Revista y Edición

AHEAD OF PRINT

Volumen 44 (2022): Edición 3 (September 2022)

Volumen 44 (2022): Edición 2 (June 2022)

Volumen 44 (2022): Edición 1 (March 2022)

Volumen 43 (2021): Edición 4 (December 2021)

Volumen 43 (2021): Edición 3 (September 2021)

Volumen 43 (2021): Edición 2 (June 2021)

Volumen 43 (2021): Edición s1 (December 2021)
Special Edición: Underground Infrastructure of Urban Areas

Volumen 43 (2021): Edición 1 (April 2021)

Volumen 42 (2020): Edición 4 (December 2020)

Volumen 42 (2020): Edición 3 (September 2020)

Volumen 42 (2020): Edición 2 (June 2020)

Volumen 42 (2020): Edición 1 (April 2020)

Volumen 41 (2019): Edición 4 (December 2019)

Volumen 41 (2019): Edición 3 (September 2019)

Volumen 41 (2019): Edición 2 (June 2019)

Volumen 41 (2019): Edición 1 (April 2019)

Volumen 40 (2018): Edición 4 (December 2018)

Volumen 40 (2018): Edición 3 (November 2018)

Volumen 40 (2018): Edición 2 (October 2018)

Volumen 40 (2018): Edición 1 (July 2018)

Volumen 39 (2017): Edición 4 (December 2017)

Volumen 39 (2017): Edición 3 (September 2017)

Volumen 39 (2017): Edición 2 (June 2017)

Volumen 39 (2017): Edición 1 (March 2017)

Volumen 38 (2016): Edición 4 (December 2016)

Volumen 38 (2016): Edición 3 (September 2016)

Volumen 38 (2016): Edición 2 (June 2016)

Volumen 38 (2016): Edición 1 (March 2016)

Volumen 37 (2015): Edición 4 (December 2015)

Volumen 37 (2015): Edición 3 (September 2015)

Volumen 37 (2015): Edición 2 (June 2015)

Volumen 37 (2015): Edición 1 (March 2015)

Volumen 36 (2014): Edición 4 (December 2014)

Volumen 36 (2014): Edición 3 (September 2014)

Volumen 36 (2014): Edición 2 (June 2014)

Volumen 36 (2014): Edición 1 (March 2014)

Volumen 35 (2013): Edición 4 (December 2013)

Volumen 35 (2013): Edición 3 (September 2013)

Volumen 35 (2013): Edición 2 (June 2013)

Volumen 35 (2013): Edición 1 (March 2013)

Volumen 34 (2012): Edición 4 (December 2012)

Volumen 34 (2012): Edición 3 (September 2012)

Volumen 34 (2012): Edición 2 (June 2012)

Volumen 34 (2012): Edición 1 (March 2012)

Detalles de la revista
Formato
Revista
eISSN
2083-831X
Publicado por primera vez
09 Nov 2012
Periodo de publicación
4 veces al año
Idiomas
Inglés

Buscar

Volumen 43 (2021): Edición 2 (June 2021)

Detalles de la revista
Formato
Revista
eISSN
2083-831X
Publicado por primera vez
09 Nov 2012
Periodo de publicación
4 veces al año
Idiomas
Inglés

Buscar

10 Artículos

Original Study

Acceso abierto

The effect of the pre-wetting of expanded clay aggregate on the freeze-thaw resistance of the expanded clay aggregate concrete

Publicado en línea: 30 Jun 2021
Páginas: 65 - 73

Resumen

Abstract

This paper presents experimental research on expanded clay aggregate concrete. The aim of the investigations was to determine if the pre-wetting of expanded clay aggregate has an effect on the freeze-thaw durability of the expanded clay aggregate concrete. Five concrete series based on the same concrete mix design were made and tested. The degree of pre-wetting of the aggregate was varied: dry aggregate was used in the first series, aggregate with a moisture content of 10% was used in series IA and IB and aggregate with a moisture content of 25% was used in series IIA and IIB. Also the approach to the production process was varied: in series A the water contained in the aggregate was taken into account in the global water-cement ratio (consequently a reduced amount of water was added to the mix), whereas in series B the nominal amount of water was added to the mix (as in the case of dry aggregate). The freeze-thaw resistance criterion was based on the assessment of the decrease of compressive strength and increase in weight loss after exposure to freeze-thaw cycles. The expanded clay aggregate concrete's strength and mass decrements caused by freeze-thaw cycling were used as the measure of its freeze-thaw resistance. The investigations have shown that the pre-wetting of expanded clay aggregate has an effect on the freeze-thaw durability of the expanded clay aggregate concrete. The differences of concrete compressive strength decrease related to freeze-thaw durability may be 2 to 5 times greater when inadequate method of calculating mixing water for concrete is used.

Palabras clave

  • lightweight concrete
  • freeze-thaw resistance
  • aggregate pre-wetting
Acceso abierto

Behaviour of eccentrically inclined loaded rectangular foundation on reinforced sand

Publicado en línea: 30 Jun 2021
Páginas: 74 - 89

Resumen

Abstract

This study presents the behaviour of model footing resting over unreinforced and reinforced sand bed under different loading conditions carried out experimentally. The parameters investigated in this study includes the number of reinforced layers (N = 0, 1, 2, 3, 4), embedment ratio (Df/B = 0, 0.5, 1.0), eccentric and inclined ratio (e/L, e/B = 0, 0.05, 0.10, 0.15) and (a = 0°, 7°, 14°). The test sand was reinforced with bi-axial geogrid (Bx20/20). The test results show that the ultimate bearing capacities decrease with axial eccentricity and inclination of applied loads. The test results also show that the depth of model footing increase zero to B (B = width of model footing), an increase of ultimate bearing capacity (UBC) approximated at 93%. Similarly, the multi-layered geogrid reinforced sand (N = 0 to 4) increases the UBC by about 75%. The bearing capacity ratio (BCR) of the model footing increases with an increasing load eccentricity to the core boundary of footing; if the load eccentricities increase continuity, the BCR decreases. The tilt of the model footing is increased by increasing the eccentricity and decreases with increasing the number of reinforcing layers.

Palabras clave

  • Eccentric loading
  • load inclination
  • ultimate bearing capacity (UBC)
  • rectangular footing
  • geogrid
Acceso abierto

Impact of subgrade and backfill stiffness on values and distribution of bending moments in integral box bridge

Publicado en línea: 30 Jun 2021
Páginas: 90 - 98

Resumen

Abstract

The article presents parametric analysis regarding the impact of subgrade and backfill stiffness on values and distribution of bending moments in the structural elements of a small integral box bridge made of cast in situ reinforced concrete. The analyzed parameters are the modulus of subgrade reaction under and behind the bridge structure (kv kh). At the beginning, the author presents the integral box bridge and selected parts of the bridge design. In particular, the author focuses on the method of modeling of the subgrade stiffness parameters under and behind the bridge structure, as well as their impact on the values and distribution of bending moments in the bridge structural elements. The bridge was designed by the author and built on the M9 motorway between the towns of Waterford and Kilcullen in Ireland. In conclusions, the author shares his knowledge and experience relating to the design of small integral bridges and culverts and puts forward recommendations as to further research on these type of structures in Poland.

Palabras clave

  • precast box bridge
  • integral bridge
  • design
  • single-span bridge
Acceso abierto

An Analytical Study of Partially Strengthened Single End-Bearing Granular Pile Near the Top and Bottom

Publicado en línea: 30 Jun 2021
Páginas: 99 - 115

Resumen

Abstract

Stone columns (or granular piles, GPs) are progressively being utilized for ground improvement, mostly for pliant edifice such as road mounds, oil depot, and so forth. The present analysis is done by introducing strengthening at both the ends of GP, i.e., bottom and top end so that the bulging problem will be solved and the beneficiary effect of the bearing stratum can be utilized by the bottom strengthening feature. Analysis of a single partially strengthened, at both top and bottom, end-bearing GP is presented in this article in terms of displacement affecting component for the top (DACT) of GP, percentage load transferred to the base (PLTB) of strengthened GP, and normalized shear stress (NSS). The PLTB of the strengthened GP was found to increase considerably. The NSS was found to reduce at the top end of GP and is found to be redistributed along the length of GP.

Palabras clave

  • granular pile
  • DACT of GP
  • NSS
  • PLTB of GP
  • reinforced stone columns
  • end-bearing GP
Acceso abierto

Application of the thermoporoelasticity model in numerical modelling of underground coal gasification influence on the surrounding medium

Publicado en línea: 30 Jun 2021
Páginas: 116 - 134

Resumen

Abstract

The purpose of this paper was to present the thermoporoelasticity model adapted for application in modelling processes, where phase transition may occur, such as during underground coal gasification (UCG). The mathematical model of the medium (soil/rock with pores filled with liquid/gas) in non-isothermal conditions is based on Biot's poroelasticity model. The poroelasticity model is expanded here by the influence of temperature and adjusted to the case where both liquid and highly compressible fluid are present in pores by using the gas laws. This requires considering temperature-dependent physical quantities such as pore fluid density, heat transfer coefficient and viscosity as functions of temperature. Based on the proposed mathematical model and the finite element method, a numerical model was built for the purpose of computing processes occurring in the vicinity of the UCG generator. The result of the authors’ work is a three-dimensional (3D) model, which was not only modified, but derived straight from the laws of thermodynamics, where fields of displacement, temperature and fluid flow are coupled. The model makes it possible to determine results significant to modelling of the UCG process, the reach of the gaseous phase's presence in pores, subsidence values, temperature distribution and directions and rate of seepage, without losing the simplicity and elegance of Biot's original concept. Next, the results of simulations for a hypothetical deposit to estimate the environmental impact of UCG are presented. After applying specific geometry and parameters, the model can be useful for verifying if the chosen technology of UCG in specific conditions will be safe for the environment and infrastructure.

Palabras clave

  • poroelasticity
  • thermoporoelasticity
  • compressible pore fluid
  • THM
  • thermo-hydro-mechanical modelling
  • UCG
  • underground coal gasification
Acceso abierto

Load capacity of the mixed bench and slab foundation. Numerical simulations and analytical calculation model

Publicado en línea: 30 Jun 2021
Páginas: 135 - 141

Resumen

Abstract

The paper presents results of a numerical investigation on load capacity of the mixed bench and slab shallow foundations (often used in the process of the modernization of the old, antique buildings, which are suffering from lack of the load capacity). The main trouble with use of existing analytical approaches is a non-unique foundation level of the bench and slab, they could even be founded on different geotechnical layers. Proposed analytical model based on Brinch Hansen (EC-7) approach could deal with such a problem. Results of 2D and 3D numerical modelling (ultimate load of the foundation) are compared to the obtained by using the proposed approach. Influence of the soil above the foundation level is also investigated. Different width to length ratios of the foundation are analyzed (from “short” to “long” foundations). Usability of the proposed analytical model in engineering practice is proved by numerical simulations; the obtained results are on the safe side with quite acceptable margin of additional safety.

Palabras clave

  • Bench and slab foundation
  • load capacity
  • numerical modelling
Acceso abierto

Termite Mound Soils for Sustainable Production of Bricks

Publicado en línea: 30 Jun 2021
Páginas: 142 - 154

Resumen

Abstract

The article presents the alternative use of termite mound soils (TMSs) as full replacement for clay soils in brick production. TMSs from two localities, Jawaj and Sene, in Ethiopia were investigated for bricks production. The TMSs samples contained high SiO2 and Al2O3. The TMSs bricks were fired at different temperatures from 500 to 1,000°C. The obtained mean compressive strengths (σ), 18 and 14 MPa, were observed for bricks made from TMSs from Jawaj and Sene, respectively, at the optimum firing temperature of 700°C. The σ of TMSs bricks decreased as the firing temperature increased above 700°C, while for conventional clay soil brick, the σ increased with temperature beyond 700°C. The water absorptions and saturation coefficients of fired TMSs bricks decreased with increased firing temperature. The TMSs bricks meet the standard specification of dimension tolerance only along the height. All the TMSs bricks made from the two localities were not efflorescent. TMSs from Jawaj and Sene sites can be used as a raw material to replace the long-used clay soils for bricks production as a construction material for houses construction in rural and urban areas.

Palabras clave

  • compressive strengths
  • chemical composition
  • firing temperature
  • sustainable production
  • termite mound soil
Acceso abierto

Geostatistical analysis of spatial variability of the liquefaction potential – Case study of a site located in Algiers (Algeria)

Publicado en línea: 30 Jun 2021
Páginas: 155 - 168

Resumen

Abstract

The city of Algiers (Algeria) is a highly seismic area, and therefore, soil liquefaction poses a major concern for structures resting on sandy soil. A campaign of 62 static penetration tests or cone penetrometer tests (CPT) was carried out on a site located in the commune of Dar El Beïda in Algiers. The soil Liquefaction Potential Index (LPI) values were assessed, for each borehole, based on the simplified procedure of Seed and Idriss. On the other hand, the geographic information system and geostatistical analysis were used to quantify the risk of soil liquefaction at the studied site. It is worth mentioning that the (LPI) was taken as a regionalized variable. In addition, the experimental variogram was modeled on the basis of a spherical model. Also, the interpolation of the LPI values in the unsampled locations was performed by the Kriging technique using both isotropic and anisotropic models. Kriging standard deviation maps were produced for both cases. The cross-validation showed that the anisotropic model exhibited a better fit for the interpolation of the values of the soil liquefaction potential. The results obtained indicated that a significant part of the soil is liable to liquefy, in particular in the northwestern region of the study area. The findings suggest that there is a proportional relationship between the risk of liquefaction and the increase or decrease in seismic acceleration.

Palabras clave

  • Potential liquefaction
  • geostatistics
  • geographic information systems
  • variogram
Acceso abierto

Laboratory tests and analysis of CIPP epoxy-resin internal liners used in pipelines – part I: comparison of tests and engineering calculations

Publicado en línea: 30 Jun 2021
Páginas: 169 - 180

Resumen

Abstract

Tests that were carried out in order to obtain knowledge of the actual values of strength parameters obtained by CIPP liners that are used to repair pipelines. Specimens of liners made of high quality polyester felt cured with epoxy resin were subjected to tests. The scope of the performed studies corresponded with the scope of acceptance tests, which are carried out in the investment process during quality control of renovation works. Specimens of liners taken from sewers with 3 different diameters, i.e. 200mm, 350mm and 500mm were selected as representative for underground sewage networks. The obtained results enabled the calculations carried out in the course of design work to be verified, and differences between the model values of the strength parameters obtained from the calculations, and real values that are burdened with irregularities resulting from the conditions prevailing at a construction site and which were obtained for specimens taken from their built-in locations to be compared.

The tests confirmed that it is possible to renovate - using CIPP liners - sewers with a lot of structural and material damage that negatively affects a liner‘s geometry. The implementation of the reinforcing internal coating in a sewer enables its further safe operation. The direct application value of the research involves the enlargement and clarification of knowledge concerning the actual load-bearing capacity of CIPP liners.

Palabras clave

  • No-dig technologies
  • laboratory tests
  • close-fit lining
  • sewer rehabilitation
Acceso abierto

Safety analysis of the Żelazny Most tailings pond: qualitative evaluation of the preventive measures effectiveness

Publicado en línea: 30 Jun 2021
Páginas: 181 - 194

Resumen

Abstract

In this paper, a qualitative safety analysis of the Żelazny Most tailings pond is addressed. This object is one of the largest facilities of this type in the world being a crucial element in the technological line of copper production in KGHM Polska Miedź S.A. The assessment of the effectiveness of two types of preventive measures, i.e., relief wells and loading berms, is investigated based on displacement and stability analysis of two 2D cross-sections in a technical section of the dam. The study shows that the considered preventive measures generally have a positive impact on increasing the safety level of the structure during its further raise. In particular, their effectiveness is most evident when they are applied simultaneously. It is eventually suggested that the selection of final solutions to be applied on the facility should be based on the quantitative 3D analysis.

Palabras clave

  • tailings pond
  • dam safety
  • loading berm
  • relief wells
10 Artículos

Original Study

Acceso abierto

The effect of the pre-wetting of expanded clay aggregate on the freeze-thaw resistance of the expanded clay aggregate concrete

Publicado en línea: 30 Jun 2021
Páginas: 65 - 73

Resumen

Abstract

This paper presents experimental research on expanded clay aggregate concrete. The aim of the investigations was to determine if the pre-wetting of expanded clay aggregate has an effect on the freeze-thaw durability of the expanded clay aggregate concrete. Five concrete series based on the same concrete mix design were made and tested. The degree of pre-wetting of the aggregate was varied: dry aggregate was used in the first series, aggregate with a moisture content of 10% was used in series IA and IB and aggregate with a moisture content of 25% was used in series IIA and IIB. Also the approach to the production process was varied: in series A the water contained in the aggregate was taken into account in the global water-cement ratio (consequently a reduced amount of water was added to the mix), whereas in series B the nominal amount of water was added to the mix (as in the case of dry aggregate). The freeze-thaw resistance criterion was based on the assessment of the decrease of compressive strength and increase in weight loss after exposure to freeze-thaw cycles. The expanded clay aggregate concrete's strength and mass decrements caused by freeze-thaw cycling were used as the measure of its freeze-thaw resistance. The investigations have shown that the pre-wetting of expanded clay aggregate has an effect on the freeze-thaw durability of the expanded clay aggregate concrete. The differences of concrete compressive strength decrease related to freeze-thaw durability may be 2 to 5 times greater when inadequate method of calculating mixing water for concrete is used.

Palabras clave

  • lightweight concrete
  • freeze-thaw resistance
  • aggregate pre-wetting
Acceso abierto

Behaviour of eccentrically inclined loaded rectangular foundation on reinforced sand

Publicado en línea: 30 Jun 2021
Páginas: 74 - 89

Resumen

Abstract

This study presents the behaviour of model footing resting over unreinforced and reinforced sand bed under different loading conditions carried out experimentally. The parameters investigated in this study includes the number of reinforced layers (N = 0, 1, 2, 3, 4), embedment ratio (Df/B = 0, 0.5, 1.0), eccentric and inclined ratio (e/L, e/B = 0, 0.05, 0.10, 0.15) and (a = 0°, 7°, 14°). The test sand was reinforced with bi-axial geogrid (Bx20/20). The test results show that the ultimate bearing capacities decrease with axial eccentricity and inclination of applied loads. The test results also show that the depth of model footing increase zero to B (B = width of model footing), an increase of ultimate bearing capacity (UBC) approximated at 93%. Similarly, the multi-layered geogrid reinforced sand (N = 0 to 4) increases the UBC by about 75%. The bearing capacity ratio (BCR) of the model footing increases with an increasing load eccentricity to the core boundary of footing; if the load eccentricities increase continuity, the BCR decreases. The tilt of the model footing is increased by increasing the eccentricity and decreases with increasing the number of reinforcing layers.

Palabras clave

  • Eccentric loading
  • load inclination
  • ultimate bearing capacity (UBC)
  • rectangular footing
  • geogrid
Acceso abierto

Impact of subgrade and backfill stiffness on values and distribution of bending moments in integral box bridge

Publicado en línea: 30 Jun 2021
Páginas: 90 - 98

Resumen

Abstract

The article presents parametric analysis regarding the impact of subgrade and backfill stiffness on values and distribution of bending moments in the structural elements of a small integral box bridge made of cast in situ reinforced concrete. The analyzed parameters are the modulus of subgrade reaction under and behind the bridge structure (kv kh). At the beginning, the author presents the integral box bridge and selected parts of the bridge design. In particular, the author focuses on the method of modeling of the subgrade stiffness parameters under and behind the bridge structure, as well as their impact on the values and distribution of bending moments in the bridge structural elements. The bridge was designed by the author and built on the M9 motorway between the towns of Waterford and Kilcullen in Ireland. In conclusions, the author shares his knowledge and experience relating to the design of small integral bridges and culverts and puts forward recommendations as to further research on these type of structures in Poland.

Palabras clave

  • precast box bridge
  • integral bridge
  • design
  • single-span bridge
Acceso abierto

An Analytical Study of Partially Strengthened Single End-Bearing Granular Pile Near the Top and Bottom

Publicado en línea: 30 Jun 2021
Páginas: 99 - 115

Resumen

Abstract

Stone columns (or granular piles, GPs) are progressively being utilized for ground improvement, mostly for pliant edifice such as road mounds, oil depot, and so forth. The present analysis is done by introducing strengthening at both the ends of GP, i.e., bottom and top end so that the bulging problem will be solved and the beneficiary effect of the bearing stratum can be utilized by the bottom strengthening feature. Analysis of a single partially strengthened, at both top and bottom, end-bearing GP is presented in this article in terms of displacement affecting component for the top (DACT) of GP, percentage load transferred to the base (PLTB) of strengthened GP, and normalized shear stress (NSS). The PLTB of the strengthened GP was found to increase considerably. The NSS was found to reduce at the top end of GP and is found to be redistributed along the length of GP.

Palabras clave

  • granular pile
  • DACT of GP
  • NSS
  • PLTB of GP
  • reinforced stone columns
  • end-bearing GP
Acceso abierto

Application of the thermoporoelasticity model in numerical modelling of underground coal gasification influence on the surrounding medium

Publicado en línea: 30 Jun 2021
Páginas: 116 - 134

Resumen

Abstract

The purpose of this paper was to present the thermoporoelasticity model adapted for application in modelling processes, where phase transition may occur, such as during underground coal gasification (UCG). The mathematical model of the medium (soil/rock with pores filled with liquid/gas) in non-isothermal conditions is based on Biot's poroelasticity model. The poroelasticity model is expanded here by the influence of temperature and adjusted to the case where both liquid and highly compressible fluid are present in pores by using the gas laws. This requires considering temperature-dependent physical quantities such as pore fluid density, heat transfer coefficient and viscosity as functions of temperature. Based on the proposed mathematical model and the finite element method, a numerical model was built for the purpose of computing processes occurring in the vicinity of the UCG generator. The result of the authors’ work is a three-dimensional (3D) model, which was not only modified, but derived straight from the laws of thermodynamics, where fields of displacement, temperature and fluid flow are coupled. The model makes it possible to determine results significant to modelling of the UCG process, the reach of the gaseous phase's presence in pores, subsidence values, temperature distribution and directions and rate of seepage, without losing the simplicity and elegance of Biot's original concept. Next, the results of simulations for a hypothetical deposit to estimate the environmental impact of UCG are presented. After applying specific geometry and parameters, the model can be useful for verifying if the chosen technology of UCG in specific conditions will be safe for the environment and infrastructure.

Palabras clave

  • poroelasticity
  • thermoporoelasticity
  • compressible pore fluid
  • THM
  • thermo-hydro-mechanical modelling
  • UCG
  • underground coal gasification
Acceso abierto

Load capacity of the mixed bench and slab foundation. Numerical simulations and analytical calculation model

Publicado en línea: 30 Jun 2021
Páginas: 135 - 141

Resumen

Abstract

The paper presents results of a numerical investigation on load capacity of the mixed bench and slab shallow foundations (often used in the process of the modernization of the old, antique buildings, which are suffering from lack of the load capacity). The main trouble with use of existing analytical approaches is a non-unique foundation level of the bench and slab, they could even be founded on different geotechnical layers. Proposed analytical model based on Brinch Hansen (EC-7) approach could deal with such a problem. Results of 2D and 3D numerical modelling (ultimate load of the foundation) are compared to the obtained by using the proposed approach. Influence of the soil above the foundation level is also investigated. Different width to length ratios of the foundation are analyzed (from “short” to “long” foundations). Usability of the proposed analytical model in engineering practice is proved by numerical simulations; the obtained results are on the safe side with quite acceptable margin of additional safety.

Palabras clave

  • Bench and slab foundation
  • load capacity
  • numerical modelling
Acceso abierto

Termite Mound Soils for Sustainable Production of Bricks

Publicado en línea: 30 Jun 2021
Páginas: 142 - 154

Resumen

Abstract

The article presents the alternative use of termite mound soils (TMSs) as full replacement for clay soils in brick production. TMSs from two localities, Jawaj and Sene, in Ethiopia were investigated for bricks production. The TMSs samples contained high SiO2 and Al2O3. The TMSs bricks were fired at different temperatures from 500 to 1,000°C. The obtained mean compressive strengths (σ), 18 and 14 MPa, were observed for bricks made from TMSs from Jawaj and Sene, respectively, at the optimum firing temperature of 700°C. The σ of TMSs bricks decreased as the firing temperature increased above 700°C, while for conventional clay soil brick, the σ increased with temperature beyond 700°C. The water absorptions and saturation coefficients of fired TMSs bricks decreased with increased firing temperature. The TMSs bricks meet the standard specification of dimension tolerance only along the height. All the TMSs bricks made from the two localities were not efflorescent. TMSs from Jawaj and Sene sites can be used as a raw material to replace the long-used clay soils for bricks production as a construction material for houses construction in rural and urban areas.

Palabras clave

  • compressive strengths
  • chemical composition
  • firing temperature
  • sustainable production
  • termite mound soil
Acceso abierto

Geostatistical analysis of spatial variability of the liquefaction potential – Case study of a site located in Algiers (Algeria)

Publicado en línea: 30 Jun 2021
Páginas: 155 - 168

Resumen

Abstract

The city of Algiers (Algeria) is a highly seismic area, and therefore, soil liquefaction poses a major concern for structures resting on sandy soil. A campaign of 62 static penetration tests or cone penetrometer tests (CPT) was carried out on a site located in the commune of Dar El Beïda in Algiers. The soil Liquefaction Potential Index (LPI) values were assessed, for each borehole, based on the simplified procedure of Seed and Idriss. On the other hand, the geographic information system and geostatistical analysis were used to quantify the risk of soil liquefaction at the studied site. It is worth mentioning that the (LPI) was taken as a regionalized variable. In addition, the experimental variogram was modeled on the basis of a spherical model. Also, the interpolation of the LPI values in the unsampled locations was performed by the Kriging technique using both isotropic and anisotropic models. Kriging standard deviation maps were produced for both cases. The cross-validation showed that the anisotropic model exhibited a better fit for the interpolation of the values of the soil liquefaction potential. The results obtained indicated that a significant part of the soil is liable to liquefy, in particular in the northwestern region of the study area. The findings suggest that there is a proportional relationship between the risk of liquefaction and the increase or decrease in seismic acceleration.

Palabras clave

  • Potential liquefaction
  • geostatistics
  • geographic information systems
  • variogram
Acceso abierto

Laboratory tests and analysis of CIPP epoxy-resin internal liners used in pipelines – part I: comparison of tests and engineering calculations

Publicado en línea: 30 Jun 2021
Páginas: 169 - 180

Resumen

Abstract

Tests that were carried out in order to obtain knowledge of the actual values of strength parameters obtained by CIPP liners that are used to repair pipelines. Specimens of liners made of high quality polyester felt cured with epoxy resin were subjected to tests. The scope of the performed studies corresponded with the scope of acceptance tests, which are carried out in the investment process during quality control of renovation works. Specimens of liners taken from sewers with 3 different diameters, i.e. 200mm, 350mm and 500mm were selected as representative for underground sewage networks. The obtained results enabled the calculations carried out in the course of design work to be verified, and differences between the model values of the strength parameters obtained from the calculations, and real values that are burdened with irregularities resulting from the conditions prevailing at a construction site and which were obtained for specimens taken from their built-in locations to be compared.

The tests confirmed that it is possible to renovate - using CIPP liners - sewers with a lot of structural and material damage that negatively affects a liner‘s geometry. The implementation of the reinforcing internal coating in a sewer enables its further safe operation. The direct application value of the research involves the enlargement and clarification of knowledge concerning the actual load-bearing capacity of CIPP liners.

Palabras clave

  • No-dig technologies
  • laboratory tests
  • close-fit lining
  • sewer rehabilitation
Acceso abierto

Safety analysis of the Żelazny Most tailings pond: qualitative evaluation of the preventive measures effectiveness

Publicado en línea: 30 Jun 2021
Páginas: 181 - 194

Resumen

Abstract

In this paper, a qualitative safety analysis of the Żelazny Most tailings pond is addressed. This object is one of the largest facilities of this type in the world being a crucial element in the technological line of copper production in KGHM Polska Miedź S.A. The assessment of the effectiveness of two types of preventive measures, i.e., relief wells and loading berms, is investigated based on displacement and stability analysis of two 2D cross-sections in a technical section of the dam. The study shows that the considered preventive measures generally have a positive impact on increasing the safety level of the structure during its further raise. In particular, their effectiveness is most evident when they are applied simultaneously. It is eventually suggested that the selection of final solutions to be applied on the facility should be based on the quantitative 3D analysis.

Palabras clave

  • tailings pond
  • dam safety
  • loading berm
  • relief wells

Planifique su conferencia remota con Sciendo