Zeszyty czasopisma

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Tom 44 (2022): Zeszyt 3 (September 2022)

Tom 44 (2022): Zeszyt 2 (June 2022)

Tom 44 (2022): Zeszyt 1 (March 2022)

Tom 43 (2021): Zeszyt 4 (December 2021)

Tom 43 (2021): Zeszyt 3 (September 2021)

Tom 43 (2021): Zeszyt 2 (June 2021)

Tom 43 (2021): Zeszyt s1 (December 2021)
Special Zeszyt: Underground Infrastructure of Urban Areas

Tom 43 (2021): Zeszyt 1 (April 2021)

Tom 42 (2020): Zeszyt 4 (December 2020)

Tom 42 (2020): Zeszyt 3 (September 2020)

Tom 42 (2020): Zeszyt 2 (June 2020)

Tom 42 (2020): Zeszyt 1 (April 2020)

Tom 41 (2019): Zeszyt 4 (December 2019)

Tom 41 (2019): Zeszyt 3 (September 2019)

Tom 41 (2019): Zeszyt 2 (June 2019)

Tom 41 (2019): Zeszyt 1 (April 2019)

Tom 40 (2018): Zeszyt 4 (December 2018)

Tom 40 (2018): Zeszyt 3 (November 2018)

Tom 40 (2018): Zeszyt 2 (October 2018)

Tom 40 (2018): Zeszyt 1 (July 2018)

Tom 39 (2017): Zeszyt 4 (December 2017)

Tom 39 (2017): Zeszyt 3 (September 2017)

Tom 39 (2017): Zeszyt 2 (June 2017)

Tom 39 (2017): Zeszyt 1 (March 2017)

Tom 38 (2016): Zeszyt 4 (December 2016)

Tom 38 (2016): Zeszyt 3 (September 2016)

Tom 38 (2016): Zeszyt 2 (June 2016)

Tom 38 (2016): Zeszyt 1 (March 2016)

Tom 37 (2015): Zeszyt 4 (December 2015)

Tom 37 (2015): Zeszyt 3 (September 2015)

Tom 37 (2015): Zeszyt 2 (June 2015)

Tom 37 (2015): Zeszyt 1 (March 2015)

Tom 36 (2014): Zeszyt 4 (December 2014)

Tom 36 (2014): Zeszyt 3 (September 2014)

Tom 36 (2014): Zeszyt 2 (June 2014)

Tom 36 (2014): Zeszyt 1 (March 2014)

Tom 35 (2013): Zeszyt 4 (December 2013)

Tom 35 (2013): Zeszyt 3 (September 2013)

Tom 35 (2013): Zeszyt 2 (June 2013)

Tom 35 (2013): Zeszyt 1 (March 2013)

Tom 34 (2012): Zeszyt 4 (December 2012)

Tom 34 (2012): Zeszyt 3 (September 2012)

Tom 34 (2012): Zeszyt 2 (June 2012)

Tom 34 (2012): Zeszyt 1 (March 2012)

Informacje o czasopiśmie
Format
Czasopismo
eISSN
2083-831X
Pierwsze wydanie
09 Nov 2012
Częstotliwość wydawania
4 razy w roku
Języki
Angielski

Wyszukiwanie

Tom 44 (2022): Zeszyt 1 (March 2022)

Informacje o czasopiśmie
Format
Czasopismo
eISSN
2083-831X
Pierwsze wydanie
09 Nov 2012
Częstotliwość wydawania
4 razy w roku
Języki
Angielski

Wyszukiwanie

7 Artykułów

Original Study

Otwarty dostęp

Contact interactions between soil and a corrugated metal sheet in soil-shell structures under construction

Data publikacji: 01 Oct 2021
Zakres stron: 1 - 12

Abstrakt

Abstract

During the construction of soil-shell objects, large deformations of the shell, which is made of corrugated metal sheet, occur. This enables geodetic techniques to be used when monitoring such objects. On this basis, displacements of selected points of the shell are determined, and it is then possible to obtain bending moments, as shown in this paper. Based on measurements using strain gauges in the circumferential band of the shell, internal forces in steel are estimated. The algorithm given in the paper enables the impact of soil on the shell in the examined objects to be analysed. The proposed method of analysing forces in the contact layer becomes especially useful when the static conditions of the model of a shell, which is considered as a bar submerged unilaterally in the soil medium, are met. The paper indicates the possibility of using both measuring techniques. Calculations include a smaller share of axial forces on the contact impact during the laying phase of the backfill. The paper provides examples of the analysis of built shells and record-breaking objects, with an assessment of the effectiveness of the proposed algorithm. Good mapping of contact forces, which were calculated on the basis of bending moments, was indicated even when there was not a dense grid of measuring points. An important advantage of the algorithm involves reduction of the circumferential band that is separated from the soil-shell system to the bar, which is an element resulting from the division of the structure into subsystems.

Słowa kluczowe

  • soil-steel structures
  • corrugated metal sheets
  • monitoring of the construction phase
  • strain gauge and geodetic measurements
Otwarty dostęp

An iterative algorithm for random upper bound kinematical analysis

Data publikacji: 10 Nov 2021
Zakres stron: 13 - 25

Abstrakt

Abstract

A new approach for stochastic upper bound kinematical analyses is described. The study proposes an iterative algorithm that uses the Vanmarcke spatial averaging and kinematical failure mechanisms. The iterative procedure ensures the consistency between failure geometry and covariance matrix, which influences the quality of the results. The proposed algorithm can be applied to bearing capacity evaluation or slope stability problems. The iterative algorithm is used in the study to analyse the three-dimensional undrained bearing capacity of shallow foundations and the bearing capacity of the foundation for two-layered soil, in both cases, the soil strength spatial variability is included. Moreover, the obtained results are compared with those provided by the algorithm, based on the constant covariance matrix. The study shows that both approaches provide similar results for a variety of foundation shapes and scale of fluctuation values. Therefore, the simplified algorithm can be used for purposes that require high computational efficiency and for practical applications. The achieved efficiency using a constant covariance matrix for one realisation of a three-dimensional bearing capacity problem that includes the soil strength spatial variability results in about 0.5 seconds for a standard notebook. The numerical example presented in the study indicates the importance of the iterative algorithm for further development of the failure mechanism application in probabilistic analyses. Moreover, because the iterative algorithm is based on the upper bound theorem, it could be utilised as a reference for other methods for spatially variable soil.

Słowa kluczowe

  • random bearing capacity
  • shallow foundation
  • scale of fluctuation
  • iterative algorithm
  • upper bound
  • spatial variability
Otwarty dostęp

Displacements of shell in soil-steel bridge subjected to moving load: determination using strain gauge measurements and numerical simulation

Data publikacji: 31 Mar 2022
Zakres stron: 26 - 37

Abstrakt

Abstract

This paper analyses displacements of a shell in a soil-steel bridge subjected to quasi-static moving loads. The considerations relate to a large span structure located in Ostróda, Poland. In particular, shell displacements during a loading cycle consisting of consecutive passages of a pair of trucks over the bridge are investigated. The results of a full-scale test, that is, the readings from a system of strain gauges arranged along the shell circumferential section, are the basis for determination of shell displacements. The proposed algorithm makes it possible to calculate any component of the displacement using just a simple model of the shell in the form of a linear elastic curvilinear beam. The approach uses real measurements, and thus, it yields results of displacements reflecting the actual mechanical behaviour of the entire composite structure including not only the shell, but also the backfill, the pavement, etc. The calculated state of displacement sets the basis for calibration of the numerical model. Finite element (FE) analyses include staged construction, that is, backfilling the shell by placing successive soil layers, as well as the loading test with the vehicles moving over the bridge. It is demonstrated that the ballasting of the shell during backfilling contributes to the improvement of the simulated behaviour of the object at the stage of operation, that is, when subjected to moving truck load. Thus, the calibration of the FE model is successfully carried out using the results of strain gauge measurements.

Słowa kluczowe

  • soil-steel structure
  • moving load
  • strain gauge
Otwarty dostęp

Numerical study on stress paths in grounds reinforced with long and short CFG piles during adjacent rigid retaining wall movement

Data publikacji: 31 Mar 2022
Zakres stron: 38 - 52

Abstrakt

Abstract

Ensuring the safety of existing structures is an important issue when planning and executing adjacent new foundation pit excavations. Hence, understanding the stress state conditions experienced by the soil element behind a retaining wall at a given location during different excavation stages has been a key observational modelling aspect of the performance of excavations. By establishing and carrying out sophisticated soil–structure interaction analyses, stress paths render clarity on soil deformation mechanism. On the other hand, column-type soft ground treatment has recently got exceeding attention and practical implementation. So, the soil stress–strain response to excavation-induced disturbances needs to be known as well. To this end, this paper discusses the stress change and redistribution phenomena in a treated ground based on 3D numerical analyses. The simulation was verified against results from a 1 g indoor experimental test conducted on composite foundation reinforced with long and short cement–fly ash–gravel (CFG) pile adjacent to a moving rigid retaining wall. It was observed that the stress path for each monitoring point in the shallow depth undergoes a process of stress unloading at various dropping amounts of principal stress components in a complex manner. The closer the soil element is to the wall, the more it experiences a change in principal stress components as the wall movement progresses; also, the induced stress disturbance weakens significantly as the observation point becomes farther away from the wall. Accordingly, the overall vertical load-sharing percentage of the upper soil reduces proportionally.

Słowa kluczowe

  • CFG pile
  • composite foundation
  • cushion
  • load-sharing ratio
  • retaining wall
  • excavation
Otwarty dostęp

Modern methods for monitoring water leakages in water networks

Data publikacji: 12 Mar 2022
Zakres stron: 53 - 65

Abstrakt

Abstract

The main idea of this article is to adopt the thesis that the main and, at the same time, the most effective (apart from proper maintenance and operation) element of the strategy of limiting water losses in water supply networks is continuous integrated monitoring of the network using the latest achievements of IT technologies, including GIS (Geographical Information System), GPS (Global Positioning System), GSM (The Global System for Mobile Communications) and software based on a cloud platform.

Considering the above, the paper highlights the problem of leakages against the background of water deficit in the world and proposes a classification of methods for detecting and estimating the size of leakages. On the basis of available literature sources, selected modern and, in the authors’ opinion, most interesting water loss monitoring systems enabling leak detection and estimation of the amount of wasted water are presented. Then, these methods are analysed, pointing to their strengths and weaknesses in terms of leak detection efficiency.

Słowa kluczowe

  • water supply networks
  • monitoring
  • water leakages
Otwarty dostęp

Evaluation of sand p–y curves by predicting both monopile lateral response and OWT natural frequency

Data publikacji: 10 Feb 2022
Zakres stron: 66 - 81

Abstrakt

Abstract

Extending the use of the p–y curves included in the regulation codes API and DNV to design large-diameter monopiles supporting offshore wind turbines (OWTs) was unsuccessful as it resulted in an inaccurate estimation of the monopile behavior. This had prompted many investigators to propose formulations to enhance the performances of Winkler model. In this paper, two case studies are considered. A case consisting of an OWT at Horns Rev (Denmark) supported by a monopile in a sandy soil was studied first. Taking the FEA using ABAQUS as reference, results of WILDOWER 1.0 (a Winkler computer code) using the recently proposed p–y curves giving design parameters were plotted and evaluated. In order to see the ability of proposed p–y curves to predict the monopile head movements, and consequently the first natural frequency (1st NF), a second case study consisting of a monopile supporting an OWT at North Hoyle (UK) was selected. The monopile head stiffness in terms of lateral, rocking, and cross-coupling stiffness coefficients, necessary for the 1st NF, were computed using both ABAQUS and WILDPOWER 1.0. Comparisons with the measured 1st NF showed that with the exception of one p–y model, none of other proposed Winkler methods is able to predict accurately this parameter.

Słowa kluczowe

  • FE analysis
  • p–y curves
  • Winkler model
  • cohesionless soils
  • monopiles
  • offshore wind turbines
  • natural frequency
  • soil–monopile stiffness
Otwarty dostęp

Importance of seismic wave frequency in FEM-based dynamic stress and displacement calculations of the earth slope

Data publikacji: 09 Feb 2022
Zakres stron: 82 - 96

Abstrakt

Abstract

Reliable assessment of earthen dams’ stability and tailing storage facilities widely used in the mining industry is challenging, particularly under seismic load conditions. In this paper, we propose to take into account the effect of the dominant frequency of seismic load on the stability assessment of tailing/earthen dams. The calculations are performed by finite element modelling (FEM) with the Mohr–Coulomb failure criteria. To separate the frequency content from other dynamic parameters describing the seismic wave, synthetic waveforms with identical amplitude and attenuation characteristics, but differing spectral characteristics have been used. The analysis has been performed for three different slope angles and two scenarios of seismic wave propagation. Consequently, the changes of total displacement and shear stresses depending on the frequencies have been determined and clearly show that lower frequencies cause higher stress levels and displacement. Finally, the response surface methodology has been applied to determine how different parameters affect the slope stability under dynamic load conditions. Overall, this study is a first step to improve the existing methods to assess slope stability when considering seismic load.

Słowa kluczowe

  • Slope stability
  • Numerical analysis
  • Seismic load
  • Frequency analysis
7 Artykułów

Original Study

Otwarty dostęp

Contact interactions between soil and a corrugated metal sheet in soil-shell structures under construction

Data publikacji: 01 Oct 2021
Zakres stron: 1 - 12

Abstrakt

Abstract

During the construction of soil-shell objects, large deformations of the shell, which is made of corrugated metal sheet, occur. This enables geodetic techniques to be used when monitoring such objects. On this basis, displacements of selected points of the shell are determined, and it is then possible to obtain bending moments, as shown in this paper. Based on measurements using strain gauges in the circumferential band of the shell, internal forces in steel are estimated. The algorithm given in the paper enables the impact of soil on the shell in the examined objects to be analysed. The proposed method of analysing forces in the contact layer becomes especially useful when the static conditions of the model of a shell, which is considered as a bar submerged unilaterally in the soil medium, are met. The paper indicates the possibility of using both measuring techniques. Calculations include a smaller share of axial forces on the contact impact during the laying phase of the backfill. The paper provides examples of the analysis of built shells and record-breaking objects, with an assessment of the effectiveness of the proposed algorithm. Good mapping of contact forces, which were calculated on the basis of bending moments, was indicated even when there was not a dense grid of measuring points. An important advantage of the algorithm involves reduction of the circumferential band that is separated from the soil-shell system to the bar, which is an element resulting from the division of the structure into subsystems.

Słowa kluczowe

  • soil-steel structures
  • corrugated metal sheets
  • monitoring of the construction phase
  • strain gauge and geodetic measurements
Otwarty dostęp

An iterative algorithm for random upper bound kinematical analysis

Data publikacji: 10 Nov 2021
Zakres stron: 13 - 25

Abstrakt

Abstract

A new approach for stochastic upper bound kinematical analyses is described. The study proposes an iterative algorithm that uses the Vanmarcke spatial averaging and kinematical failure mechanisms. The iterative procedure ensures the consistency between failure geometry and covariance matrix, which influences the quality of the results. The proposed algorithm can be applied to bearing capacity evaluation or slope stability problems. The iterative algorithm is used in the study to analyse the three-dimensional undrained bearing capacity of shallow foundations and the bearing capacity of the foundation for two-layered soil, in both cases, the soil strength spatial variability is included. Moreover, the obtained results are compared with those provided by the algorithm, based on the constant covariance matrix. The study shows that both approaches provide similar results for a variety of foundation shapes and scale of fluctuation values. Therefore, the simplified algorithm can be used for purposes that require high computational efficiency and for practical applications. The achieved efficiency using a constant covariance matrix for one realisation of a three-dimensional bearing capacity problem that includes the soil strength spatial variability results in about 0.5 seconds for a standard notebook. The numerical example presented in the study indicates the importance of the iterative algorithm for further development of the failure mechanism application in probabilistic analyses. Moreover, because the iterative algorithm is based on the upper bound theorem, it could be utilised as a reference for other methods for spatially variable soil.

Słowa kluczowe

  • random bearing capacity
  • shallow foundation
  • scale of fluctuation
  • iterative algorithm
  • upper bound
  • spatial variability
Otwarty dostęp

Displacements of shell in soil-steel bridge subjected to moving load: determination using strain gauge measurements and numerical simulation

Data publikacji: 31 Mar 2022
Zakres stron: 26 - 37

Abstrakt

Abstract

This paper analyses displacements of a shell in a soil-steel bridge subjected to quasi-static moving loads. The considerations relate to a large span structure located in Ostróda, Poland. In particular, shell displacements during a loading cycle consisting of consecutive passages of a pair of trucks over the bridge are investigated. The results of a full-scale test, that is, the readings from a system of strain gauges arranged along the shell circumferential section, are the basis for determination of shell displacements. The proposed algorithm makes it possible to calculate any component of the displacement using just a simple model of the shell in the form of a linear elastic curvilinear beam. The approach uses real measurements, and thus, it yields results of displacements reflecting the actual mechanical behaviour of the entire composite structure including not only the shell, but also the backfill, the pavement, etc. The calculated state of displacement sets the basis for calibration of the numerical model. Finite element (FE) analyses include staged construction, that is, backfilling the shell by placing successive soil layers, as well as the loading test with the vehicles moving over the bridge. It is demonstrated that the ballasting of the shell during backfilling contributes to the improvement of the simulated behaviour of the object at the stage of operation, that is, when subjected to moving truck load. Thus, the calibration of the FE model is successfully carried out using the results of strain gauge measurements.

Słowa kluczowe

  • soil-steel structure
  • moving load
  • strain gauge
Otwarty dostęp

Numerical study on stress paths in grounds reinforced with long and short CFG piles during adjacent rigid retaining wall movement

Data publikacji: 31 Mar 2022
Zakres stron: 38 - 52

Abstrakt

Abstract

Ensuring the safety of existing structures is an important issue when planning and executing adjacent new foundation pit excavations. Hence, understanding the stress state conditions experienced by the soil element behind a retaining wall at a given location during different excavation stages has been a key observational modelling aspect of the performance of excavations. By establishing and carrying out sophisticated soil–structure interaction analyses, stress paths render clarity on soil deformation mechanism. On the other hand, column-type soft ground treatment has recently got exceeding attention and practical implementation. So, the soil stress–strain response to excavation-induced disturbances needs to be known as well. To this end, this paper discusses the stress change and redistribution phenomena in a treated ground based on 3D numerical analyses. The simulation was verified against results from a 1 g indoor experimental test conducted on composite foundation reinforced with long and short cement–fly ash–gravel (CFG) pile adjacent to a moving rigid retaining wall. It was observed that the stress path for each monitoring point in the shallow depth undergoes a process of stress unloading at various dropping amounts of principal stress components in a complex manner. The closer the soil element is to the wall, the more it experiences a change in principal stress components as the wall movement progresses; also, the induced stress disturbance weakens significantly as the observation point becomes farther away from the wall. Accordingly, the overall vertical load-sharing percentage of the upper soil reduces proportionally.

Słowa kluczowe

  • CFG pile
  • composite foundation
  • cushion
  • load-sharing ratio
  • retaining wall
  • excavation
Otwarty dostęp

Modern methods for monitoring water leakages in water networks

Data publikacji: 12 Mar 2022
Zakres stron: 53 - 65

Abstrakt

Abstract

The main idea of this article is to adopt the thesis that the main and, at the same time, the most effective (apart from proper maintenance and operation) element of the strategy of limiting water losses in water supply networks is continuous integrated monitoring of the network using the latest achievements of IT technologies, including GIS (Geographical Information System), GPS (Global Positioning System), GSM (The Global System for Mobile Communications) and software based on a cloud platform.

Considering the above, the paper highlights the problem of leakages against the background of water deficit in the world and proposes a classification of methods for detecting and estimating the size of leakages. On the basis of available literature sources, selected modern and, in the authors’ opinion, most interesting water loss monitoring systems enabling leak detection and estimation of the amount of wasted water are presented. Then, these methods are analysed, pointing to their strengths and weaknesses in terms of leak detection efficiency.

Słowa kluczowe

  • water supply networks
  • monitoring
  • water leakages
Otwarty dostęp

Evaluation of sand p–y curves by predicting both monopile lateral response and OWT natural frequency

Data publikacji: 10 Feb 2022
Zakres stron: 66 - 81

Abstrakt

Abstract

Extending the use of the p–y curves included in the regulation codes API and DNV to design large-diameter monopiles supporting offshore wind turbines (OWTs) was unsuccessful as it resulted in an inaccurate estimation of the monopile behavior. This had prompted many investigators to propose formulations to enhance the performances of Winkler model. In this paper, two case studies are considered. A case consisting of an OWT at Horns Rev (Denmark) supported by a monopile in a sandy soil was studied first. Taking the FEA using ABAQUS as reference, results of WILDOWER 1.0 (a Winkler computer code) using the recently proposed p–y curves giving design parameters were plotted and evaluated. In order to see the ability of proposed p–y curves to predict the monopile head movements, and consequently the first natural frequency (1st NF), a second case study consisting of a monopile supporting an OWT at North Hoyle (UK) was selected. The monopile head stiffness in terms of lateral, rocking, and cross-coupling stiffness coefficients, necessary for the 1st NF, were computed using both ABAQUS and WILDPOWER 1.0. Comparisons with the measured 1st NF showed that with the exception of one p–y model, none of other proposed Winkler methods is able to predict accurately this parameter.

Słowa kluczowe

  • FE analysis
  • p–y curves
  • Winkler model
  • cohesionless soils
  • monopiles
  • offshore wind turbines
  • natural frequency
  • soil–monopile stiffness
Otwarty dostęp

Importance of seismic wave frequency in FEM-based dynamic stress and displacement calculations of the earth slope

Data publikacji: 09 Feb 2022
Zakres stron: 82 - 96

Abstrakt

Abstract

Reliable assessment of earthen dams’ stability and tailing storage facilities widely used in the mining industry is challenging, particularly under seismic load conditions. In this paper, we propose to take into account the effect of the dominant frequency of seismic load on the stability assessment of tailing/earthen dams. The calculations are performed by finite element modelling (FEM) with the Mohr–Coulomb failure criteria. To separate the frequency content from other dynamic parameters describing the seismic wave, synthetic waveforms with identical amplitude and attenuation characteristics, but differing spectral characteristics have been used. The analysis has been performed for three different slope angles and two scenarios of seismic wave propagation. Consequently, the changes of total displacement and shear stresses depending on the frequencies have been determined and clearly show that lower frequencies cause higher stress levels and displacement. Finally, the response surface methodology has been applied to determine how different parameters affect the slope stability under dynamic load conditions. Overall, this study is a first step to improve the existing methods to assess slope stability when considering seismic load.

Słowa kluczowe

  • Slope stability
  • Numerical analysis
  • Seismic load
  • Frequency analysis

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