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Special Edición: Underground Infrastructure of Urban Areas

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Detalles de la revista
Formato
Revista
eISSN
2083-831X
ISSN
0137-6365
Publicado por primera vez
09 Nov 2012
Periodo de publicación
4 veces al año
Idiomas
Inglés

Buscar

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

Detalles de la revista
Formato
Revista
eISSN
2083-831X
ISSN
0137-6365
Publicado por primera vez
09 Nov 2012
Periodo de publicación
4 veces al año
Idiomas
Inglés

Buscar

13 Artículos
Acceso abierto

Bearing Capacity of the Working Platform with Kinematic Method

Publicado en línea: 27 Mar 2015
Páginas: 3 - 8

Resumen

Abstract

Bearing capacity of the working platform for heavy tracks was analysed using Distinct Layout Optimization (DLO) method. The platform layer constructed from cohesionless soils is resting on weak cohesive subgrade. Different thickness of the platform, its effective angle of internal friction and undrained shear strength of the soft soil were taken into consideration. Kinematic method permits different failure mechanisms to be analyzed. Margin of safety for a given load and subsoil conditions was determined using two approaches: increasing the load or decreasing the shear strength up to failure. The results were compared with solution proposed in BRE recommendations.

Palabras clave

  • soft soil
  • undrained shear strength
  • limit state
  • failure mechanism
Acceso abierto

Specific Energy of Hard Coal Under Load

Publicado en línea: 27 Mar 2015
Páginas: 9 - 16

Resumen

Abstract

The article presents results of experimental tests of energy parameters of hard coals under loading, collected from research sites located within five main geologic structures of Upper Silesian Coal Basin (GZW) - Main Trough, Main Anticline, Bytom Trough, Rybnik Trough and Chwałowice Trough. Coals from12 mines were analysed, starting with seams of group 200, through groups 400, 500, 600 and, finally, seams of group 700. Coal of each of the groups of seams underwent uniaxial compression stress of the energy parameters, in a servo-controlled testing machine MTS-810NEW, for the full range of strain of the tested coal samples. Based on the tests the dependence of different types of specific energy of longitudinal strain of coals on the value of uniaxial compression strength was determined. The dependence of the value of dissipated energy and kinetic energy of coals on the uniaxial compression strength was described with a linear function, both for coals which due to their age belong to various bed sand for various lithotypes of coal. An increase in the value of dissipated energy and in kinetic energy was observed, which was correlated with an increase in uniaxial compression strength of coal. The share of dissipated energy is dominant in the total energy of strain. Share of recoverable energy in the total energy of strain is small, independent of the compression strength of coals and is at most a few per cent high. In coals of low strength and dominant share of dissipated energy, share of recoverable energy is the biggest among the tested coals. It was shown that following an increase in compression strength the share of recoverable energy decreases, while the share of dissipated energy in the total energy increases. Further studies of specific energy of longitudinal strain of rocks in the full-range strain will be the next step inperfecting methodology of research into natural rock burst susceptibility of Carboniferous rock mass and changes in the susceptibility resulting from mining activity.

Palabras clave

  • hard coal
  • specific energy of strain in coal
  • dissipated energy
  • kinetic energy
  • recoverable energy
Acceso abierto

Stress Drop as a Result of Splitting, Brittle and Transitional Faulting of Rock Samples in Uniaxial and Triaxial Compression Tests

Publicado en línea: 27 Mar 2015
Páginas: 17 - 23

Resumen

Abstract

Rock samples can behave brittle, transitional or ductile depending on test pressure, rate of loading and temperature. Axial stiffness and its changes, relative and absolute dilatancy, yield, and fracture thresholds, residual strength are strongly pressure dependent. In this paper the stress drop as an effect of rock sample strength loss due to failure was analyzed. Uniaxial and triaxial experiments on three types of rock were performed to investigate the stress drop phenomenon. The paper first introduces short background on rock behavior and parameters defining a failure process under uniaxial and triaxial loading conditions. Stress drop data collected with experiments are analyzed and its pressure dependence phenomenon is described. Two methods for evaluation of stress drop value are presented.

Palabras clave

  • Keywords laboratory investigations
  • stress drop
  • triaxial compression
Acceso abierto

What Were the Reasons for the Rapid Landslide Occurrence in “Piaseczno” Open Pit? – Analysis of the Landslide Process

Publicado en línea: 27 Mar 2015
Páginas: 25 - 35

Resumen

Abstract

Landslides are major natural hazards occurring in opencast mining. The problem of slope stability failure in the existing open pit mines as well as in those which are at a stage of technical closure is current issue in Poland and all over the world. This problem requires conducting in-depth and meaningful analysis which will identify the causes of processes characterized by a very rapid course and large extent.

The paper presents the analysis of the landslide causes, which took place on May 11, 2011 on the western slope of the internal dump in “Piaseczno” sulphur mine (at a stage of technical closure). It was the first native sulphur open pit mine in Poland in which the exploitation was carried out from 1958 untill 1971. Reclamation works have been ongoing since 2005. The aim of these works is to create water body which will be used for recreational purposes. During the reclamation works on the western slope of “Piaseczno” reservoir the landslide processes were activated. A detailed description of geology and preliminary analyses of landslide processes are given in [1]. The development of landslide took place in a very violent manner. Moreover, the occurrence of the landslide caused the movement of the reservoir shoreline by about 350 meters and created a bay with the area of approximately 6 hectares. Displacement of 600 000 m3 of soil masses under the water resulted in its level rising by 56 cm. The total volume of ground masses was over 1 million m3.

The analysis of the landslide process activation was carried out for two representative cross-sections of the internal dump. Numerical calculations were performed using the Limit Equilibrium Method (SLOPE/W GeoStudio) and the Finite Difference Method using the Shear Strength Reduction Method (FLAC Slope). They were aimed at determining the shape and extent of potential slip surface, which would correspond to the observed landslide. The purpose of the analysis, the results of which are presented in the article, was to define how the process proceeded and what factors contributed to its activation.

Palabras clave

  • landslide
  • open pit mine
  • slope stability analysis
  • numerical modelling
  • Limit Equilibrium Method (LEM)
  • Shear Strength Reduction Method (SSRM)
Acceso abierto

Numerical Estimation of the Pile Toe and Shaft Unit Resistances During the Installation Process in Sands

Publicado en línea: 27 Mar 2015
Páginas: 37 - 44

Resumen

Abstract

Numerical simulations of a pile jacking were carried out. A Coupled Eulerian-Lagrangian (CEL) formulation was used to treat with large deformation problems. An Abaqus, a commercial Finite Element Method software suit, was used as a computing environment. The Mohr-Coulomb constitutive model was applied and the Coulomb model of friction was used to describe pile-soil interaction. Calculations were made for three different pile diameters. Toe and shaft unit resistances versus depth for each pile were investigated and plotted. CPT-based solutions were compared with the results of numerical simulations.

Palabras clave

  • Coupled Eulerian-Lagrangian (CEL)
  • Abaqus
  • pile toe resistance
  • pile shaft resistance
Acceso abierto

Roadway Stability Evaluation on the Basis of Modern Monitoring of Displacement

Publicado en línea: 27 Mar 2015
Páginas: 45 - 52

Resumen

Abstract

The paper presents the application of a 3D laser measurement technology in a modern monitoring of roadways. The authors analyze the possibility of using a three-dimensional scanning measurement of longwall working dimensions. The measurement results are presented in the form of a cloud of points obtained from a 3D laser scanning. The paper also presents a comparison of the results obtained from the convergence of traditionally-made measurements with the measurements derived from the threedimensional scanning and discusses possible methods of comparing different point clouds.

Palabras clave

  • roadways
  • monitoring
  • convergence
Acceso abierto

The Three-Dimensional Imaging of Rock Wall Surface with the Use of Computer-Based Image Processing and Analysis

Publicado en línea: 27 Mar 2015
Páginas: 53 - 58

Resumen

Abstract

The paper presents two methods of digital mapping of rock walls in three dimensional space. The methods have been developed with the use of low-cost devices, which enable image acquisition, and processing methods based on digital image processing and analysis. Both methods are based on so-called shadow profilometry. One of those methods involved mapping the shape of the rock wall on casted mapped surface with analyzed laser lines. The second method was based on the analysis of projected set of bit planes. The planes were projected by computer projector. Both measurement methods have been tested in Miękinia porphyry quarry. The study involved rock wall measurements, which were repeated several times. The part of rock material was removed from the measured wall after each measurement. In order to verify the accuracy of the proposed methods of measurement, volume results obtained and based on digital methods were compared to the volume of removed rock material during measurement. Calculated results were characterized by small deviations which prove to be correct, and are a solid basis for further work on practical application of presented methods.

Palabras clave

  • rock surface
  • image analysis. 3D imaging
  • profilometry
Acceso abierto

Analysis of Embedded Retaining Wall Using the Subgrade Reaction Method

Publicado en línea: 27 Mar 2015
Páginas: 59 - 73

Resumen

Abstract

This paper analyzes the distribution of internal forces and displacements of embedded retaining wall in Quaternary deposits and Tertiary clays. Calculations have been based on the Subgrade Reaction Method (SRM) for two different types of earth pressure behind the wall (active, at-rest) in order to show the differences resulting from adopting the limit values. An algorithm for calculation of “cantilever wall” using the Mathematica program was proposed.

Palabras clave

  • earth pressure
  • internal forces
  • displacements
  • Subgrade Reaction Method
  • retaining wall
Acceso abierto

Microstructure Characterization by Means of X-ray Micro-CT and Nanoindentation Measurements

Publicado en línea: 27 Mar 2015
Páginas: 75 - 84

Resumen

Abstract

The aim of this paper is to present an example of the material microstructure characterization with the use of X-ray micro-CT and nanoindentation measurements. Firstly, the current scope of application of the aforementioned techniques is provided within different fields of science. Then, background of each of the methods is presented. The methodology of X-ray micro-CT is described with the emphasis on the Beer’s law formulation. In addition, the basics of the nanoindentation technique are outlined and major formulas for the hardness and Young’s modulus calculation are given. Finally, example results for a concrete sample are presented. The microstructure of the selected material is firstly characterized in terms of geometry using the results from the microtomograhy measurements, e.g., porosity and attenuation profiles, pore and aggregate size distribution, shape factor of pores, etc. Next, the results of the nanoindentation tests are provided, namely the hardness and Young’s modulus versus the height of the sample. The influence of the number of tests and statistical analysis on the final results is underlined.

Palabras clave

  • micro-CT
  • nanoindentation
  • microstructure
  • composite
Acceso abierto

New Instruments and Methods for Analysing the Coal-Methane System

Publicado en línea: 27 Mar 2015
Páginas: 85 - 91

Resumen

Abstract

The authors of the present paper designed and constructed a prototype of an instrument which enables fully automated determination of the desorbable methane content and effective diffusion coefficient in underground conditions. Due to microprocessor analysis of the recorded data and the application of the mathematical model of the diffusion process, it is possible to automatically determine the amount of methane whose release from a coal sample occurred before the sample was placed within a measuring instrument. It is also possible to carry out follow-up extrapolation of the recorded data so the time duration needed to determine reliable results can be reduced. The instrument was tested and optimized, and a number of copies sufficient for performing underground tests were constructed. The concept of the instrument represents a totally new approach to the observation of gas release from a coal sample. Instead of short-period measurements, virtually the whole process of methane release from coal is registered and analysed. This is possibly due to the use of a grain fraction lower than one mm which is presently applied for the sake of evaluating the methane- bearing capacity and desorption intensity.

Palabras clave

  • desorption
  • methane
  • carbon dioxide
  • coal
  • outburst
  • diffusion
Acceso abierto

Building a Numerical Model of the Filtration Flow in the Żelazny Most Flotation Tailings Disposal Lake

Publicado en línea: 27 Mar 2015
Páginas: 93 - 104

Resumen

Abstract

The paper presents results of numerical computations of the filtration flow of liquid contaminated wastes through the Żelazny Most flotation tailings disposal lake. Unlike the preceding papers [5]-[7], it takes the geological structure of the subsoil into account. A three-dimensional numerical model of the lake was created for computing purposes. Data on some of the effective model parameters were acquired from laboratory tests of the material taken from the lake site. The other data were taken from the literature for media of similar properties. The results of the computations carried out using the model can be a basis for future numerical analyses aimed at determining the consolidation of the flotation tailings disposal lake and its subsoil, and the stability of the lake.

Palabras clave

  • filtration flow
  • three-dimensional numerical model
  • flotation wastes
  • tailings disposal lake
Acceso abierto

Relation Between Filtration and Soil Consolidation Theories

Publicado en línea: 27 Mar 2015
Páginas: 105 - 114

Resumen

Abstract

This paper presents a different, than commonly used, form of equations describing the filtration of a viscous compressible fluid through a porous medium in isothermal conditions. This mathematical model is compared with the liquid flow equations used in the theory of consolidation. It is shown that the current commonly used filtration model representation significantly differs from the filtration process representation in Biot’s and Terzaghi’s soil consolidation models, which has a bearing on the use of the methods of determining the filtration coefficient on the basis of oedometer test results. The present analysis of the filtration theory equations should help interpret effective parameters of the non-steady filtration model. Moreover, equations for the flow of a gas through a porous medium and an interpretation of the filtration model effective parameters in this case are presented.

Palabras clave

  • filtration
  • seepage
  • soil consolidation
  • underground water
Acceso abierto

Rock Strength Anisotropy in High Stress Conditions: A Case Study for Application to Shaft Stability Assessments

Publicado en línea: 27 Mar 2015
Páginas: 115 - 125

Resumen

Abstract

Although rock strength anisotropy is a well-known phenomenon in rock mechanics, its impact on geotechnical design is often ignored or underestimated. This paper explores the concept of anisotropy in a high stress environment using an improved unified constitutive model (IUCM), which can account for more complex failure mechanisms. The IUCM is used to better understand the typical responses of anisotropic rocks to underground mining. This study applies the IUCM to a proposed rock shaft located in high stress/anisotropic conditions. Results suggest that the effect of rock strength anisotropy must be taken into consideration when assessing the rock mass response to mining in high stress and anisotropic rock conditions.

Palabras clave

  • anisotropy
  • high stress
  • numerical modeling
  • constitutive model
13 Artículos
Acceso abierto

Bearing Capacity of the Working Platform with Kinematic Method

Publicado en línea: 27 Mar 2015
Páginas: 3 - 8

Resumen

Abstract

Bearing capacity of the working platform for heavy tracks was analysed using Distinct Layout Optimization (DLO) method. The platform layer constructed from cohesionless soils is resting on weak cohesive subgrade. Different thickness of the platform, its effective angle of internal friction and undrained shear strength of the soft soil were taken into consideration. Kinematic method permits different failure mechanisms to be analyzed. Margin of safety for a given load and subsoil conditions was determined using two approaches: increasing the load or decreasing the shear strength up to failure. The results were compared with solution proposed in BRE recommendations.

Palabras clave

  • soft soil
  • undrained shear strength
  • limit state
  • failure mechanism
Acceso abierto

Specific Energy of Hard Coal Under Load

Publicado en línea: 27 Mar 2015
Páginas: 9 - 16

Resumen

Abstract

The article presents results of experimental tests of energy parameters of hard coals under loading, collected from research sites located within five main geologic structures of Upper Silesian Coal Basin (GZW) - Main Trough, Main Anticline, Bytom Trough, Rybnik Trough and Chwałowice Trough. Coals from12 mines were analysed, starting with seams of group 200, through groups 400, 500, 600 and, finally, seams of group 700. Coal of each of the groups of seams underwent uniaxial compression stress of the energy parameters, in a servo-controlled testing machine MTS-810NEW, for the full range of strain of the tested coal samples. Based on the tests the dependence of different types of specific energy of longitudinal strain of coals on the value of uniaxial compression strength was determined. The dependence of the value of dissipated energy and kinetic energy of coals on the uniaxial compression strength was described with a linear function, both for coals which due to their age belong to various bed sand for various lithotypes of coal. An increase in the value of dissipated energy and in kinetic energy was observed, which was correlated with an increase in uniaxial compression strength of coal. The share of dissipated energy is dominant in the total energy of strain. Share of recoverable energy in the total energy of strain is small, independent of the compression strength of coals and is at most a few per cent high. In coals of low strength and dominant share of dissipated energy, share of recoverable energy is the biggest among the tested coals. It was shown that following an increase in compression strength the share of recoverable energy decreases, while the share of dissipated energy in the total energy increases. Further studies of specific energy of longitudinal strain of rocks in the full-range strain will be the next step inperfecting methodology of research into natural rock burst susceptibility of Carboniferous rock mass and changes in the susceptibility resulting from mining activity.

Palabras clave

  • hard coal
  • specific energy of strain in coal
  • dissipated energy
  • kinetic energy
  • recoverable energy
Acceso abierto

Stress Drop as a Result of Splitting, Brittle and Transitional Faulting of Rock Samples in Uniaxial and Triaxial Compression Tests

Publicado en línea: 27 Mar 2015
Páginas: 17 - 23

Resumen

Abstract

Rock samples can behave brittle, transitional or ductile depending on test pressure, rate of loading and temperature. Axial stiffness and its changes, relative and absolute dilatancy, yield, and fracture thresholds, residual strength are strongly pressure dependent. In this paper the stress drop as an effect of rock sample strength loss due to failure was analyzed. Uniaxial and triaxial experiments on three types of rock were performed to investigate the stress drop phenomenon. The paper first introduces short background on rock behavior and parameters defining a failure process under uniaxial and triaxial loading conditions. Stress drop data collected with experiments are analyzed and its pressure dependence phenomenon is described. Two methods for evaluation of stress drop value are presented.

Palabras clave

  • Keywords laboratory investigations
  • stress drop
  • triaxial compression
Acceso abierto

What Were the Reasons for the Rapid Landslide Occurrence in “Piaseczno” Open Pit? – Analysis of the Landslide Process

Publicado en línea: 27 Mar 2015
Páginas: 25 - 35

Resumen

Abstract

Landslides are major natural hazards occurring in opencast mining. The problem of slope stability failure in the existing open pit mines as well as in those which are at a stage of technical closure is current issue in Poland and all over the world. This problem requires conducting in-depth and meaningful analysis which will identify the causes of processes characterized by a very rapid course and large extent.

The paper presents the analysis of the landslide causes, which took place on May 11, 2011 on the western slope of the internal dump in “Piaseczno” sulphur mine (at a stage of technical closure). It was the first native sulphur open pit mine in Poland in which the exploitation was carried out from 1958 untill 1971. Reclamation works have been ongoing since 2005. The aim of these works is to create water body which will be used for recreational purposes. During the reclamation works on the western slope of “Piaseczno” reservoir the landslide processes were activated. A detailed description of geology and preliminary analyses of landslide processes are given in [1]. The development of landslide took place in a very violent manner. Moreover, the occurrence of the landslide caused the movement of the reservoir shoreline by about 350 meters and created a bay with the area of approximately 6 hectares. Displacement of 600 000 m3 of soil masses under the water resulted in its level rising by 56 cm. The total volume of ground masses was over 1 million m3.

The analysis of the landslide process activation was carried out for two representative cross-sections of the internal dump. Numerical calculations were performed using the Limit Equilibrium Method (SLOPE/W GeoStudio) and the Finite Difference Method using the Shear Strength Reduction Method (FLAC Slope). They were aimed at determining the shape and extent of potential slip surface, which would correspond to the observed landslide. The purpose of the analysis, the results of which are presented in the article, was to define how the process proceeded and what factors contributed to its activation.

Palabras clave

  • landslide
  • open pit mine
  • slope stability analysis
  • numerical modelling
  • Limit Equilibrium Method (LEM)
  • Shear Strength Reduction Method (SSRM)
Acceso abierto

Numerical Estimation of the Pile Toe and Shaft Unit Resistances During the Installation Process in Sands

Publicado en línea: 27 Mar 2015
Páginas: 37 - 44

Resumen

Abstract

Numerical simulations of a pile jacking were carried out. A Coupled Eulerian-Lagrangian (CEL) formulation was used to treat with large deformation problems. An Abaqus, a commercial Finite Element Method software suit, was used as a computing environment. The Mohr-Coulomb constitutive model was applied and the Coulomb model of friction was used to describe pile-soil interaction. Calculations were made for three different pile diameters. Toe and shaft unit resistances versus depth for each pile were investigated and plotted. CPT-based solutions were compared with the results of numerical simulations.

Palabras clave

  • Coupled Eulerian-Lagrangian (CEL)
  • Abaqus
  • pile toe resistance
  • pile shaft resistance
Acceso abierto

Roadway Stability Evaluation on the Basis of Modern Monitoring of Displacement

Publicado en línea: 27 Mar 2015
Páginas: 45 - 52

Resumen

Abstract

The paper presents the application of a 3D laser measurement technology in a modern monitoring of roadways. The authors analyze the possibility of using a three-dimensional scanning measurement of longwall working dimensions. The measurement results are presented in the form of a cloud of points obtained from a 3D laser scanning. The paper also presents a comparison of the results obtained from the convergence of traditionally-made measurements with the measurements derived from the threedimensional scanning and discusses possible methods of comparing different point clouds.

Palabras clave

  • roadways
  • monitoring
  • convergence
Acceso abierto

The Three-Dimensional Imaging of Rock Wall Surface with the Use of Computer-Based Image Processing and Analysis

Publicado en línea: 27 Mar 2015
Páginas: 53 - 58

Resumen

Abstract

The paper presents two methods of digital mapping of rock walls in three dimensional space. The methods have been developed with the use of low-cost devices, which enable image acquisition, and processing methods based on digital image processing and analysis. Both methods are based on so-called shadow profilometry. One of those methods involved mapping the shape of the rock wall on casted mapped surface with analyzed laser lines. The second method was based on the analysis of projected set of bit planes. The planes were projected by computer projector. Both measurement methods have been tested in Miękinia porphyry quarry. The study involved rock wall measurements, which were repeated several times. The part of rock material was removed from the measured wall after each measurement. In order to verify the accuracy of the proposed methods of measurement, volume results obtained and based on digital methods were compared to the volume of removed rock material during measurement. Calculated results were characterized by small deviations which prove to be correct, and are a solid basis for further work on practical application of presented methods.

Palabras clave

  • rock surface
  • image analysis. 3D imaging
  • profilometry
Acceso abierto

Analysis of Embedded Retaining Wall Using the Subgrade Reaction Method

Publicado en línea: 27 Mar 2015
Páginas: 59 - 73

Resumen

Abstract

This paper analyzes the distribution of internal forces and displacements of embedded retaining wall in Quaternary deposits and Tertiary clays. Calculations have been based on the Subgrade Reaction Method (SRM) for two different types of earth pressure behind the wall (active, at-rest) in order to show the differences resulting from adopting the limit values. An algorithm for calculation of “cantilever wall” using the Mathematica program was proposed.

Palabras clave

  • earth pressure
  • internal forces
  • displacements
  • Subgrade Reaction Method
  • retaining wall
Acceso abierto

Microstructure Characterization by Means of X-ray Micro-CT and Nanoindentation Measurements

Publicado en línea: 27 Mar 2015
Páginas: 75 - 84

Resumen

Abstract

The aim of this paper is to present an example of the material microstructure characterization with the use of X-ray micro-CT and nanoindentation measurements. Firstly, the current scope of application of the aforementioned techniques is provided within different fields of science. Then, background of each of the methods is presented. The methodology of X-ray micro-CT is described with the emphasis on the Beer’s law formulation. In addition, the basics of the nanoindentation technique are outlined and major formulas for the hardness and Young’s modulus calculation are given. Finally, example results for a concrete sample are presented. The microstructure of the selected material is firstly characterized in terms of geometry using the results from the microtomograhy measurements, e.g., porosity and attenuation profiles, pore and aggregate size distribution, shape factor of pores, etc. Next, the results of the nanoindentation tests are provided, namely the hardness and Young’s modulus versus the height of the sample. The influence of the number of tests and statistical analysis on the final results is underlined.

Palabras clave

  • micro-CT
  • nanoindentation
  • microstructure
  • composite
Acceso abierto

New Instruments and Methods for Analysing the Coal-Methane System

Publicado en línea: 27 Mar 2015
Páginas: 85 - 91

Resumen

Abstract

The authors of the present paper designed and constructed a prototype of an instrument which enables fully automated determination of the desorbable methane content and effective diffusion coefficient in underground conditions. Due to microprocessor analysis of the recorded data and the application of the mathematical model of the diffusion process, it is possible to automatically determine the amount of methane whose release from a coal sample occurred before the sample was placed within a measuring instrument. It is also possible to carry out follow-up extrapolation of the recorded data so the time duration needed to determine reliable results can be reduced. The instrument was tested and optimized, and a number of copies sufficient for performing underground tests were constructed. The concept of the instrument represents a totally new approach to the observation of gas release from a coal sample. Instead of short-period measurements, virtually the whole process of methane release from coal is registered and analysed. This is possibly due to the use of a grain fraction lower than one mm which is presently applied for the sake of evaluating the methane- bearing capacity and desorption intensity.

Palabras clave

  • desorption
  • methane
  • carbon dioxide
  • coal
  • outburst
  • diffusion
Acceso abierto

Building a Numerical Model of the Filtration Flow in the Żelazny Most Flotation Tailings Disposal Lake

Publicado en línea: 27 Mar 2015
Páginas: 93 - 104

Resumen

Abstract

The paper presents results of numerical computations of the filtration flow of liquid contaminated wastes through the Żelazny Most flotation tailings disposal lake. Unlike the preceding papers [5]-[7], it takes the geological structure of the subsoil into account. A three-dimensional numerical model of the lake was created for computing purposes. Data on some of the effective model parameters were acquired from laboratory tests of the material taken from the lake site. The other data were taken from the literature for media of similar properties. The results of the computations carried out using the model can be a basis for future numerical analyses aimed at determining the consolidation of the flotation tailings disposal lake and its subsoil, and the stability of the lake.

Palabras clave

  • filtration flow
  • three-dimensional numerical model
  • flotation wastes
  • tailings disposal lake
Acceso abierto

Relation Between Filtration and Soil Consolidation Theories

Publicado en línea: 27 Mar 2015
Páginas: 105 - 114

Resumen

Abstract

This paper presents a different, than commonly used, form of equations describing the filtration of a viscous compressible fluid through a porous medium in isothermal conditions. This mathematical model is compared with the liquid flow equations used in the theory of consolidation. It is shown that the current commonly used filtration model representation significantly differs from the filtration process representation in Biot’s and Terzaghi’s soil consolidation models, which has a bearing on the use of the methods of determining the filtration coefficient on the basis of oedometer test results. The present analysis of the filtration theory equations should help interpret effective parameters of the non-steady filtration model. Moreover, equations for the flow of a gas through a porous medium and an interpretation of the filtration model effective parameters in this case are presented.

Palabras clave

  • filtration
  • seepage
  • soil consolidation
  • underground water
Acceso abierto

Rock Strength Anisotropy in High Stress Conditions: A Case Study for Application to Shaft Stability Assessments

Publicado en línea: 27 Mar 2015
Páginas: 115 - 125

Resumen

Abstract

Although rock strength anisotropy is a well-known phenomenon in rock mechanics, its impact on geotechnical design is often ignored or underestimated. This paper explores the concept of anisotropy in a high stress environment using an improved unified constitutive model (IUCM), which can account for more complex failure mechanisms. The IUCM is used to better understand the typical responses of anisotropic rocks to underground mining. This study applies the IUCM to a proposed rock shaft located in high stress/anisotropic conditions. Results suggest that the effect of rock strength anisotropy must be taken into consideration when assessing the rock mass response to mining in high stress and anisotropic rock conditions.

Palabras clave

  • anisotropy
  • high stress
  • numerical modeling
  • constitutive model

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