calcareous siltstone with intercalations of silty clay and fine-grained sandstone, of low hydraulic conductivity (k≅10-10 m.s-1) and acceptable uniaxial compessive strength (from 18.5 to 34.8 MPa). Engineering geological characterisation of this formation is based upon rock samples collected from boreholes and tested in the laboratory. Several deposits in Slovakia might offer suitable buffer/backfill material for engineered barriers of the DGR. Since 2003 five bentonite types have been studied, selected results of the engineering geological evaluation are discussed in this paper. Liquid limit...
Geosynthetics International, 2010
Sodium bentonite (Na-bentonite) is used as a sealing component in geosynthetic clay liners (GCL).... more Sodium bentonite (Na-bentonite) is used as a sealing component in geosynthetic clay liners (GCL). Na-bentonite is very sensitive to chlorides, and flocculation occurs when it is exposed to saline environments. The purpose of this work is to investigate the properties of Nabentonite and bentonite-palygorskite filler material for GCL in saline solutions in the range between 0.5% and 10% (0.09 and 1.8 M) NaCl concentration. The investigation has been carried out to evaluate and study the chemical and geotechnical properties of Na-bentonite and bentonitepalygorskite mixture. The observations suggest that the resistance of Na-bentonite to chlorides is increased by adding 40% palygorskite. The bentonite-palygorskite mixture is characterised by high liquid and plastic limits, and also by high water adsorption and free swell in water, crude oil and petrol. Hydraulic conductivity was determined for water and for 10% NaCl (1.80 M) solution. The results show that Na-bentonite palygorskite mixture serves as an effective absorber of both water and saline solutions up to a concentration of 10% (1.80 M) of NaCl without increasing the hydraulic conductivity.
Applied Clay Science, 2005
Ca-bentonite with 68% and 92% of smectite, and Na-bentonite with 68% and 92% of smectite were stu... more Ca-bentonite with 68% and 92% of smectite, and Na-bentonite with 68% and 92% of smectite were studied by XRD, chemical analysis and scanning electron microscopy (SEM) to evaluate differences in microstructure formation and geotechnical properties. Plasticity and liquid limit, water adsorption by Enslin test, free swell test and standard swell test were performed, as well as the determination of ignition loss and permeability test.