The document summarizes laboratory experiments conducted to measure local scour (erosion of sediment) around bridge piers arranged in different configurations. Equations were developed through statistical analysis to predict scour depth based on experimental data for single piers and pier groups. A new equation is proposed for predicting scour in pile groups. The effectiveness of slots in piers for minimizing scour is also examined.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online
This document describes an extension of the SRICOS method for predicting scour depth at bridge piers. The extended method, called E-SRICOS, accounts for variable flow velocities over time (velocity-time histories) and multilayer soil stratigraphy. It accumulates the effects of different velocities and sequences through soil layers to predict scour depth. The document outlines the E-SRICOS algorithms and procedures. It also presents a simplified version, S-SRICOS, and compares predictions of both methods to measurements at eight bridge sites in Texas.
This study examined solute transport in unsaturated soil using two sampling techniques - solution samplers and soil excavation. Bromide, nitrate, and chloride tracers were applied to a field plot instrumented with solution samplers at depths of 0.25m and 0.65m. At the end of the experiment, the entire plot was destructively sampled to a depth of 2m. Solution samplers recovered 63-83% of tracer mass while excavation recovered 96-105%. Solution samplers underestimated mean solute velocity compared to excavation. Both techniques showed increasing dispersion with travel time, indicating a scale-dependent dispersion process. Tracer depth profiles were accurately described by a stochastic transport
AVO (Amplitude variation with offset) analysis can distinguish between lithology changes and fluid changes that cause bright spots on seismic sections. The variation in seismic reflection amplitude with source-geophone distance depends on velocity, density, and Poisson's ratio contrast, with a large Poisson's ratio change producing increased amplitude with offset when gas is present as a pore fluid. AVO principles indicate that Poisson's ratio decreases when gas replaces brine in reservoirs, causing reflection coefficient and amplitude to become more negative with increasing offset distance. AVO analysis aims to identify pore fluids.
Experimental Study of Local Scour around Single Spur Dike in an Open ChannelIRJET Journal
The document presents the results of an experimental study on local scour around single spur dikes in an open channel. Laboratory experiments were conducted with three different spur dike models having varying opening ratios (0.82, 0.85, 0.88) placed at three angles (60°, 80°, 90°) relative to flow direction. Scour patterns were analyzed for different flow conditions defined by Froude number (0.63, 0.96, 1.29). Results show that maximum scour depth occurs upstream of spur dikes and sediment deposition occurs downstream. All relative scour parameters (depth, length, width) increase with higher Froude number and decrease with smaller opening ratios and angles closer to 60°. Relationships
Field and Theoretical Analysis of Accelerated Consolidation Using Vertical Dr...inventionjournals
Mumbai is the region consisting of soft compressible marine clay deposits. There are several construction problems on such soils and thus ground improvement is need to be carried out. Vertical drains is generally preferred technique as accelerated settlement is achieved during the construction phase itself if planned accordingly. The concept of vertical drains is based on the theory of three dimensional consolidation as described by Terzaghi (1943). Based on this concept, a consolidation programme is developed and an attempt is made to determine the field to laboratory coefficient of vertical consolidation ratio by Taylor’s Square Root of Time Method and Casagrande’s Logarithm of Time Fitting Method for this region. Based on this, the rate of consolidation and time required for consolidation in the field can be determined knowing the consolidation parameters. Equations are developed by using output of the programme and it is explained.
1. The study compared concentrations of nitrate-nitrogen (N-NO3) and phosphate-phosphorus (P-PO4) in subsurface drainage water from cropland under free drainage and controlled drainage management.
2. N-NO3 and P-PO4 concentrations in drainage water were not significantly different between controlled and free drainage systems over three years.
3. N-NO3 and P-PO4 concentrations did increase significantly in all plots following field-applied fertilizer, indicating fertilizer as a source of these nutrients in drainage water.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online
This document describes an extension of the SRICOS method for predicting scour depth at bridge piers. The extended method, called E-SRICOS, accounts for variable flow velocities over time (velocity-time histories) and multilayer soil stratigraphy. It accumulates the effects of different velocities and sequences through soil layers to predict scour depth. The document outlines the E-SRICOS algorithms and procedures. It also presents a simplified version, S-SRICOS, and compares predictions of both methods to measurements at eight bridge sites in Texas.
This study examined solute transport in unsaturated soil using two sampling techniques - solution samplers and soil excavation. Bromide, nitrate, and chloride tracers were applied to a field plot instrumented with solution samplers at depths of 0.25m and 0.65m. At the end of the experiment, the entire plot was destructively sampled to a depth of 2m. Solution samplers recovered 63-83% of tracer mass while excavation recovered 96-105%. Solution samplers underestimated mean solute velocity compared to excavation. Both techniques showed increasing dispersion with travel time, indicating a scale-dependent dispersion process. Tracer depth profiles were accurately described by a stochastic transport
AVO (Amplitude variation with offset) analysis can distinguish between lithology changes and fluid changes that cause bright spots on seismic sections. The variation in seismic reflection amplitude with source-geophone distance depends on velocity, density, and Poisson's ratio contrast, with a large Poisson's ratio change producing increased amplitude with offset when gas is present as a pore fluid. AVO principles indicate that Poisson's ratio decreases when gas replaces brine in reservoirs, causing reflection coefficient and amplitude to become more negative with increasing offset distance. AVO analysis aims to identify pore fluids.
Experimental Study of Local Scour around Single Spur Dike in an Open ChannelIRJET Journal
The document presents the results of an experimental study on local scour around single spur dikes in an open channel. Laboratory experiments were conducted with three different spur dike models having varying opening ratios (0.82, 0.85, 0.88) placed at three angles (60°, 80°, 90°) relative to flow direction. Scour patterns were analyzed for different flow conditions defined by Froude number (0.63, 0.96, 1.29). Results show that maximum scour depth occurs upstream of spur dikes and sediment deposition occurs downstream. All relative scour parameters (depth, length, width) increase with higher Froude number and decrease with smaller opening ratios and angles closer to 60°. Relationships
Field and Theoretical Analysis of Accelerated Consolidation Using Vertical Dr...inventionjournals
Mumbai is the region consisting of soft compressible marine clay deposits. There are several construction problems on such soils and thus ground improvement is need to be carried out. Vertical drains is generally preferred technique as accelerated settlement is achieved during the construction phase itself if planned accordingly. The concept of vertical drains is based on the theory of three dimensional consolidation as described by Terzaghi (1943). Based on this concept, a consolidation programme is developed and an attempt is made to determine the field to laboratory coefficient of vertical consolidation ratio by Taylor’s Square Root of Time Method and Casagrande’s Logarithm of Time Fitting Method for this region. Based on this, the rate of consolidation and time required for consolidation in the field can be determined knowing the consolidation parameters. Equations are developed by using output of the programme and it is explained.
1. The study compared concentrations of nitrate-nitrogen (N-NO3) and phosphate-phosphorus (P-PO4) in subsurface drainage water from cropland under free drainage and controlled drainage management.
2. N-NO3 and P-PO4 concentrations in drainage water were not significantly different between controlled and free drainage systems over three years.
3. N-NO3 and P-PO4 concentrations did increase significantly in all plots following field-applied fertilizer, indicating fertilizer as a source of these nutrients in drainage water.
This document describes a Runge-Kutta Discontinuous Galerkin method for approximating the shallow water equations. The method introduces two techniques: 1) a flux modification technique to derive a well-balanced scheme that preserves steady states at rest with variable bathymetry, and 2) a slope modification technique to properly handle flooding and drying of water. Numerical results are presented to illustrate the performance of the proposed scheme.
Open Pit Stability Analysis. Cobre Las Cruces is an open pit mine that extracts copper sulphides from the same volcano-sedimentary Paleozoic deposit as the mines of Rio Tinto.
The exploitation is in essence an open pit measuring 1600 m long x 900 m wide x 250 m deep.
FIELD AND THEORETICAL ANALYSIS OF ACCELERATED CONSOLIDATION USING VERTICAL DR...P singh
Mumbai is the region consisting of soft compressible marine clay deposits. There are several construction problems on such soils and thus ground improvement is need to be carried out. Vertical drains is generally preferred technique as accelerated settlement is achieved during the construction phase itself if planned accordingly. The concept of vertical drains is based on the theory of three dimensional consolidation as described by Terzaghi (1943). Based on this concept, a consolidation programme is developed and an attempt is made to determine the field to laboratory coefficient of vertical consolidation ratio by Taylor’s Square Root of Time Method and Casagrande’s Logarithm of Time Fitting Method for this region by considering the case study of Bhandup Lagoon Works Embankment. Based on this ratio, the rate of consolidation and time required for consolidation in the field can be determined knowing the consolidation parameters. Equations are developed by using output of the programme and it is explained.
Reservoir Geophysics : Brian Russell Lecture 2Ali Osman Öncel
This document discusses Amplitude Variation with Offset (AVO) techniques and impedance inversion methods. It covers the basics of AVO modeling using the Zoeppritz, Aki-Richards, and Fatti equations. The key methods are described, including intercept-gradient analysis and modeling AVO classes. Examples are provided to illustrate modeling reflections from wet versus gas sands and comparing the different AVO modeling approaches.
Advances in Rock Physics Modelling and Improved Estimation of CO2 Saturation, Giorgos Papageorgiou - Geophysical Modelling for CO2 Storage, Leeds, 3 November 2015
1) The document describes a study applying poststack acoustic impedance inversion to characterize subsalt reservoirs using 3D seismic data from the Walker Ridge protraction area in the Gulf of Mexico.
2) Inversion of a depth-migrated seismic volume was able to derive relative acoustic impedance, which was then used with a background model to estimate absolute acoustic impedance.
3) Comparison of inverted acoustic impedance to well logs showed good agreement, indicating the potential for quantitative seismic analysis of subsalt reservoirs despite challenges of low frequencies and complex salt geometry.
The document discusses using an automated dynamic cone penetrometer (ADCP) to characterize subgrade soil resilient modulus (MR) through correlation with ADCP index (DCPI). Twelve subgrade sections with varying soil types were tested with ADCP and falling weight deflectometer before and after pavement construction. Undisturbed soil samples were also extracted and tested in the laboratory for MR. Regression models were developed to correlate MR with DCPI for fine-grained and coarse-grained soils, accounting for other physical properties. Results suggest ADCP can reliably estimate MR and detect changes in subgrade stiffness from pavement loading.
This document discusses using geostatistical analysis to understand soil moisture dynamics at a small catchment scale. Daily soil moisture data from 111 sensors over 3.5 years was analyzed. Variogram analysis showed limitations in accurately estimating the nugget variance without paired sensors. Kriging interpolation was performed, but results were limited by inaccurate variograms that were sometimes unbounded with high sill and range values. The analysis demonstrated the importance of accurately estimating the nugget variance for robust geostatistical modeling of soil moisture dynamics.
This document discusses modeling groyne placement on river bends based on sedimentation analysis using numerical simulation with the finite difference method. The goal is to determine optimal groyne placement by considering sediment accumulation volumes in groyne fields.
The study plans to simulate 450 cases combining various groyne positions, lengths, flow velocities, bend radii, and suspended sediment concentrations. Conservation equations for mass and momentum will be used to develop the mathematical model. Validation and verification processes will evaluate the agreement between experimental data and model predictions.
Regression analysis of simulation results will determine suitability coefficients to obtain relationships between parameters like Froude number and groyne length, providing guidance on best distances between groynes. The numerical model aims
Pore scale dynamics and the interpretation of flow processes - Martin Blunt, Imperial College London, at UKCCSRC specialist meeting Flow and Transport for CO2 Storage, 29-30 October 2015
This document summarizes a study that uses fractal geometry to predict permeability from other rock properties like porosity. It presents a new approach based on fractal models of pore space. The study derives relationships between permeability and pore radius distributions or porosity for different rock types using data from 640 sandstone samples. These relationships take the form of power laws with parameters calibrated for each rock type. The predicted permeabilities compare well to measured values. This approach provides a petrophysically justified way to estimate permeability from commonly available well log properties like porosity.
CO2-Driven Enhanced Gas Recovery and Storage in Depleted Shale Reservoir- A N...Steve Wittrig
1) The document discusses using numerical simulation to analyze CO2-enhanced gas recovery and storage in depleted shale gas reservoirs. It aims to maximize methane production while delaying CO2 breakthrough and maximizing CO2 storage.
2) Different injection scenarios are defined based on modifications to well patterns, reservoir characteristics, fracture properties, sorption parameters, and operational constraints. The scenarios vary the spacing between injection and production wells.
3) The best injection practice will be proposed based on analyzing different scenarios to enhance methane recovery and minimize CO2 production from the reservoir while storing more CO2.
This document summarizes research analyzing groundwater flow processes in fractured chalk rock in the United Kingdom under both pumped and ambient conditions. Key findings include:
1) Under pumped conditions, flow was concentrated along four discrete fractures with good agreement between different flow measurement methods.
2) Under ambient conditions, the system was more complicated with apparent cross-flow occurring over the upper 29 meters complicating measurement interpretations.
3) Estimates of aquifer transmissivity from different analysis methods ranged from 2,049 to over 4,388 square meters per day, with discrepancies attributed to non-linear head losses and some flows bypassing the upper 29 meter region during pumping.
1. The document defines key rock physics terms including density, porosity, saturation, velocity, impedance, Poisson's ratio, and reflection coefficients. Equations are provided for calculating these values from measured properties.
2. Methods of modeling reflection seismograms are described including normal reflection, reflection at an angle using Zoeppritz equations, AVO analysis, and impedance inversion.
3. Concepts of stress, strain, elasticity, elastic moduli, and their relationships to velocity are covered. The differences between static and dynamic moduli are also discussed.
1) The document discusses assessing uncertainty in time-lapse seismic response due to geomechanical deformation.
2) It presents a multi-physics solution that couples fluid flow and geomechanics modeling to better understand stress changes over time.
3) An example application to the Valhall oil field models pore pressure changes and resulting geomechanical effects, partitioning the domain for parallel modeling of the overburden, reservoir, and underburden.
This study used elastic impedance inversion and pre-stack attribute analysis on 3D seismic data with limited well control to identify productive zones in an offshore Iranian reservoir. Poisson dampening factor and Lame parameters extracted from pre-stack simultaneous inversion effectively delineated hydrocarbon-bearing areas, validated by crossplots of elastic impedance volumes. The attribute analysis results at well locations were generalized to the full seismic volume since the reservoir was considered laterally homogeneous.
This document summarizes the analysis of petrophysical data from two wells in the Upper Spraberry Formation to develop a rock-fluid model. Six distinct rock types were identified based on unique pore geometry, mineral composition, and fluid flow characteristics. Laboratory analysis of core plugs using nitrogen, helium, and mercury injection characterized porosity, permeability, pore size distribution, and wettability of each rock type. Clean sandy rocks generally had higher porosity and permeability than shaly or dolostone units. Integration of petrophysical data with log responses and core descriptions allowed differentiation of reservoir-quality from lower-quality rock intervals in the formation.
1. AVO inversion and processing of seismic data from the Penguin Field was challenging due to noise in the data and lack of clear AVO trends.
2. Pre-stack diagnostics identified issues like residual moveout and multiples that were addressed through additional processing steps.
3. Post-stack diagnostics on near, mid, and far stacks helped assess whether the data obeyed expected AVO behavior needed for inversion.
4. Inversion results for properties like Vshale, porosity, and net-to-gross ratio showed improved detail compared to original reservoir models.
INGENUITY IN SOIL REINFORCEMENT METHODS AGAINST SCOUR FAILUREEdison Mugoya
GEOTECHNICAL ENGINEERING: INGENUITY IN SOIL
REINFORCEMENT METHODS AGAINST SCOUR FAILURE
is a study in geotechnical engineering regarding the scour failure at bridge abutments. its a methodology used to decrease it's effects and prolong the life cycle of bridge piers
Retrofitting the well foundation of a railway bridge subjected to scourSushil Dhungana
This document discusses retrofitting techniques for strengthening the well foundation of a railway bridge subjected to scour. It proposes two retrofitting methods: 1) Installing piles around the well foundation, but finds this would not fully transfer loads or relieve pressure. 2) Creating a shallow foundation around the well to partly transfer vertical loads, all moments, and protect against scour in the top 2.5-3m. Analysis shows bearing pressure is within capacity even for increased modern loading standards. The revised approach of a reinforced concrete ring foundation is suggested to strengthen the existing well foundation against failure due to bending stresses or scour.
This document describes a Runge-Kutta Discontinuous Galerkin method for approximating the shallow water equations. The method introduces two techniques: 1) a flux modification technique to derive a well-balanced scheme that preserves steady states at rest with variable bathymetry, and 2) a slope modification technique to properly handle flooding and drying of water. Numerical results are presented to illustrate the performance of the proposed scheme.
Open Pit Stability Analysis. Cobre Las Cruces is an open pit mine that extracts copper sulphides from the same volcano-sedimentary Paleozoic deposit as the mines of Rio Tinto.
The exploitation is in essence an open pit measuring 1600 m long x 900 m wide x 250 m deep.
FIELD AND THEORETICAL ANALYSIS OF ACCELERATED CONSOLIDATION USING VERTICAL DR...P singh
Mumbai is the region consisting of soft compressible marine clay deposits. There are several construction problems on such soils and thus ground improvement is need to be carried out. Vertical drains is generally preferred technique as accelerated settlement is achieved during the construction phase itself if planned accordingly. The concept of vertical drains is based on the theory of three dimensional consolidation as described by Terzaghi (1943). Based on this concept, a consolidation programme is developed and an attempt is made to determine the field to laboratory coefficient of vertical consolidation ratio by Taylor’s Square Root of Time Method and Casagrande’s Logarithm of Time Fitting Method for this region by considering the case study of Bhandup Lagoon Works Embankment. Based on this ratio, the rate of consolidation and time required for consolidation in the field can be determined knowing the consolidation parameters. Equations are developed by using output of the programme and it is explained.
Reservoir Geophysics : Brian Russell Lecture 2Ali Osman Öncel
This document discusses Amplitude Variation with Offset (AVO) techniques and impedance inversion methods. It covers the basics of AVO modeling using the Zoeppritz, Aki-Richards, and Fatti equations. The key methods are described, including intercept-gradient analysis and modeling AVO classes. Examples are provided to illustrate modeling reflections from wet versus gas sands and comparing the different AVO modeling approaches.
Advances in Rock Physics Modelling and Improved Estimation of CO2 Saturation, Giorgos Papageorgiou - Geophysical Modelling for CO2 Storage, Leeds, 3 November 2015
1) The document describes a study applying poststack acoustic impedance inversion to characterize subsalt reservoirs using 3D seismic data from the Walker Ridge protraction area in the Gulf of Mexico.
2) Inversion of a depth-migrated seismic volume was able to derive relative acoustic impedance, which was then used with a background model to estimate absolute acoustic impedance.
3) Comparison of inverted acoustic impedance to well logs showed good agreement, indicating the potential for quantitative seismic analysis of subsalt reservoirs despite challenges of low frequencies and complex salt geometry.
The document discusses using an automated dynamic cone penetrometer (ADCP) to characterize subgrade soil resilient modulus (MR) through correlation with ADCP index (DCPI). Twelve subgrade sections with varying soil types were tested with ADCP and falling weight deflectometer before and after pavement construction. Undisturbed soil samples were also extracted and tested in the laboratory for MR. Regression models were developed to correlate MR with DCPI for fine-grained and coarse-grained soils, accounting for other physical properties. Results suggest ADCP can reliably estimate MR and detect changes in subgrade stiffness from pavement loading.
This document discusses using geostatistical analysis to understand soil moisture dynamics at a small catchment scale. Daily soil moisture data from 111 sensors over 3.5 years was analyzed. Variogram analysis showed limitations in accurately estimating the nugget variance without paired sensors. Kriging interpolation was performed, but results were limited by inaccurate variograms that were sometimes unbounded with high sill and range values. The analysis demonstrated the importance of accurately estimating the nugget variance for robust geostatistical modeling of soil moisture dynamics.
This document discusses modeling groyne placement on river bends based on sedimentation analysis using numerical simulation with the finite difference method. The goal is to determine optimal groyne placement by considering sediment accumulation volumes in groyne fields.
The study plans to simulate 450 cases combining various groyne positions, lengths, flow velocities, bend radii, and suspended sediment concentrations. Conservation equations for mass and momentum will be used to develop the mathematical model. Validation and verification processes will evaluate the agreement between experimental data and model predictions.
Regression analysis of simulation results will determine suitability coefficients to obtain relationships between parameters like Froude number and groyne length, providing guidance on best distances between groynes. The numerical model aims
Pore scale dynamics and the interpretation of flow processes - Martin Blunt, Imperial College London, at UKCCSRC specialist meeting Flow and Transport for CO2 Storage, 29-30 October 2015
This document summarizes a study that uses fractal geometry to predict permeability from other rock properties like porosity. It presents a new approach based on fractal models of pore space. The study derives relationships between permeability and pore radius distributions or porosity for different rock types using data from 640 sandstone samples. These relationships take the form of power laws with parameters calibrated for each rock type. The predicted permeabilities compare well to measured values. This approach provides a petrophysically justified way to estimate permeability from commonly available well log properties like porosity.
CO2-Driven Enhanced Gas Recovery and Storage in Depleted Shale Reservoir- A N...Steve Wittrig
1) The document discusses using numerical simulation to analyze CO2-enhanced gas recovery and storage in depleted shale gas reservoirs. It aims to maximize methane production while delaying CO2 breakthrough and maximizing CO2 storage.
2) Different injection scenarios are defined based on modifications to well patterns, reservoir characteristics, fracture properties, sorption parameters, and operational constraints. The scenarios vary the spacing between injection and production wells.
3) The best injection practice will be proposed based on analyzing different scenarios to enhance methane recovery and minimize CO2 production from the reservoir while storing more CO2.
This document summarizes research analyzing groundwater flow processes in fractured chalk rock in the United Kingdom under both pumped and ambient conditions. Key findings include:
1) Under pumped conditions, flow was concentrated along four discrete fractures with good agreement between different flow measurement methods.
2) Under ambient conditions, the system was more complicated with apparent cross-flow occurring over the upper 29 meters complicating measurement interpretations.
3) Estimates of aquifer transmissivity from different analysis methods ranged from 2,049 to over 4,388 square meters per day, with discrepancies attributed to non-linear head losses and some flows bypassing the upper 29 meter region during pumping.
1. The document defines key rock physics terms including density, porosity, saturation, velocity, impedance, Poisson's ratio, and reflection coefficients. Equations are provided for calculating these values from measured properties.
2. Methods of modeling reflection seismograms are described including normal reflection, reflection at an angle using Zoeppritz equations, AVO analysis, and impedance inversion.
3. Concepts of stress, strain, elasticity, elastic moduli, and their relationships to velocity are covered. The differences between static and dynamic moduli are also discussed.
1) The document discusses assessing uncertainty in time-lapse seismic response due to geomechanical deformation.
2) It presents a multi-physics solution that couples fluid flow and geomechanics modeling to better understand stress changes over time.
3) An example application to the Valhall oil field models pore pressure changes and resulting geomechanical effects, partitioning the domain for parallel modeling of the overburden, reservoir, and underburden.
This study used elastic impedance inversion and pre-stack attribute analysis on 3D seismic data with limited well control to identify productive zones in an offshore Iranian reservoir. Poisson dampening factor and Lame parameters extracted from pre-stack simultaneous inversion effectively delineated hydrocarbon-bearing areas, validated by crossplots of elastic impedance volumes. The attribute analysis results at well locations were generalized to the full seismic volume since the reservoir was considered laterally homogeneous.
This document summarizes the analysis of petrophysical data from two wells in the Upper Spraberry Formation to develop a rock-fluid model. Six distinct rock types were identified based on unique pore geometry, mineral composition, and fluid flow characteristics. Laboratory analysis of core plugs using nitrogen, helium, and mercury injection characterized porosity, permeability, pore size distribution, and wettability of each rock type. Clean sandy rocks generally had higher porosity and permeability than shaly or dolostone units. Integration of petrophysical data with log responses and core descriptions allowed differentiation of reservoir-quality from lower-quality rock intervals in the formation.
1. AVO inversion and processing of seismic data from the Penguin Field was challenging due to noise in the data and lack of clear AVO trends.
2. Pre-stack diagnostics identified issues like residual moveout and multiples that were addressed through additional processing steps.
3. Post-stack diagnostics on near, mid, and far stacks helped assess whether the data obeyed expected AVO behavior needed for inversion.
4. Inversion results for properties like Vshale, porosity, and net-to-gross ratio showed improved detail compared to original reservoir models.
INGENUITY IN SOIL REINFORCEMENT METHODS AGAINST SCOUR FAILUREEdison Mugoya
GEOTECHNICAL ENGINEERING: INGENUITY IN SOIL
REINFORCEMENT METHODS AGAINST SCOUR FAILURE
is a study in geotechnical engineering regarding the scour failure at bridge abutments. its a methodology used to decrease it's effects and prolong the life cycle of bridge piers
Retrofitting the well foundation of a railway bridge subjected to scourSushil Dhungana
This document discusses retrofitting techniques for strengthening the well foundation of a railway bridge subjected to scour. It proposes two retrofitting methods: 1) Installing piles around the well foundation, but finds this would not fully transfer loads or relieve pressure. 2) Creating a shallow foundation around the well to partly transfer vertical loads, all moments, and protect against scour in the top 2.5-3m. Analysis shows bearing pressure is within capacity even for increased modern loading standards. The revised approach of a reinforced concrete ring foundation is suggested to strengthen the existing well foundation against failure due to bending stresses or scour.
A clear water scour around a circular bridge pier under steady flow for diffe...eSAT Journals
Abstract The loose non cohesive material through which a river flows is generally called sediment. Local scour at piers and abutments is the main reason for the collapse of bridges founded in alluvial sediments. Clear water scour refers to the situation where no sediment is supplied by the approaching flow in the zone of scour. Many investigators have studied various aspects of scour. However, the study on scour under steady condition for same discharge with same depth of flow for different pier diameters is limited. In present study laboratory experiment was conducted on different pier sizes of circular piers by keeping discharge constant under clear water scour condition. It is found that Non dimensional scour depth gradient is different up to opening ratio 0.8 having less slope and its slope is steep above 0.8 opening ratio. Keywords: -clear water scour; Froude’s number; sediment; equilibrium scour.
HYDRAULIC JUMP CHARACTERISTICS FOR DIFFERENT OPEN CHANNEL AND STILLING BASIN ...IAEME Publication
Hydraulic jump is considered as the best way for dissipating energy present in moving water downstream of hydraulic structures. This paper conducted laboratory experiments to investigate the hydraulic jump characteristics variations for different rectangular open channel layouts. In this paper, the used open channel layouts were five bed slopes of 0.0175, 0.0349, 0.0524, 0.0699, and 0.0875, and a sill with three different heights was placed along a model of the stilling basin at three different longitudinal distances. The characteristics of the hydraulic jump, which was formed downstream vertical gate, were measured for variable discharges.
This document summarizes a HECRAS sediment transport computational study for the removal of a low head dam on the Mahoning River. The study modeled 33.5 river miles encompassing two Ohio counties over a year-long period. Key findings were that the dam removal would result in over 230,000 additional tons of sediment transport downstream, accumulating above the next dam. Sediment movement increased during high flow conditions. Pre-removal sediment transport studies can help manage issues from increased sediment load.
1) Nile Research Institute conducted a study of local scour at the El-Minia Bridge piers in Egypt. Field investigations found that the river bed had changed around the bridge piers, with a maximum local scour depth of 4.6 meters occurring between 1982 and 2002.
2) A computer model (HEC-RAS) was used to simulate local scour for a flow of 180 cubic meters per second. The model results showed the contraction and pier scour depths expected for this flow condition. Maximum local scour depths were computed for each bridge pier.
3) Studying local scour is important for evaluating scour risks and impacts to bridge foundations, and for proposing mitigation measures to
Scour investigation around single and two piers sidebyside arrangementeSAT Journals
Abstract Laboratory experiments concerning scour development around single and two piers side by side arrangement have been conducted in order to provide a comparison of scour depths and patterns. The experiments are carried out under unidirectional currents of clear-water scour conditions. A variety of conditions including different flow depths, pier diameters and pier spacing are considered to have significant influence on the development of the potential scour hole. The research on local scour around single and two piers side by side arrangement are studied by using a 15.24 m long, 0.46 m wide and 0.4 m deep flume in the Hydraulics and Hydrology Laboratory, Universiti Teknologi Malaysia (UTM).Experimental results describing the scour-hole depths and patterns are discussed. The results show that the magnitude and extent of the scour depth depends directly on pier size, pier spacing and flow condition. Piers, which are larger in diameter, produced greater scour depth. It also shows that by increasing the pier spacing, the scour depth around two piers decreases and closes to values of single pier. The two piers act as an obstruction which disturbed the flow field and caused large turbulence levels to be generated. Thereby, a further increase in the scouring velocity is produced giving relatively higher scour depth values. The prime factors governing the local scouring process associated with piers are pier spacing, horseshoe vortex, reinforcing and sheltering. The results show that good agreement with previous study where the down flow causes of increased scour for a single pier case. Meanwhile, the horseshoe vortex appears to be the main cause of scour in the case of two piers side by side arrangement. Keywords: Scour depth, Flow pattern, Single pier, Side by side piers, Pier spacing, Horseshoe vortex
The document summarizes a student presentation on observing hydraulic jumps in underground drainage systems. The student's objectives were to observe the behavior of flows and resulting hydraulic jumps inside closed conduits, and to compare this to classical hydraulic jumps. The methodology involved setting up experiments in a glass flume and using pressure sensors to measure velocities and pressures as hydraulic jumps formed. Results showed classical hydraulic jumps could be generated and compared to theoretical equations.
Quick tutorial of how to conduct a bridge scour computation within HECRAS. Characteristics of stream stability fundamentals are also discussed. Abutment, pier, and contraction methodologies from HEC 18 are summarized. Tips to avoid common mistakes are provided. Helpful data sources to assist design are suggested.
Estimation of bridge pier scour for clear water & live bed scour conditionIAEME Publication
1) The document analyzes and compares several equations for estimating bridge pier scour depth under clear water and live bed conditions.
2) Statistical tests are used to validate the equations against experimental laboratory data from previous studies. The tests analyzed include Theil's Coefficient, Mean Absolute Error, and Root Mean Square Error.
3) The results show that for both clear water and live bed scour conditions, the Richardson equation generally provides the most reasonable estimates of scour depth compared to other common methods, according to the statistical test values.
EXPERIMENTAL STUDY OF BRIDGE PIER SHAPE TO MINIMIZE LOCAL SCOURIAEME Publication
The study of local scour around bridge piers is very important for safe design of piers and other hydraulic structures. In this study, shape of pier is the main concern with three different velocities (0.18, 0.25, and 0.3) m/sec and other parameters like flow depth, bed material and etc. are remain same for all experiments. The experiments were conducted using laboratory flume, operated under the clear water condition using sand as a bed material. The test program was done on ten different shapes, Circular, Rectangular, Octagonal, Chamfered, Hexagonal, Elliptical, Sharp, Joukowsky, Oblong, streamline. were used to investigate the effect of the bridge pier's shape on local scour to conclude the optimal shape that gives minimum depth of scour. Comparison of results show that scour at upstream is directly proportional to exposed area of upstream nose of pier.
A broad crested weir with a crest height of 0.3m is located in a channel. With a measured head of 0.6m above the crest, the problem asks to calculate the rate of discharge per unit width, accounting for velocity of approach. Broad crested weirs follow the relationship that discharge per unit width (q) is proportional to the head (H) raised to the power of 3/2. Using this relationship and the given values of 0.3m for crest height and 0.6m for head, the problem is solved through trial and error to find the value of q.
Coffer dams are temporary structures built to retain water and soil in order to create a dry work area for construction projects. There are several types of coffer dams suited to different conditions, including earth-filled, sheet pile, and cellular designs. Key considerations in selecting a coffer dam include water depth, area size, soil/river bed conditions, and potential for erosion or flooding. Proper design is needed to withstand hydrostatic pressures and ensure structural integrity until the permanent structure is complete.
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Early kick detection and nonlinear behavior of drilling mu…Frank-Michael Jäger
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This document summarizes research on the effect of local scour on the foundations of hydraulic structures like bridge piers and abutments. It discusses factors that influence local scour depth around pile groups, including pile shape, spacing between piles, and arrangement. Laboratory experiments were conducted using a flume to model local scour at circular and square pile groups with varying spacings. The Florida Department of Transportation (FDOT) bridge scour evaluation program was also used to estimate scour depths. Results showed that scour depth decreases as pile spacing increases and is less for circular piles compared to square piles. The research highlights the importance of considering local scour effects in foundation design of hydraulic structures.
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International Journal of Engineering Research and DevelopmentIJERD Editor
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Material and Chemical Engineering,
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Mesoscopic simulation of incompressible fluid flow in porous media
575-1708-1-SM
1. UN I V E R S I D A D D E L O S AN D E S
46
ABSTRACT
Laboratory experiments were conducted to measure lo-
cal scour around cylindrical piers in different arrange-
ments. Also experimental data was compiled for each
arrangement to develop semi-empirical equations by
means of statistical analyses. The methodology of Sa-
lim & Jones (1996) was tested with the experimental
data and a new equation to predict scouring in pile
groups is proposed. Finally the goodness of piers with
slot is verified as a mechanism to minimise the scouring
phenomenon.
INTRODUCTION
One of the main causes of failure of bridges in service
conditions is the phenomenon of local scouring around
the piers, making the prediction of the scouring depth a
very important issue during the design procedure. The
complexity of the theoretical analysis varies as different
physical phenomena occurring are taken into account,
such as vorticity and conditions of the sediments of the
bed, among others.
As a result, experimentation is needed as an alternative
of acquiring knowledge of this aspect of fluvial hydrau-
lics. This activity has been initiated at the Universidad
de los Andes through its hydraulics laboratory from
80's. The present study considers different arrange-
ments to study the phenomenon in cylindrical pier
groups and the protection given by a rectangular slot
through the pier. The study reported is confined to
scour in clear water.
EXPERIMENTS
Experimental conditions
The experiments were conducted in a flume 10-m long
and 1.20-m wide having a horizontal slope. The flume
had a working section with a sediment recess 0.15-m
deep, 1.20-m wide, 3 m long and located 4.0 m downs-
tream from the flume entrance. Details of the water recir-
culation system, discharge measurement, tailgate con-
trol, etc are given in Espinosa (1999).
The arrangements tested are shown in Figure 1. The
arrangement I is a single pier 0.17 m diameter. The arran-
gement II is a pier group transverse to the approach
flow, the diameter of the individual piers (D) is 0.17m
with a similar gap between them. The arrangement III is
also a pier group that has the piers at an angular spa-
cing of 120°. The diameter of the individual piers of the
group in relation to that of the circumscribing circle of
the pier group is such that any one of them can just
pass through the gap between the other two. In such an
arrangement, it can be shown that the ratio of pier dia-
meter to that of the circumscribing circle is 0.302.
Finally the arrangement IV is a single pier with a rectan-
LOCAL SCOUR AROUND BRIDGE PIERS- A
STUDY OF ITS EFFECTS AROUND CYLINDRICAL
PIER GROUPS
By Andrés Mauricio Espinosa Farfan1
and Chandra Nalluri2
1 Civil Enginer -ACI Ltda (Consulting Engineers), Bogotá - Colombia
2 Visiting Profesor at th Universidad de los Andes, Bogotá - Colombia
2. F a c u l t a d d e I n g e n i e r í a
47
Rojas (1998) and Martínez (1998) established 10 combi-
nations of discharge and flow depths relating to clear-
water conditions. Details of the hydraulic computatio-
ns and calibration of the experimental conditions are
given in Espinosa (1999). Before the start of each run,
the particular arrangement of pier groupings was inser-
ted centrally and vertically in the flume and the sedi-
ment in the working section was leveled perfectly
around the arrangement. The experimental database is
also described in Espinosa (1999).
Keeping in view the duration of experimental runs
adopted by researches in the past at the Universidad de
los Andes, a duration of 2 h was adopted in the present
study.
ANALYSIS OF RESULTS
Identification of Parameters
ARRANGEMENT I
For the arrangement I, one can write the following func-
tional relationship for maximum scour depth (ds) due to
clear water flow, that is, τb
/τc
<1.0 (Breusers & Raudkivi
1991; and Espinosa 1999)
= s
o
50
,,,Re,,
o
s ∆
τ
τ
b
Y
d
b
Frf
Y
d
c
b
(1)
where ∆s
; ;/)( s ρρρ − and ρ being the densities of
sediment and water respectively and ν/Re 0V.Y= ,
approach flow Reynolds number. Since 50b/d ∆s
and
c/ττb are constant in the present study, equation (1)
reduces to
=
b
Y
,FrRe,f
o
Y
s
d
o
(2)
The influence of each of the parameters show in equa-
tion (2) can be seen in Espinosa (1999). Apart from the-
se parameters, the importance of the parameter 50b/d
over the parameter 0s /Yd is observed with the aid of the
gular slot. The width (ω) of the rectangular slot equal to 0.33D extends to the full height of the solid pier. The
sediments used were cohesionless natural sands from a riverbed, with relative density of 2.65 and geometric mean
size (d50
)of0.52mm.
FIG. 1- Experimental Arrangements (all dimensions
in cm).
FIG. 2- Relationship between ds/Yo and Froude
number for different relations of b/d50.
RELATIONSHIP ds/Yo vs Fr.
For differents b/d50 ratios and clear-water scour
0
0,5
1
1,5
2
2,5
0 0,2 0,4 0,6 0,8 1 1,2 1,4Fr
ds/Yo
b/D50=17 (Charber&Engendilger) b/D50=50(Charber&Engendilger)
b/D50=238(M aza&Sanchez) b/D50=324(Espinosa)
3. UN I V E R S I D A D D E L O S AN D E S
48
data found in the literature, and compared with the present value - see Figure 2.
Figure 2, leads to the observations:
· As the ratio 50b/d increases at a given Froude number, the value of the parameter 0s /Yd also increases. This is due
to the capability of the flow moving the finest material with respect to the pier width for a given Froude number.
· There appears to be a limiting Froude number after which, the value of 0s /Yd is independent of Froude number for
a given 50b/d ratio.
Incorporating this information on the influence of the parameter 50b/d and using statistical package (SSPS for
Windows) the following equation is written as:
152.0
50
543.0
028.0659.0
Re611.0
⋅
⋅⋅⋅=
d
b
b
Y
Fr
o
Y
s
d
o
with (R2
) = 0.83 (3)
Changing the dependent variable ( 0s /Yd ) for one relating to the scouring depth with the mean diameter of the
sediment ( 50s/dd ) and ignoring the effect of Reynolds number due to its little significance in the phenomenon (see the
exponent in equation (3)), is possible to get a better fit of the experimental data. Suggesting:
499.0
s
603.0
966.0
237.1
50
946.0 −
⋅
⋅⋅
⋅= ∆
b
Y
Fr
d
b
d
d o
50
s with (R2
) = 0.98 (4)
Figure 3 shows the goodness of fit of the experimental data as for equations (3) and (4)
FIG. 3 - (ds
/Yo
)obs
vs
(ds
/Yo
)calc
and (ds
/d50
)obs
vs
(ds
/d50
)calc
according to eq. (3) - Fig 3(a)- and eq. (4) - Fig 4(b).
(ds/Yo)obs vs (ds/Yo)calc
0,00
0,50
1,00
1,50
2,00
2,50
0,00 0,50 1,00 1,50 2,00 2,50
(ds/Yo)calc
(ds/Yo)obs
(ds/d50)obs vs (ds/d50)calc
0
100
200
300
400
500
600
700
800
900
0 100 200 300 400 500 600 700 800 900
(ds/d50)calc
(ds/d50)obs
Equations (3) and (4) are only valid for clear-water
scour around circular piers. For other geometrical sha-
pes the shape correction factors given in the literature
can be applied.
ARRANGEMENT II
Salim & Jones (1996) (see Figure 4) developed a metho-
dology that can be used to determine scour depth at
pile groups. Taking the local pier scour equation recom-
mended by Federal Highway Administration (FHWA,
CircularHEC-18)asaframeofreference,theyintroduced
a new correction factor (Ks, spacing correction factor)
which is the ratio of scour depth at a particular value of
therelativeseparation(s/b),wherebiswidthofthepier,to
that of equivalent solid pier for the same pile group confi-
guration. The equation is stated as:
4. F a c u l t a d d e I n g e n i e r í a
49
( ) s
o
321
o
s
KFr
Y
D
KKK
Y
d
=
43.0
65.0
0.2 (5)
where:
K1
= shape factor (1.1 for square nose, 1.0
for round nose, 0.9 for sharp nose).
K2
= angle of attack factor.
K3
= dune factor (varies from 1.0 to 1.3).
Ks
= spacing correction factor estimated from:
)1(5.0)1(
)1( s/b-s/b-
s eeAk +−= where A varies
from 0.47 to 0.57.
D = width of the equivalent solid pier or
the width of the pile group if the piles
were packed to touch one another; and
Fr
= Approach Froude number 0gYV/= .
FIG. 4 - Definition sketch for Methodology of Salim
& Jones (1996).
FIG. 5- Local Scour equations for arrangement II.
Applying these concepts to the present experimental
data, Figure 5 (a) suggests that this methodology over-
estimates the observed scour, even if the span between
piers is taken into account. This may be explained be-
cause the methodology is based on the local pier scour
equation recommended by Federal Highway Adminis-
tration -Salim & Jones (1996) - which is known to be
conservative in predicting the scour.
(a)Results after the methodology of
Salim&Jones (1996).
(b)Results from equation
(7).
(ds/Yo)obs vs (ds/Yo)calc
Methodology of Salim&Jones(1996)
0,0
0,5
1,0
1,5
2,0
2,5
0,0 0,5 1,0 1,5 2,0 2,5
(ds/Yo)calc
(ds/Yo)o
bs
Piers touching Considering the gap between the piers
(ds/d50)obs vs. (ds/d50)calc
0
50
100
150
200
0 50 100 150 200
(ds/d50)calc
(ds/d50)obs
Keeping in mind the concept of spacing correction fac-
tor (Ks
) introduced by these authors, one can modify
the functional relationship for scour depth proposed
for arrangement I (see equation (1)) into the following
form:
= s
c
b
,,,Re,, ∆
τ
τ
'
o
50
'
50 b
Y
d
b
Frf
b
s
d
(6)
where sb/D.Kor in other words b' is the effective width
of the pile. Based on statistical analysis and recompiled
data equation (7) can be established (ignoring again
the approach Reynolds number to get better fit) - see
Figure 5 (b):
450.0
s
802.0278.0
336.1
73.377 ∆⋅
⋅
⋅⋅= '
o
50
'
50 b
Y
d
b
Fr
d
s
d
with (R2) = 0.98 (7)
Equation (7) is only valid for clear-water scour and cir-
cular piers aligned transverse to the approach flow. For
other geometrical shapes and orientations, the respecti-
ve correction factors (Salim &Jones - 1996) can be
applied.
ARRANGEMENT III
For this arrangement, the width (b) of the group will be
taken as the one associated to the diameter of the cir-
5. UN I V E R S I D A D D E L O S AN D E S
50
Using the functional relationship of equation (8) the following empirical equation (model) is deduced (The parameter
cb /ττ is now included because is not constant in the experimental database for this arrangement and the approach
Reynolds number is ignored due to its little influence):
118.1125.0316.0
50
146.1
0087.0
414.3
⋅
⋅
⋅
⋅⋅=
−−
C
Bo
b
B
d
b
b
Y
Fr
o
Y
s
d
τ
τ
(9)
with a correlation coefficient of 0.99 (see Figure 6 (b)). The reason for not including the submerged specific gravity
of the material (as it had been done for the previous arrangements) is because the available data in the literature for
this type of configuration are only for sand; equally, the influence of Fr seem to be negligible in equation (9).
ARRANGEMENT IV
In order to include the effect that the slot has, the functional relation should comprise (besides the parameters
previously mentioned) relationships indicating the effect the height of the slot has with respect to the depth of the
approaching flow 0L/YY and the width of the slot with respect to the pier size w/b . (Vittal et al (1994)) - see Figure
7(a). Based on this, the functional relationship of the variables involved in the phenomenon for this type of arrange-
ment has the following structure:
=
o
Lo
Y
Y
,
b
w
,
b
Y
d
b
Frf
o
Y
s
d
,,Re,,
50c
b
τ
τ
(10)
cumscribing circle of the pier group. According to what was reported by Vittal et al (1994), it is known that for this sort
of arrangement the orientation of the group with respect to the flow is a significant variable in the expected value for
local scouring. For the arrangement III, one can write the following functional relationship for scour depth (ds) due to
clear water flow, that is, cb /ττ <1.0 (Espinosa 1999).
= s
50c
b
,,,,Re,, ∆
τ
τ
b
B
b
Y
d
b
Frf
o
Y
s
d
o
(8)
where B is that represented by the portion of the width of the single piers which is projected in a plane perpendicular
to the direction of the approaching flow and is a function of the orientation of the group with respect to approach
flow. See Figure 6 (a) (width B represented by the summation of gray lines in each case).
(a) Diagramatic sketch (b) Results for arrangement III.
FIG. 6 - Diagramatic sketch and results for arrangement III.
(ds/Yo)calc vs (ds/Yo)obs
0,00
0,20
0,40
0,60
0,80
1,00
1,20
1,40
1,60
1,80
0,00 0,20 0,40 0,60 0,80 1,00 1,20 1,40 1,60 1,80
(ds/Yo)calc
(ds/Yo)obs
6. F a c u l t a d d e I n g e n i e r í a
51
Comparing the functional relationships proposed for
arrangements I and IV (equations (1) and (10)), and ac-
cording to what was stated by Vittal et al (1994) the
relationship between the observed scouring in arrange-
ment I ( sId ) and the one observed for arrangement IV
( sIVd ) can be expressed as:
=
o
L
sI
sIV
Y
Y
,
b
w
f
d
d
(11)
In addition, the parameters w/b and 0L/YY were kept
constant in the present study, which implies that equa-
tion (11) will transform to:
cte
d
d
sI
sIV
= (12)
As it can be observed, what was found in equation (12)
is partially confirmed, with the lines tending to be para-
llel -see Figure 7 (b)- suggesting a mean value of 0.69 for
this ratio.
CONCLUSIONS
The study reveals the following:
· The adimensional parameters of that determine the
scouring depth are: the relationship of the width of the
pier(orgroup)tothemeandiameterofthebedmaterial
( 50b/d );Froudenumberfortheapproachingflow(Fr);
relationship of the approaching flow depth to the width
of the pier (or group) ( /b0Y ); the submerged specific
gravity of the bed material ( s∆ ); and the relationship
between the shear stress of the bed and the critical
shear stress for movement to initiate ( c/ττb ).
· For arrangement III, in addition to the parameters
previously mentioned, the orientation of the group
with respect to the approaching flow is also a signi-
ficant variable. In arrangement IV, the relationships
between the width of the slot to the width of the pier
( w/b ) and between the height of the slot to the
approaching depth ( 0L /YY ) also intervene.
· In contradiction to that was reported in the literature,
using the dimensionless parameter ( 50s /dd ) in the
functional equations, implies a better fit than to the
equations that use ( 0s /Yd ) as dependent variable for
arrangements in I and II.
· The slot system results in an effective protective me-
chanism (around 30% reduction in scour depth for
w/b = 0.302 and 0L /YY = 1) for the phenomenon of
local scouring. However, its efficiency depends of
the parameters w/b and 0L /YY which need further
investigation for a better generalisation.
ACKNOWLEDGEMENT
The authors wish to express their appreciation to Juan
Saldarriaga; Dean of Research at the Universidad de los
Andes for his comments and the financial support pro-
vided to carry out the experimental work.
(a) Definition sketch. (b) Protection given by slotted systems.
FIG. 7 - Definition sketch and results for arrangement IV.
C om pa ris o n b e tw e e n
A rra nge m e nt I a nd Arr a ng e m e n t IV
0,00
0,10
0,20
0,30
0,40
0,50
0,60
0,70
0,00 0,05 0,10 0,15 0,20 0,25
F r
ds/Yo
A r ran gem en t IV A r ran gem en t I
7. UN I V E R S I D A D D E L O S AN D E S
52
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