Coarse soils can contain flaky grains in addition to rounded or angular grains, along with a vary... more Coarse soils can contain flaky grains in addition to rounded or angular grains, along with a varying fines content. Depending on the regional geology, however, the mica grain content can be remarkable, reaching 30 % or higher. Therefore, it is reasonable to expect that mica grains would affect the soil behaviour. In this study, soils of a delta deposit that are known to involve mica grains were examined. The river sand was considered as the host material and the mica grain contents were determined by means of the flotation technique. A correlation between the mica content as found using the flotation technique and XRD count numbers obtained using an X-ray diffraction test method for each soil sample was established. The standard penetration test (SPT) blow counts from various boreholes were interpreted from the mica content’s influence point of view. The results showed that the mica grains would reduce the SPT resistance at certain fines-content, host-sand, mica-grain combinations. ...
ABSTRACT Digital image processing algorithms for the analysis and characterization of grains and ... more ABSTRACT Digital image processing algorithms for the analysis and characterization of grains and voids in cemented materials were developed using toolbox functions of a mathematical software package. Utilization of grayscale, color and watershed segmentation algorithms and their performances were demonstrated on artificially prepared self-compacting concrete (SCC) samples. It has been found that color segmentation was more advantageous over the gray scale segmentation for the detection of voids whereas the latter method provided satisfying results for the aggregate grains due to the sharp contrast between their colors and the cohesive matrix. The watershed segmentation method, on the other hand, appeared to be very efficient while separating touching objects in digital images.
ABSTRACT A color based segmentation procedure and a modified signature technique have been applie... more ABSTRACT A color based segmentation procedure and a modified signature technique have been applied to the detection and analyses of complicated void shapes in cemented materials. The gray-scale segmentation and available signature methods were found to be inefficient especially for the analyses of complicated void shapes. The applicability of the developed methodology has been demonstrated on artificially prepared cemented materials made of self compacted concrete material. In order to characterize the void shapes in the investigated sample images, two new shape parameters called as coefficients of inclusion and exclusion have been proposed. When compared with the traditional use of the signature method, it was found that the methodology followed herein would better characterize complicated void shapes. The methodology followed in this study may be applied to the analysis of complicated void shapes that are often encountered in other cementitious materials such as clays and rocks.
A key parameter in the design of a laterally loaded pile is the determination of its performance ... more A key parameter in the design of a laterally loaded pile is the determination of its performance level. Performance level of a pile is usually expressed as the maximum head deflection and bending moment. In general, uncertainties in the performance of a pile originates from many factors such as inherent variability of soil properties, inadequate soil exploration programs, errors taking place in the determination of soil parameters, limited calculation models as well as uncertainties in loads. This makes it difficult for practicing engineers to decide for the reliability of laterally loaded piles both in cohesive and cohesionless soils. In this paper, limit state functions and consequent performance functions are obtained for single concrete piles to predict the maximum bending moment, a widely accepted design criterion along with the permissible pile head displacement. Analyses were made utilizing three dimensional finite element method and soil-structure-interaction (SSI) effects were accounted for.
... DEÜ., İzmir, serkan.misir@deu.edu.tr 3 Yrd.Doç.Dr., DEÜ., İzmir, gurkan.ozden@deu.edu.tr Page... more ... DEÜ., İzmir, serkan.misir@deu.edu.tr 3 Yrd.Doç.Dr., DEÜ., İzmir, gurkan.ozden@deu.edu.tr Page 2. 218 Temel Alanı iç. Sbt ve Değişken Yatak Kats. Yakl. Yapı Davr. Etkisi GİRİŞ Konsolidasyona bağlı olarak gelişen toplam ve farklı oturma problemlerine özellikle yumuşak kil ...
The interplay between fine and coarse grains of a soil matrix has attracted attention of research... more The interplay between fine and coarse grains of a soil matrix has attracted attention of researchers following recent field observations of liquefied soils containing varying amount of fines with different characteristics. However, similar studies have not been performed as intensively for the compression characteristics of these soils. It should be expected that intergranular void ratio would play a role on the compressional stress-strain characteristics of soils consisting of fine and coarse grains of different percentages. In this study an attempt has been made in order to understand influence of intergranular void ratio on 1-D compressional soil behavior. Laboratory tests on reconstituted sand and kaolinite mixtures have indicated that there is a threshold value of fines content that can be named as transition fines content, below which the compressional behavior is mainly controlled by the coarser grain matrix and above which it is the finer grain matrix that governs. This tran...
In this study, influence of fine and coarse grain percentage on porosity and stress-strain behavi... more In this study, influence of fine and coarse grain percentage on porosity and stress-strain behavior of mixtures that were composed of different percentages of fine and coarse grains were investigated by means of fall cone and oedometer tests. In addition to this, an attempt has been made in order to explain related behavior of the mixtures, which is affected by interchange of the dominance between the coarse and fine grain matrices, utilizing intergranular and interfine void ratio concepts.
It has been demonstrated in previous observations following major earthquakes that almost all typ... more It has been demonstrated in previous observations following major earthquakes that almost all types of piles with varying sectional characteristics were damaged. Somehow arbitrary precautions such as increasing pile dimensions or reinforcement to avoid damages were proved to be inadequate for satisfactory pile design under seismic loads. This fact necessitated research for piles that are more resistant to earthquake forces. Recent debate has been about the design and construction of ductile piles. In this respect, steel fiber reinforced concrete (SFRC) can be considered as a contemporary material being able to provide desired additional ductility to conventional reinforced concrete (RC) piles. The present has targeted investigation of lateral load carrying capacity of SFRC piles in cohesionless soils. A modeling study involving instrumented model piles, a testing pool and a monotonic loading mechanism has been planned and pursued. Several steel fiber ratios by volume and three types...
In this study, the effects of pile spacing and pile head fixity on the moment and lateral soil pr... more In this study, the effects of pile spacing and pile head fixity on the moment and lateral soil pressure distribution along slope stabilizing piles are investigated. A slice from an infinitely long row of piles with fixed pile tip in an inclined sand bed was simulated with an experimental test setup. Surficial soil displacements were monitored and relative displacements between soil particles were determined by recording time-lapse images during the test in order to observe the soil arching mechanism on the soil surface. The load transfer process from moving soil to piles and behavior of soil around piles were observed and evaluated by the different test setups. It was observed that decrease in pile spacing causes an increase of load carried per pile. This behavior, which was significantly influenced by the pile head boundary conditions, can only be explained by soil arching that existed between the piles along their lengths.
A better understanding of the inertial loads on pile response during a seismic event is the subje... more A better understanding of the inertial loads on pile response during a seismic event is the subject of this study. Effects of loading rate, initial effective overburden stress and inertial excess pore-water pressure on soil-pile springs are investigated. Development of a new nonlinear p-y model that is capable of expressing the effective stress state in the immediate neighborhood of the laterally loaded pile is the ultimate objective of the research. ^ In order to achieve the objectives of the research, a new experimental set-up that can simulate the inertial effects on soil-pile interaction was developed. Using this experimental set-up, excess pore-water pressure and force-displacement data were acquired. Using the experimental data, the effects of loading rate and excess pore-water pressure development on soil-pile interaction were demonstrated. Finally, p-y models that account for excess pore-water pressure and loading rate effects were proposed. ^
Volumetric shrinkage of compacted bentonite and sand mixtures has been continuously monitored at ... more Volumetric shrinkage of compacted bentonite and sand mixtures has been continuously monitored at small strain levels (i.e., <5 %) using a digital image processing technique. A special digital measurement setup and a computer algorithm have been developed in order to identify volume of the drying specimens. Volume change of three compacted bentonite-sand mixtures at different initial moisture contents were recorded during drying by means of vernier caliper and digital measurements. Continuous monitoring of the volumetric shrinkage of specimens using digital images proved that digital measurement and data reduction methodology developed herein is capable of determining the shrinkage amount with desired accuracy. It is shown in the study that consistent volumetric shrinkage strain readings can be taken using this cost effective, nondestructive, and operator independent measurement setup, which may have become the preferred shrinkage measurement methodology in soil mechanics laboratory practice with some added features.
Adapting image processing technology to engineering disciplines can be useful in the evaluation o... more Adapting image processing technology to engineering disciplines can be useful in the evaluation of the mechanical behavior of materials. Not only characteristics of granular materials, but also particulate levels of colloids can be studied using image analysis. Attempts to identify the ...
Clayey sand can be considered as a composite matrix of coarse and fine grains. The interaction be... more Clayey sand can be considered as a composite matrix of coarse and fine grains. The interaction between coarser and finer grain matrices affects the overall stress–strain behavior of these soils. Intergranular void ratio, es (which is the void ratio of the coarser grain matrix) can be utilized as an alternative parameter to express the compressive response of such soils. Oedometer
Coarse soils can contain flaky grains in addition to rounded or angular grains, along with a vary... more Coarse soils can contain flaky grains in addition to rounded or angular grains, along with a varying fines content. Depending on the regional geology, however, the mica grain content can be remarkable, reaching 30 % or higher. Therefore, it is reasonable to expect that mica grains would affect the soil behaviour. In this study, soils of a delta deposit that are known to involve mica grains were examined. The river sand was considered as the host material and the mica grain contents were determined by means of the flotation technique. A correlation between the mica content as found using the flotation technique and XRD count numbers obtained using an X-ray diffraction test method for each soil sample was established. The standard penetration test (SPT) blow counts from various boreholes were interpreted from the mica content’s influence point of view. The results showed that the mica grains would reduce the SPT resistance at certain fines-content, host-sand, mica-grain combinations. ...
ABSTRACT Digital image processing algorithms for the analysis and characterization of grains and ... more ABSTRACT Digital image processing algorithms for the analysis and characterization of grains and voids in cemented materials were developed using toolbox functions of a mathematical software package. Utilization of grayscale, color and watershed segmentation algorithms and their performances were demonstrated on artificially prepared self-compacting concrete (SCC) samples. It has been found that color segmentation was more advantageous over the gray scale segmentation for the detection of voids whereas the latter method provided satisfying results for the aggregate grains due to the sharp contrast between their colors and the cohesive matrix. The watershed segmentation method, on the other hand, appeared to be very efficient while separating touching objects in digital images.
ABSTRACT A color based segmentation procedure and a modified signature technique have been applie... more ABSTRACT A color based segmentation procedure and a modified signature technique have been applied to the detection and analyses of complicated void shapes in cemented materials. The gray-scale segmentation and available signature methods were found to be inefficient especially for the analyses of complicated void shapes. The applicability of the developed methodology has been demonstrated on artificially prepared cemented materials made of self compacted concrete material. In order to characterize the void shapes in the investigated sample images, two new shape parameters called as coefficients of inclusion and exclusion have been proposed. When compared with the traditional use of the signature method, it was found that the methodology followed herein would better characterize complicated void shapes. The methodology followed in this study may be applied to the analysis of complicated void shapes that are often encountered in other cementitious materials such as clays and rocks.
A key parameter in the design of a laterally loaded pile is the determination of its performance ... more A key parameter in the design of a laterally loaded pile is the determination of its performance level. Performance level of a pile is usually expressed as the maximum head deflection and bending moment. In general, uncertainties in the performance of a pile originates from many factors such as inherent variability of soil properties, inadequate soil exploration programs, errors taking place in the determination of soil parameters, limited calculation models as well as uncertainties in loads. This makes it difficult for practicing engineers to decide for the reliability of laterally loaded piles both in cohesive and cohesionless soils. In this paper, limit state functions and consequent performance functions are obtained for single concrete piles to predict the maximum bending moment, a widely accepted design criterion along with the permissible pile head displacement. Analyses were made utilizing three dimensional finite element method and soil-structure-interaction (SSI) effects were accounted for.
... DEÜ., İzmir, serkan.misir@deu.edu.tr 3 Yrd.Doç.Dr., DEÜ., İzmir, gurkan.ozden@deu.edu.tr Page... more ... DEÜ., İzmir, serkan.misir@deu.edu.tr 3 Yrd.Doç.Dr., DEÜ., İzmir, gurkan.ozden@deu.edu.tr Page 2. 218 Temel Alanı iç. Sbt ve Değişken Yatak Kats. Yakl. Yapı Davr. Etkisi GİRİŞ Konsolidasyona bağlı olarak gelişen toplam ve farklı oturma problemlerine özellikle yumuşak kil ...
The interplay between fine and coarse grains of a soil matrix has attracted attention of research... more The interplay between fine and coarse grains of a soil matrix has attracted attention of researchers following recent field observations of liquefied soils containing varying amount of fines with different characteristics. However, similar studies have not been performed as intensively for the compression characteristics of these soils. It should be expected that intergranular void ratio would play a role on the compressional stress-strain characteristics of soils consisting of fine and coarse grains of different percentages. In this study an attempt has been made in order to understand influence of intergranular void ratio on 1-D compressional soil behavior. Laboratory tests on reconstituted sand and kaolinite mixtures have indicated that there is a threshold value of fines content that can be named as transition fines content, below which the compressional behavior is mainly controlled by the coarser grain matrix and above which it is the finer grain matrix that governs. This tran...
In this study, influence of fine and coarse grain percentage on porosity and stress-strain behavi... more In this study, influence of fine and coarse grain percentage on porosity and stress-strain behavior of mixtures that were composed of different percentages of fine and coarse grains were investigated by means of fall cone and oedometer tests. In addition to this, an attempt has been made in order to explain related behavior of the mixtures, which is affected by interchange of the dominance between the coarse and fine grain matrices, utilizing intergranular and interfine void ratio concepts.
It has been demonstrated in previous observations following major earthquakes that almost all typ... more It has been demonstrated in previous observations following major earthquakes that almost all types of piles with varying sectional characteristics were damaged. Somehow arbitrary precautions such as increasing pile dimensions or reinforcement to avoid damages were proved to be inadequate for satisfactory pile design under seismic loads. This fact necessitated research for piles that are more resistant to earthquake forces. Recent debate has been about the design and construction of ductile piles. In this respect, steel fiber reinforced concrete (SFRC) can be considered as a contemporary material being able to provide desired additional ductility to conventional reinforced concrete (RC) piles. The present has targeted investigation of lateral load carrying capacity of SFRC piles in cohesionless soils. A modeling study involving instrumented model piles, a testing pool and a monotonic loading mechanism has been planned and pursued. Several steel fiber ratios by volume and three types...
In this study, the effects of pile spacing and pile head fixity on the moment and lateral soil pr... more In this study, the effects of pile spacing and pile head fixity on the moment and lateral soil pressure distribution along slope stabilizing piles are investigated. A slice from an infinitely long row of piles with fixed pile tip in an inclined sand bed was simulated with an experimental test setup. Surficial soil displacements were monitored and relative displacements between soil particles were determined by recording time-lapse images during the test in order to observe the soil arching mechanism on the soil surface. The load transfer process from moving soil to piles and behavior of soil around piles were observed and evaluated by the different test setups. It was observed that decrease in pile spacing causes an increase of load carried per pile. This behavior, which was significantly influenced by the pile head boundary conditions, can only be explained by soil arching that existed between the piles along their lengths.
A better understanding of the inertial loads on pile response during a seismic event is the subje... more A better understanding of the inertial loads on pile response during a seismic event is the subject of this study. Effects of loading rate, initial effective overburden stress and inertial excess pore-water pressure on soil-pile springs are investigated. Development of a new nonlinear p-y model that is capable of expressing the effective stress state in the immediate neighborhood of the laterally loaded pile is the ultimate objective of the research. ^ In order to achieve the objectives of the research, a new experimental set-up that can simulate the inertial effects on soil-pile interaction was developed. Using this experimental set-up, excess pore-water pressure and force-displacement data were acquired. Using the experimental data, the effects of loading rate and excess pore-water pressure development on soil-pile interaction were demonstrated. Finally, p-y models that account for excess pore-water pressure and loading rate effects were proposed. ^
Volumetric shrinkage of compacted bentonite and sand mixtures has been continuously monitored at ... more Volumetric shrinkage of compacted bentonite and sand mixtures has been continuously monitored at small strain levels (i.e., <5 %) using a digital image processing technique. A special digital measurement setup and a computer algorithm have been developed in order to identify volume of the drying specimens. Volume change of three compacted bentonite-sand mixtures at different initial moisture contents were recorded during drying by means of vernier caliper and digital measurements. Continuous monitoring of the volumetric shrinkage of specimens using digital images proved that digital measurement and data reduction methodology developed herein is capable of determining the shrinkage amount with desired accuracy. It is shown in the study that consistent volumetric shrinkage strain readings can be taken using this cost effective, nondestructive, and operator independent measurement setup, which may have become the preferred shrinkage measurement methodology in soil mechanics laboratory practice with some added features.
Adapting image processing technology to engineering disciplines can be useful in the evaluation o... more Adapting image processing technology to engineering disciplines can be useful in the evaluation of the mechanical behavior of materials. Not only characteristics of granular materials, but also particulate levels of colloids can be studied using image analysis. Attempts to identify the ...
Clayey sand can be considered as a composite matrix of coarse and fine grains. The interaction be... more Clayey sand can be considered as a composite matrix of coarse and fine grains. The interaction between coarser and finer grain matrices affects the overall stress–strain behavior of these soils. Intergranular void ratio, es (which is the void ratio of the coarser grain matrix) can be utilized as an alternative parameter to express the compressive response of such soils. Oedometer
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