Magazine et Edition

AHEAD OF PRINT

Volume 44 (2022): Edition 3 (September 2022)

Volume 44 (2022): Edition 2 (June 2022)

Volume 44 (2022): Edition 1 (March 2022)

Volume 43 (2021): Edition 4 (December 2021)

Volume 43 (2021): Edition 3 (September 2021)

Volume 43 (2021): Edition 2 (June 2021)

Volume 43 (2021): Edition s1 (December 2021)
Special Edition: Underground Infrastructure of Urban Areas

Volume 43 (2021): Edition 1 (April 2021)

Volume 42 (2020): Edition 4 (December 2020)

Volume 42 (2020): Edition 3 (September 2020)

Volume 42 (2020): Edition 2 (June 2020)

Volume 42 (2020): Edition 1 (April 2020)

Volume 41 (2019): Edition 4 (December 2019)

Volume 41 (2019): Edition 3 (September 2019)

Volume 41 (2019): Edition 2 (June 2019)

Volume 41 (2019): Edition 1 (April 2019)

Volume 40 (2018): Edition 4 (December 2018)

Volume 40 (2018): Edition 3 (November 2018)

Volume 40 (2018): Edition 2 (October 2018)

Volume 40 (2018): Edition 1 (July 2018)

Volume 39 (2017): Edition 4 (December 2017)

Volume 39 (2017): Edition 3 (September 2017)

Volume 39 (2017): Edition 2 (June 2017)

Volume 39 (2017): Edition 1 (March 2017)

Volume 38 (2016): Edition 4 (December 2016)

Volume 38 (2016): Edition 3 (September 2016)

Volume 38 (2016): Edition 2 (June 2016)

Volume 38 (2016): Edition 1 (March 2016)

Volume 37 (2015): Edition 4 (December 2015)

Volume 37 (2015): Edition 3 (September 2015)

Volume 37 (2015): Edition 2 (June 2015)

Volume 37 (2015): Edition 1 (March 2015)

Volume 36 (2014): Edition 4 (December 2014)

Volume 36 (2014): Edition 3 (September 2014)

Volume 36 (2014): Edition 2 (June 2014)

Volume 36 (2014): Edition 1 (March 2014)

Volume 35 (2013): Edition 4 (December 2013)

Volume 35 (2013): Edition 3 (September 2013)

Volume 35 (2013): Edition 2 (June 2013)

Volume 35 (2013): Edition 1 (March 2013)

Volume 34 (2012): Edition 4 (December 2012)

Volume 34 (2012): Edition 3 (September 2012)

Volume 34 (2012): Edition 2 (June 2012)

Volume 34 (2012): Edition 1 (March 2012)

Détails du magazine
Format
Magazine
eISSN
2083-831X
Première publication
09 Nov 2012
Période de publication
4 fois par an
Langues
Anglais

Chercher

Volume 37 (2015): Edition 3 (September 2015)

Détails du magazine
Format
Magazine
eISSN
2083-831X
Première publication
09 Nov 2012
Période de publication
4 fois par an
Langues
Anglais

Chercher

12 Articles
Accès libre

Ultrasonic Waves and Strength Reduction Indexes for the Assessment of the Advancement of Deterioration Processes in Travertines from Pamukkale and Hierapolis (Turkey)

Publié en ligne: 17 Nov 2015
Pages: 3 - 9

Résumé

Abstract

In constructions, the usefulness of modern technical diagnostics of stone as a raw material requires predicting the effects of long-term environmental impact of its qualities and geomechanical properties. The paper presents geomechanical research enabling presentation of the factors for strength loss of the stone and forecasting the rate of development of destructive phenomena on the stone structure on a long-time basis. As research material Turkish travertines were selected from the Denizli-Kaklık Basin (Pamukkale and Hierapolis quarries), which have been commonly used for centuries in global architecture. The rock material was subjected to testing of the impact of various environmental factors, as well as European standards recommended by the author of the research program. Their resistance to the crystallization of salts from aqueous solutions and the effects of SO2, as well as the effect of frost and high temperatures are presented. The studies allowed establishing the following quantitative indicators: the ultrasonic waves index (IVp) and the strength reduction index (IRc). Reflections on the assessment of deterioration effects indicate that the most active factors decreasing travertine resistance in the aging process include frost and sulphur dioxide (SO2). Their negative influence is particularly intense when the stone material is already strongly weathered.

Mots clés

  • travertine
  • deterioration
  • geomechanical properties
  • ultrasonic diagnosis
  • strength
Accès libre

Ground Penetrating Radar Investigations of Landslides: A Case Study in a Landslide in Radziszów

Publié en ligne: 17 Nov 2015
Pages: 11 - 18

Résumé

Abstract

The article presents the results of research of the activated landslide in Radziszów in 2010. The study focused on the evaluation of engineering geology conditions, preceded by geophysical surveys. It mainly focused on the GPR method using the IDS georadar equipped with antennas in the frequency range of 100 MHz. Antenna selection was based on archival research which showed that the depth of occurrence of clays, where the roof can be a potential slip surface, ranges between 3-10 m below the surface.

GPR method applied allowed the course of the potential slip surface to be determined and the results obtained significantly correlated with the results of engineering geology tests carried out.

Mots clés

  • geophysical methods - GPR
  • geohazards
  • landslide
Accès libre

An Analysis of Excavation Support Safety Based on Experimental Studies

Publié en ligne: 17 Nov 2015
Pages: 19 - 29

Résumé

Abstract

The article presents the results of inclinometric measurements and numerical analyses of soldier-pile wall displacements. The excavation under investigation was made in cohesive soils. The measurements were conducted at points located at the edge of the cantilever excavation support system. The displacements of the excavation support observed over the period of three years demonstrated the pattern of steady growth over the first two months, followed by a gradual levelling out to a final plateau. The numerical analyses were conducted based on 3D FEM models. The numerical analysis of the problem comprise calculations of the global structural safety factor depending on the displacement of the chosen points in the lagging and conducted by means of the φ/c reduction procedure. The adopted graphical method of safety estimation is very conservative in the sense that it recognizes stability loss quite early, when one could further load the medium or weaken it by further strength reduction. The values of the Msf factor are relatively high. This is caused by the fact that the structure was designed for excavation twice as deep. Nevertheless, the structure is treated as a temporary one.

Mots clés

  • soldier-pile wall
  • inclinometer measurements
  • φ/c reduction procedure
Accès libre

Evaluation of Bearing Capacity of Strip Footing Using Random Layers Concept

Publié en ligne: 17 Nov 2015
Pages: 31 - 39

Résumé

Abstract

The paper deals with evaluation of bearing capacity of strip foundation on random purely cohesive soil. The approach proposed combines random field theory in the form of random layers with classical limit analysis and Monte Carlo simulation. For given realization of random the bearing capacity of strip footing is evaluated by employing the kinematic approach of yield design theory. The results in the form of histograms for both bearing capacity of footing as well as optimal depth of failure mechanism are obtained for different thickness of random layers. For zero and infinite thickness of random layer the values of depth of failure mechanism as well as bearing capacity assessment are derived in a closed form. Finally based on a sequence of Monte Carlo simulations the bearing capacity of strip footing corresponding to a certain probability of failure is estimated. While the mean value of the foundation bearing capacity increases with the thickness of the random layers, the ultimate load corresponding to a certain probability of failure appears to be a decreasing function of random layers thickness.

Mots clés

  • random field theory
  • reliability
  • bearing capacity
  • random layers concept
  • kinematic approach
Accès libre

Recognition of Anhydrite Intercalated Salt Deposit from Seismic Dataset Distorted by Noise

Publié en ligne: 17 Nov 2015
Pages: 41 - 48

Résumé

Abstract

Acoustic inversion is useful to extract information from seismic data. Inhomogeneities of salt deposits should be predicted before the decision of underground storage location is made. The work concerns the possibility of detecting anhydrite intercalation in the rock salt from seismic dataset. The resolution strongly depends on signal to noise ratio. The synthetic pseudoacoustic impedance sections are generated for efficiency test of predictive and minimum entropy deconvolution process, when random noise distorts the seismic traces.

Mots clés

  • underground storage
  • acoustic impedance
  • salt deposit
  • inhomogeneity detection
  • noise
Accès libre

Pile Model Tests Using Strain Gauge Technology

Publié en ligne: 17 Nov 2015
Pages: 49 - 52

Résumé

Abstract

Ordinary pile bearing capacity tests are usually carried out to determine the relationship between load and displacement of pile head. The measurement system required in such tests consists of force transducer and three or four displacement gauges. The whole system is installed at the pile head above the ground level. This approach, however, does not give us complete information about the pile-soil interaction. We can only determine the total bearing capacity of the pile, without the knowledge of its distribution into the shaft and base resistances. Much more information can be obtained by carrying out a test of instrumented pile equipped with a system for measuring the distribution of axial force along its core. In the case of pile model tests the use of such measurement is difficult due to small scale of the model.

To find a suitable solution for axial force measurement, which could be applied to small scale model piles, we had to take into account the following requirements:

- a linear and stable relationship between measured and physical values,

- the force measurement accuracy of about 0.1 kN,

- the range of measured forces up to 30 kN,

- resistance of measuring gauges against aggressive counteraction of concrete mortar and against moisture,

- insensitivity to pile bending,

- economical factor.

These requirements can be fulfilled by strain gauge sensors if an appropriate methodology is used for test preparation (Hoffmann [1]). In this paper, we focus on some aspects of the application of strain gauge sensors for model pile tests. The efficiency of the method is proved on the examples of static load tests carried out on SDP model piles acting as single piles and in a group.

Mots clés

  • screw displacement piles
  • CFA piles
  • deep foundation
  • model tests
  • group of piles
Accès libre

Experimentally Validated Nonlinear Analysis of Bridge Plate Girders with Deformations

Publié en ligne: 17 Nov 2015
Pages: 53 - 61

Résumé

Abstract

Comprehensive methodology of numerical nonlinear analysis of the consecutive phases in the structural behaviour of bridge plate girders with deformations is presented. The analysis concerns all stages of structure loading until failure and especially determination of the ultimate shear load capacity. Verification and validation of the numerical procedures proposed is based on comparison of the calculated results with effects of experimental laboratory shear capacity tests of plate girders carried out at the University of Ljubljana.

Mots clés

  • FEM analysis
  • experimental tests
  • bridge plate girders
  • deformations
  • load capacity
Accès libre

Analysis of Harmonic Vibration of Cable-Stayed Footbridge under the Influence of Changes of the Cables Tension

Publié en ligne: 17 Nov 2015
Pages: 63 - 71

Résumé

Abstract

The paper presents numerical analysis of harmonically excited vibration of a cable-stayed footbridge caused by a load function simulating crouching (squats) while changing the static tension in chosen cables. The intentional synchronized motion (e.g., squats) of a single person or group of persons on the footbridge with a frequency close to the natural frequency of the structure may lead to the resonant vibrations with large amplitudes. The appropriate tension changes in some cables cause detuning of resonance on account of stiffness changes of structures and hence detuning in the natural frequency that is close to the excitation frequency. The research was carried out on a 3D computer model of a real structure - a cable-stayed steel footbridge in Leśnica, a quarter of Wrocław, Poland, with the help of standard computer software based on FEM COSMOS/M System.

Mots clés

  • cable-stayed footbridge
  • FEM model
  • harmonic vibration
  • vibration reduction
Accès libre

On Unsaturated Soil Mechanics – Personal Views on Current Research

Publié en ligne: 17 Nov 2015
Pages: 73 - 84

Résumé

Abstract

This paper presents the authors’ personal views on current research being conducted by various research groups around the world in the broad area of mechanics of unsaturated geomaterials in general and soils in particular. The topic is of interest to a wide spectrum of scientists and engineers working in diverse areas such as geology and geophysics, powder technology, agricultural, petroleum, chemical, geotechnical, civil, environmental and nuclear engineering. Even if we restrict ourselves to civil, geotechnical and environmental engineering, it is noted that a plethora of hypotheses as well as a number of empirical and semi-empirical relations have been introduced for describing the mechanics of unsaturated porous media. However, many of these proposed advances as well as methods of testing may lack sound theoretical basis.

Mots clés

  • unsaturated soil
  • suction
  • microstructure of saturation
  • constitutive relation
Accès libre

Influence of Structural Features and Fracture Processes on Surface Roughness: A Case Study from the Krosno Sandstones of the Górka–Mucharz Quarry (Little Beskids, Southern Poland)

Publié en ligne: 17 Nov 2015
Pages: 85 - 93

Résumé

Abstract

The paper presents the results of analysis of surface roughness parameters in the Krosno Sandstones of Mucharz, southern Poland. It was aimed at determining whether these parameters are influenced by structural features (mainly the laminar distribution of mineral components and directional distribution of non-isometric grains) and fracture processes. The tests applied in the analysis enabled us to determine and describe the primary statistical parameters used in the quantitative description of surface roughness, as well as specify the usefulness of contact profilometry as a method of visualizing spatial differentiation of fracture processes in rocks. These aims were achieved by selecting a model material (Krosno Sandstones from the Górka-Mucharz Quarry) and an appropriate research methodology. The schedule of laboratory analyses included: identification analyses connected with non-destructive ultrasonic tests, aimed at the preliminary determination of rock anisotropy, strength point load tests (cleaved surfaces were obtained due to destruction of rock samples), microscopic analysis (observation of thin sections in order to determine the mechanism of inducing fracture processes) and a test method of measuring surface roughness (two- and three-dimensional diagrams, topographic and contour maps, and statistical parameters of surface roughness). The highest values of roughness indicators were achieved for surfaces formed under the influence of intragranular fracture processes (cracks propagating directly through grains). This is related to the structural features of the Krosno Sandstones (distribution of lamination and bedding).

Mots clés

  • anisotropy
  • rock cracking
  • fracture processes
  • flysch
  • geomechanics
  • Krosno Sandstones
  • surface roughness
Accès libre

Technical Note: Example of the Application of Jet Grouting to the Neutralisation of Geotechnical Hazard in Shaft Structures

Publié en ligne: 17 Nov 2015
Pages: 95 - 99

Résumé

Abstract

The article presents a geotechnical hazard neutralisation technology for shaft structures. The diagnosis of problems with uncontrolled subsidence of the ventilation duct provided by the authors enabled the development of a schedule of works required for the protection and reinforcement of foundation soil in the shaft area. The technology of protection works was selected after the analysis of the technical condition of shaft structures as well as hydrological and geomechanical conditions. Due to the closeness of the shaft lining, it was necessary to form grout columns using jet grouting and low-pressure grouting technologies. The article presents the issues related to the selected technology and its application to the neutralisation of the emergent geotechnical hazard. The method of performance of recommended works was also described together with their impact on the technical condition of structures discussed as well as their functionality and usage.

Mots clés

  • jet grouting
  • shaft
  • mining construction
  • structure diagnostics
Accès libre

Technical Note: Outlays on Construction of Airport Runways with Prestressed and Dowelled Pavements

Publié en ligne: 17 Nov 2015
Pages: 101 - 111

Résumé

Abstract

For two variants of runways with abrasive concrete pavements in the prestressed and dowelled technologies, analyses have been presented regarding labour, materials, use of machinery, and financial outlays, together with the necessary technological-organisational analyses and assessment of work execution cycles, by the example of construction of a runway at the Katowice Airport.

Mots clés

  • dowelled runway
  • prestressed concrete
  • technology and organization of construction
12 Articles
Accès libre

Ultrasonic Waves and Strength Reduction Indexes for the Assessment of the Advancement of Deterioration Processes in Travertines from Pamukkale and Hierapolis (Turkey)

Publié en ligne: 17 Nov 2015
Pages: 3 - 9

Résumé

Abstract

In constructions, the usefulness of modern technical diagnostics of stone as a raw material requires predicting the effects of long-term environmental impact of its qualities and geomechanical properties. The paper presents geomechanical research enabling presentation of the factors for strength loss of the stone and forecasting the rate of development of destructive phenomena on the stone structure on a long-time basis. As research material Turkish travertines were selected from the Denizli-Kaklık Basin (Pamukkale and Hierapolis quarries), which have been commonly used for centuries in global architecture. The rock material was subjected to testing of the impact of various environmental factors, as well as European standards recommended by the author of the research program. Their resistance to the crystallization of salts from aqueous solutions and the effects of SO2, as well as the effect of frost and high temperatures are presented. The studies allowed establishing the following quantitative indicators: the ultrasonic waves index (IVp) and the strength reduction index (IRc). Reflections on the assessment of deterioration effects indicate that the most active factors decreasing travertine resistance in the aging process include frost and sulphur dioxide (SO2). Their negative influence is particularly intense when the stone material is already strongly weathered.

Mots clés

  • travertine
  • deterioration
  • geomechanical properties
  • ultrasonic diagnosis
  • strength
Accès libre

Ground Penetrating Radar Investigations of Landslides: A Case Study in a Landslide in Radziszów

Publié en ligne: 17 Nov 2015
Pages: 11 - 18

Résumé

Abstract

The article presents the results of research of the activated landslide in Radziszów in 2010. The study focused on the evaluation of engineering geology conditions, preceded by geophysical surveys. It mainly focused on the GPR method using the IDS georadar equipped with antennas in the frequency range of 100 MHz. Antenna selection was based on archival research which showed that the depth of occurrence of clays, where the roof can be a potential slip surface, ranges between 3-10 m below the surface.

GPR method applied allowed the course of the potential slip surface to be determined and the results obtained significantly correlated with the results of engineering geology tests carried out.

Mots clés

  • geophysical methods - GPR
  • geohazards
  • landslide
Accès libre

An Analysis of Excavation Support Safety Based on Experimental Studies

Publié en ligne: 17 Nov 2015
Pages: 19 - 29

Résumé

Abstract

The article presents the results of inclinometric measurements and numerical analyses of soldier-pile wall displacements. The excavation under investigation was made in cohesive soils. The measurements were conducted at points located at the edge of the cantilever excavation support system. The displacements of the excavation support observed over the period of three years demonstrated the pattern of steady growth over the first two months, followed by a gradual levelling out to a final plateau. The numerical analyses were conducted based on 3D FEM models. The numerical analysis of the problem comprise calculations of the global structural safety factor depending on the displacement of the chosen points in the lagging and conducted by means of the φ/c reduction procedure. The adopted graphical method of safety estimation is very conservative in the sense that it recognizes stability loss quite early, when one could further load the medium or weaken it by further strength reduction. The values of the Msf factor are relatively high. This is caused by the fact that the structure was designed for excavation twice as deep. Nevertheless, the structure is treated as a temporary one.

Mots clés

  • soldier-pile wall
  • inclinometer measurements
  • φ/c reduction procedure
Accès libre

Evaluation of Bearing Capacity of Strip Footing Using Random Layers Concept

Publié en ligne: 17 Nov 2015
Pages: 31 - 39

Résumé

Abstract

The paper deals with evaluation of bearing capacity of strip foundation on random purely cohesive soil. The approach proposed combines random field theory in the form of random layers with classical limit analysis and Monte Carlo simulation. For given realization of random the bearing capacity of strip footing is evaluated by employing the kinematic approach of yield design theory. The results in the form of histograms for both bearing capacity of footing as well as optimal depth of failure mechanism are obtained for different thickness of random layers. For zero and infinite thickness of random layer the values of depth of failure mechanism as well as bearing capacity assessment are derived in a closed form. Finally based on a sequence of Monte Carlo simulations the bearing capacity of strip footing corresponding to a certain probability of failure is estimated. While the mean value of the foundation bearing capacity increases with the thickness of the random layers, the ultimate load corresponding to a certain probability of failure appears to be a decreasing function of random layers thickness.

Mots clés

  • random field theory
  • reliability
  • bearing capacity
  • random layers concept
  • kinematic approach
Accès libre

Recognition of Anhydrite Intercalated Salt Deposit from Seismic Dataset Distorted by Noise

Publié en ligne: 17 Nov 2015
Pages: 41 - 48

Résumé

Abstract

Acoustic inversion is useful to extract information from seismic data. Inhomogeneities of salt deposits should be predicted before the decision of underground storage location is made. The work concerns the possibility of detecting anhydrite intercalation in the rock salt from seismic dataset. The resolution strongly depends on signal to noise ratio. The synthetic pseudoacoustic impedance sections are generated for efficiency test of predictive and minimum entropy deconvolution process, when random noise distorts the seismic traces.

Mots clés

  • underground storage
  • acoustic impedance
  • salt deposit
  • inhomogeneity detection
  • noise
Accès libre

Pile Model Tests Using Strain Gauge Technology

Publié en ligne: 17 Nov 2015
Pages: 49 - 52

Résumé

Abstract

Ordinary pile bearing capacity tests are usually carried out to determine the relationship between load and displacement of pile head. The measurement system required in such tests consists of force transducer and three or four displacement gauges. The whole system is installed at the pile head above the ground level. This approach, however, does not give us complete information about the pile-soil interaction. We can only determine the total bearing capacity of the pile, without the knowledge of its distribution into the shaft and base resistances. Much more information can be obtained by carrying out a test of instrumented pile equipped with a system for measuring the distribution of axial force along its core. In the case of pile model tests the use of such measurement is difficult due to small scale of the model.

To find a suitable solution for axial force measurement, which could be applied to small scale model piles, we had to take into account the following requirements:

- a linear and stable relationship between measured and physical values,

- the force measurement accuracy of about 0.1 kN,

- the range of measured forces up to 30 kN,

- resistance of measuring gauges against aggressive counteraction of concrete mortar and against moisture,

- insensitivity to pile bending,

- economical factor.

These requirements can be fulfilled by strain gauge sensors if an appropriate methodology is used for test preparation (Hoffmann [1]). In this paper, we focus on some aspects of the application of strain gauge sensors for model pile tests. The efficiency of the method is proved on the examples of static load tests carried out on SDP model piles acting as single piles and in a group.

Mots clés

  • screw displacement piles
  • CFA piles
  • deep foundation
  • model tests
  • group of piles
Accès libre

Experimentally Validated Nonlinear Analysis of Bridge Plate Girders with Deformations

Publié en ligne: 17 Nov 2015
Pages: 53 - 61

Résumé

Abstract

Comprehensive methodology of numerical nonlinear analysis of the consecutive phases in the structural behaviour of bridge plate girders with deformations is presented. The analysis concerns all stages of structure loading until failure and especially determination of the ultimate shear load capacity. Verification and validation of the numerical procedures proposed is based on comparison of the calculated results with effects of experimental laboratory shear capacity tests of plate girders carried out at the University of Ljubljana.

Mots clés

  • FEM analysis
  • experimental tests
  • bridge plate girders
  • deformations
  • load capacity
Accès libre

Analysis of Harmonic Vibration of Cable-Stayed Footbridge under the Influence of Changes of the Cables Tension

Publié en ligne: 17 Nov 2015
Pages: 63 - 71

Résumé

Abstract

The paper presents numerical analysis of harmonically excited vibration of a cable-stayed footbridge caused by a load function simulating crouching (squats) while changing the static tension in chosen cables. The intentional synchronized motion (e.g., squats) of a single person or group of persons on the footbridge with a frequency close to the natural frequency of the structure may lead to the resonant vibrations with large amplitudes. The appropriate tension changes in some cables cause detuning of resonance on account of stiffness changes of structures and hence detuning in the natural frequency that is close to the excitation frequency. The research was carried out on a 3D computer model of a real structure - a cable-stayed steel footbridge in Leśnica, a quarter of Wrocław, Poland, with the help of standard computer software based on FEM COSMOS/M System.

Mots clés

  • cable-stayed footbridge
  • FEM model
  • harmonic vibration
  • vibration reduction
Accès libre

On Unsaturated Soil Mechanics – Personal Views on Current Research

Publié en ligne: 17 Nov 2015
Pages: 73 - 84

Résumé

Abstract

This paper presents the authors’ personal views on current research being conducted by various research groups around the world in the broad area of mechanics of unsaturated geomaterials in general and soils in particular. The topic is of interest to a wide spectrum of scientists and engineers working in diverse areas such as geology and geophysics, powder technology, agricultural, petroleum, chemical, geotechnical, civil, environmental and nuclear engineering. Even if we restrict ourselves to civil, geotechnical and environmental engineering, it is noted that a plethora of hypotheses as well as a number of empirical and semi-empirical relations have been introduced for describing the mechanics of unsaturated porous media. However, many of these proposed advances as well as methods of testing may lack sound theoretical basis.

Mots clés

  • unsaturated soil
  • suction
  • microstructure of saturation
  • constitutive relation
Accès libre

Influence of Structural Features and Fracture Processes on Surface Roughness: A Case Study from the Krosno Sandstones of the Górka–Mucharz Quarry (Little Beskids, Southern Poland)

Publié en ligne: 17 Nov 2015
Pages: 85 - 93

Résumé

Abstract

The paper presents the results of analysis of surface roughness parameters in the Krosno Sandstones of Mucharz, southern Poland. It was aimed at determining whether these parameters are influenced by structural features (mainly the laminar distribution of mineral components and directional distribution of non-isometric grains) and fracture processes. The tests applied in the analysis enabled us to determine and describe the primary statistical parameters used in the quantitative description of surface roughness, as well as specify the usefulness of contact profilometry as a method of visualizing spatial differentiation of fracture processes in rocks. These aims were achieved by selecting a model material (Krosno Sandstones from the Górka-Mucharz Quarry) and an appropriate research methodology. The schedule of laboratory analyses included: identification analyses connected with non-destructive ultrasonic tests, aimed at the preliminary determination of rock anisotropy, strength point load tests (cleaved surfaces were obtained due to destruction of rock samples), microscopic analysis (observation of thin sections in order to determine the mechanism of inducing fracture processes) and a test method of measuring surface roughness (two- and three-dimensional diagrams, topographic and contour maps, and statistical parameters of surface roughness). The highest values of roughness indicators were achieved for surfaces formed under the influence of intragranular fracture processes (cracks propagating directly through grains). This is related to the structural features of the Krosno Sandstones (distribution of lamination and bedding).

Mots clés

  • anisotropy
  • rock cracking
  • fracture processes
  • flysch
  • geomechanics
  • Krosno Sandstones
  • surface roughness
Accès libre

Technical Note: Example of the Application of Jet Grouting to the Neutralisation of Geotechnical Hazard in Shaft Structures

Publié en ligne: 17 Nov 2015
Pages: 95 - 99

Résumé

Abstract

The article presents a geotechnical hazard neutralisation technology for shaft structures. The diagnosis of problems with uncontrolled subsidence of the ventilation duct provided by the authors enabled the development of a schedule of works required for the protection and reinforcement of foundation soil in the shaft area. The technology of protection works was selected after the analysis of the technical condition of shaft structures as well as hydrological and geomechanical conditions. Due to the closeness of the shaft lining, it was necessary to form grout columns using jet grouting and low-pressure grouting technologies. The article presents the issues related to the selected technology and its application to the neutralisation of the emergent geotechnical hazard. The method of performance of recommended works was also described together with their impact on the technical condition of structures discussed as well as their functionality and usage.

Mots clés

  • jet grouting
  • shaft
  • mining construction
  • structure diagnostics
Accès libre

Technical Note: Outlays on Construction of Airport Runways with Prestressed and Dowelled Pavements

Publié en ligne: 17 Nov 2015
Pages: 101 - 111

Résumé

Abstract

For two variants of runways with abrasive concrete pavements in the prestressed and dowelled technologies, analyses have been presented regarding labour, materials, use of machinery, and financial outlays, together with the necessary technological-organisational analyses and assessment of work execution cycles, by the example of construction of a runway at the Katowice Airport.

Mots clés

  • dowelled runway
  • prestressed concrete
  • technology and organization of construction

Planifiez votre conférence à distance avec Sciendo