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Guoqing Jing - One of the best experts on this subject based on the ideXlab platform.
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Experimental and numerical investigations on the shear behaviour of recycled railway Ballast
Construction and Building Materials, 2019Co-Authors: Wenli Jia, Yunlong Guo, Valeri Markine, Guoqing JingAbstract:Abstract Ballast degradation is frequently observed under cyclic loading, and results in bearing capacity and drainage problem of Ballast track. To keep the stability and safety, periodical maintenances are needed, such as cleaning and replacement, which produce a huge amount of wasted Ballast. Thus, reusing the deteriorated Ballast can become a considerable method for sustainable railway development and environment protection. One applications is adding the cleaned deteriorated Ballast (i.e. recycled Ballast) into fresh Ballast. Furthermore, it is common situation that applying the mixture of fresh and deteriorated Ballast during the railway operation. To study the mechanical behaviour of this mixture and find out the criterion weight proportion of the recycled Ballast, a series of large direct shear tests were performed with different weight proportions (0%, 10%, 20%, 30%, 40%, and 50%) of recycled Ballast mixed into fresh Ballast under different normal stresses (50, 100 and 200 kPa). In addition, a numerical simulation based on discrete element method (DEM) was used to illustrate the shear strength, contact forces, coordination numbers and displacements of Ballast particles. Results show that the shear strength reduction of the mixture is insignificant, when mixed with less than 30% recycled Ballast. With the recycled Ballast proportion increasing, the shear strength and coordination number reduce and the displacements get larger. This research provides a foundation for the application of recycled Ballast, and on the other hands, adding fresh Ballast can be a solution to reinforce deteriorated Ballast Bed.
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Ballast degradation effect of particle size and shape using los angeles abrasion test and image analysis
Construction and Building Materials, 2018Co-Authors: Yunlong Guo, V L Markine, Jianing Song, Guoqing JingAbstract:Ballast track is the most widely used track for the railway transport, and Ballast Bed plays a significant role to provide resistances during train operation. Generally, the Ballast Bed consists of crushed stones. To achieve the mitigation of Ballast degradation, the first priority is to describe the degradation development and to study its effect factors. The influence of Ballast morphology (particle size and shape) on Ballast degradation is examined here using the Los Angeles Abrasion (LAA) test in combination with 3-D image analysis. LAA tests are used to obtain the deteriorated Ballast. Then, based on the 3-D images, the changes of Ballast particles after the tests were analysed. To quantify the Ballast degradation (abrasion and breakage), the Abrasion Depth based on the analysis of 3-D images were proposed, while Ballast breakage was estimated using the broken particles ratio. The results have shown that Ballast degradation is directly related to the Ballast morphology. The proposed image-based procedure can effectively be applied to assess Ballast degradation. The results can be used for Ballast material standardization, modelling of Ballast degradation process and maintenance cycle prediction.
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discrete element method of improved performance of railway Ballast Bed using elastic sleeper
Journal of Central South University, 2015Co-Authors: Liang Gao, Guoqing Jing, Qi Luo, Hanke JiangAbstract:With the development of high-speed and heavy-haul railway in China, problems like insufficient thickness of Ballast Bed and overlarge track stiffness are obvious. Ballast may break into small particles and their contact status will deteriorate under cyclic loading, resulting in Ballast degradation. Discrete element method (DEM) was used to research improved performance of Ballast Bed using elastic sleeper. Clusters were generated by bonding spheres to model real Ballasts, while broken bonds were utilized to distinguish breakage. Two kinds of Ballast Beds with elastic sleeper and conventional sleeper were established, respectively. After applying cyclic loading to the models, differences of mechanical properties between two models were analyzed by contrasting their dynamic behavior indexes, such as particle contact force, sleeper settlement, vibration velocity and acceleration, breakage characteristic. The results illustrate that compared with conventional sleeper, elastic sleeper increases sleeper settlement, while reduces Ballast vibration and contact force between particles, which could depress Ballast breakage.
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Micro-analysis of hanging sleeper dynamic interactions with Ballast Bed
'JVE International Ltd.', 2015Co-Authors: Guoqing Jing, Qi Luo, Zijie Wang, Yonggang ShenAbstract:The hanging sleeper under train dynamic loads result in discrete contact and breakage of Ballast particles, and accelerate Ballast Bed degradation and deformation. A sleeper-Ballast dynamic interaction model was established to analyze the effects of hanging sleeper due to the sleeper dynamic response. In this research, the Discrete Element Method (DEM) was applied to simulate the hanging sleeper dynamic characteristics of Ballast Bed, where the irregular Ballast particle was constructed by clusters, and the Ballast particle breakage under dynamic cyclic loads was investigated. The nonlinear contact force model of Mohr-Coulomb was adopted to model the cluster particles. The Ballast breakage function and dynamic simulation were employed, with local damping method. Numerical results indicated that hanging sleeper altered the contact force distribution state, the hanging sleepers would incur centralized contact force under sleepers, more Ballast particles breakage, and Ballast lateral resistance reduction varied with hanging sleeper situations. Some Ballasted track improvements should be considered in practice, such as increase thickness of Ballast Bed, improve Ballast compaction, and reduce vibration tamping produced voids
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Micro-analysis of lateral Ballast resistance of seismic characteristics
'JVE International Ltd.', 2014Co-Authors: Guoqing Jing, Qi Luo, Zijie Wang, Chuantao YinAbstract:The Ballast Bed becomes loose in the event of earthquake, as to track lateral resistance ability, even if no visible defects are found in on-site inspections. The behavior of Ballast materials subjected to earthquake vibrations is dependent on a variety of factors, including amplitude, frequency, as well as the particle properties, for example, Ballast degradation. Motivation for the investigation reported here is based on lateral Ballast resistance after vibration. In this research, the discrete element method (DEM) was applied to simulate the seismic characteristics of Ballast Bed, where the irregular Ballast particle was constructed; the interlock of Ballast can be well modeled. The nonlinear contact force model with Mohr-Coulomb is adopted to model the clumped particles. A full-size track on a shaking table DEM model was developed, the sleeper lateral Ballast resistance force index, and slope Ballast particle displacements were analyzed under different vibration accelerations, vibration duration and vibration frequencies, compared with existed same size tests. The purpose of such modeling is micro-analysis of Ballasted tracks under seismic effects. DEM test results clarified that sleeper lateral resistance was governed by seismic response. The lateral Ballast resistance decrease with vibration accelerations, vibration duration and vibration frequencies, agreed with the tests results
Jing Guoqing - One of the best experts on this subject based on the ideXlab platform.
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Analysis of furnace slag in railway sub-Ballast based on experimental tests and DEM simulations
'Elsevier BV', 2021Co-Authors: Jia W., Markine V.l., Jing GuoqingAbstract:Under the high requirement of Ballast materials and the frequent maintenance of high-speed and heavy-haul railway, the maintenance cost and material consumption become an important problem. Several methods are used to increase the stability and service life of railway structure, also using recycled materials in Ballast Bed construction can be a way for railway sustainable development. Thus, an idea of using furnace slag as the sub-Ballast was put forward in this research. To qualify the performance of furnace slag, a series of tests were carried out, including single particle crushing test, direct shear test, box stiffness test, and the crushed stone which is the traditional sub-Ballast material was used as a comparison. In addition, the test and numerical simulation on box stiffness were carried. Results show that furnace slag has less possible to breakage and abrasion, its shear resistance is 16.46%–19.48% higher, and 20.44%–26.04% decrease in shear dilatancy. However, the stiffness for single particle shows not much difference, the box stiffness test and simulation indicated that furnace slag has a higher capacity and better elasticity. Based on that, this research provides the feasibility of using furnace slag as the sub-Ballast, and it works as an environment-friendly way in railway construction.Railway Engineerin
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Analysis of furnace slag in railway sub-Ballast based on experimental tests and DEM simulations
'Elsevier BV', 2021Co-Authors: Jia W., Markine V.l., Jing GuoqingAbstract:Under the high requirement of Ballast materials and the frequent maintenance of high-speed and heavy-haul railway, the maintenance cost and material consumption become an important problem. Several methods are used to increase the stability and service life of railway structure, also using recycled materials in Ballast Bed construction can be a way for railway sustainable development. Thus, an idea of using furnace slag as the sub-Ballast was put forward in this research. To qualify the performance of furnace slag, a series of tests were carried out, including single particle crushing test, direct shear test, box stiffness test, and the crushed stone which is the traditional sub-Ballast material was used as a comparison. In addition, the test and numerical simulation on box stiffness were carried. Results show that furnace slag has less possible to breakage and abrasion, its shear resistance is 16.46%–19.48% higher, and 20.44%–26.04% decrease in shear dilatancy. However, the stiffness for single particle shows not much difference, the box stiffness test and simulation indicated that furnace slag has a higher capacity and better elasticity. Based on that, this research provides the feasibility of using furnace slag as the sub-Ballast, and it works as an environment-friendly way in railway construction
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Effect of sleeper bottom texture on lateral resistance with discrete element modelling
'Elsevier BV', 2020Co-Authors: Guo Y., Markine V.l., Fu Hao, Yu Qian, Jing GuoqingAbstract:The lateral stability of Ballasted track becomes more important because of the safety requirement under the demand of higher train speed and heavier axle load. To increase the lateral resistance of Ballast Bed, this paper proposes three types of new sleepers, frictional sleepers. The frictional sleepers are sleepers with different shapes of textures attached at the sleeper bottom. To study the application feasibility of the frictional sleepers, experimental tests (single sleeper pull-out test) and numerical simulation (discrete element modelling) are performed. The lateral resistances of the three types of frictional sleepers are compared with the traditional sleeper based on the experimental test, and the mechanism of the lateral resistance increase is revealed according to the numerical simulation. The results indicate that the frictional sleepers can increase the lateral resistance by 32% (maximum), due to the enhanced interaction between sleeper and Ballast particles. More importantly, different types of frictional sleepers have different performances, and the optimal friction sleeper is confirmed. This study is helpful for the further research on sleeper design.
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Effect of sleeper bottom texture on lateral resistance with discrete element modelling
'Elsevier BV', 2020Co-Authors: Guo Y., Markine V.l., Fu Hao, Yu Qian, Jing GuoqingAbstract:The lateral stability of Ballasted track becomes more important because of the safety requirement under the demand of higher train speed and heavier axle load. To increase the lateral resistance of Ballast Bed, this paper proposes three types of new sleepers, frictional sleepers. The frictional sleepers are sleepers with different shapes of textures attached at the sleeper bottom. To study the application feasibility of the frictional sleepers, experimental tests (single sleeper pull-out test) and numerical simulation (discrete element modelling) are performed. The lateral resistances of the three types of frictional sleepers are compared with the traditional sleeper based on the experimental test, and the mechanism of the lateral resistance increase is revealed according to the numerical simulation. The results indicate that the frictional sleepers can increase the lateral resistance by 32% (maximum), due to the enhanced interaction between sleeper and Ballast particles. More importantly, different types of frictional sleepers have different performances, and the optimal friction sleeper is confirmed. This study is helpful for the further research on sleeper design.Accepted Author ManuscriptRailway Engineerin
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Effects of crumb rubber size and percentage on degradation reduction of railway Ballast
'Elsevier BV', 2019Co-Authors: Guo Y., Markine V.l., Qiang Weile, Zhang Hui, Jing GuoqingAbstract:Higher speed, more freight and frequent maintenance increase Ballast degradation and reduce the Ballast lifespan. To reduce Ballast degradation, crumb rubber used as buffering aggregates in Ballast Bed is relatively unexplored and needs more studies, because using it has the advantage of reusing the waster rubber and absorbing the noises. The effects of crumb rubber (CR) size and percentage on Ballast degradation reduction is studied in this paper, and the optimal CR size and percentage are proposed. Three CR size ranges are utilised, i.e., 3 ∼ 5 mm, 10 ∼ 15 mm and 20 ∼ 25 mm, and the percentages are 0, 10, 20 and 30% by weight. Three kinds of Ballast material with two size ranges are utilised. The deteriorated Ballast particles were generated using Los Angeles Abrasion (LAA) tests, and the Ballast degradation was evaluated with the 3D image analysis. The results indicate that Ballast abrasion can be alleviated by adding the CR, while the CR has few influences on the Ballast breakage. When CR size is close to Ballast particle size, the effects of degradation reduction are not obvious. The corner and edge loss are the main types of Ballast abrasion, although different Ballast materials significantly influence the abrasion type and degree. Most importantly, the image analysis method is proved to have the ability to present Ballast degradation process and has great potential for further degradation-related studies.Accepted Author ManuscriptRailway Engineerin
Markine V.l. - One of the best experts on this subject based on the ideXlab platform.
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Analysis of furnace slag in railway sub-Ballast based on experimental tests and DEM simulations
'Elsevier BV', 2021Co-Authors: Jia W., Markine V.l., Jing GuoqingAbstract:Under the high requirement of Ballast materials and the frequent maintenance of high-speed and heavy-haul railway, the maintenance cost and material consumption become an important problem. Several methods are used to increase the stability and service life of railway structure, also using recycled materials in Ballast Bed construction can be a way for railway sustainable development. Thus, an idea of using furnace slag as the sub-Ballast was put forward in this research. To qualify the performance of furnace slag, a series of tests were carried out, including single particle crushing test, direct shear test, box stiffness test, and the crushed stone which is the traditional sub-Ballast material was used as a comparison. In addition, the test and numerical simulation on box stiffness were carried. Results show that furnace slag has less possible to breakage and abrasion, its shear resistance is 16.46%–19.48% higher, and 20.44%–26.04% decrease in shear dilatancy. However, the stiffness for single particle shows not much difference, the box stiffness test and simulation indicated that furnace slag has a higher capacity and better elasticity. Based on that, this research provides the feasibility of using furnace slag as the sub-Ballast, and it works as an environment-friendly way in railway construction
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Analysis of furnace slag in railway sub-Ballast based on experimental tests and DEM simulations
'Elsevier BV', 2021Co-Authors: Jia W., Markine V.l., Jing GuoqingAbstract:Under the high requirement of Ballast materials and the frequent maintenance of high-speed and heavy-haul railway, the maintenance cost and material consumption become an important problem. Several methods are used to increase the stability and service life of railway structure, also using recycled materials in Ballast Bed construction can be a way for railway sustainable development. Thus, an idea of using furnace slag as the sub-Ballast was put forward in this research. To qualify the performance of furnace slag, a series of tests were carried out, including single particle crushing test, direct shear test, box stiffness test, and the crushed stone which is the traditional sub-Ballast material was used as a comparison. In addition, the test and numerical simulation on box stiffness were carried. Results show that furnace slag has less possible to breakage and abrasion, its shear resistance is 16.46%–19.48% higher, and 20.44%–26.04% decrease in shear dilatancy. However, the stiffness for single particle shows not much difference, the box stiffness test and simulation indicated that furnace slag has a higher capacity and better elasticity. Based on that, this research provides the feasibility of using furnace slag as the sub-Ballast, and it works as an environment-friendly way in railway construction.Railway Engineerin
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Effect of sleeper bottom texture on lateral resistance with discrete element modelling
'Elsevier BV', 2020Co-Authors: Guo Y., Markine V.l., Fu Hao, Yu Qian, Jing GuoqingAbstract:The lateral stability of Ballasted track becomes more important because of the safety requirement under the demand of higher train speed and heavier axle load. To increase the lateral resistance of Ballast Bed, this paper proposes three types of new sleepers, frictional sleepers. The frictional sleepers are sleepers with different shapes of textures attached at the sleeper bottom. To study the application feasibility of the frictional sleepers, experimental tests (single sleeper pull-out test) and numerical simulation (discrete element modelling) are performed. The lateral resistances of the three types of frictional sleepers are compared with the traditional sleeper based on the experimental test, and the mechanism of the lateral resistance increase is revealed according to the numerical simulation. The results indicate that the frictional sleepers can increase the lateral resistance by 32% (maximum), due to the enhanced interaction between sleeper and Ballast particles. More importantly, different types of frictional sleepers have different performances, and the optimal friction sleeper is confirmed. This study is helpful for the further research on sleeper design.
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Effect of sleeper bottom texture on lateral resistance with discrete element modelling
'Elsevier BV', 2020Co-Authors: Guo Y., Markine V.l., Fu Hao, Yu Qian, Jing GuoqingAbstract:The lateral stability of Ballasted track becomes more important because of the safety requirement under the demand of higher train speed and heavier axle load. To increase the lateral resistance of Ballast Bed, this paper proposes three types of new sleepers, frictional sleepers. The frictional sleepers are sleepers with different shapes of textures attached at the sleeper bottom. To study the application feasibility of the frictional sleepers, experimental tests (single sleeper pull-out test) and numerical simulation (discrete element modelling) are performed. The lateral resistances of the three types of frictional sleepers are compared with the traditional sleeper based on the experimental test, and the mechanism of the lateral resistance increase is revealed according to the numerical simulation. The results indicate that the frictional sleepers can increase the lateral resistance by 32% (maximum), due to the enhanced interaction between sleeper and Ballast particles. More importantly, different types of frictional sleepers have different performances, and the optimal friction sleeper is confirmed. This study is helpful for the further research on sleeper design.Accepted Author ManuscriptRailway Engineerin
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Image analysis for morphology, rheology and degradation study of railway Ballast: A review
2019Co-Authors: Guo Y., Markine V.l., Zhang X., Qiang Weile, Jing GuoquigAbstract:The performance and deformation of Ballast Bed are significantly influenced by the particle morphology (size and shape), the rheology (translation and rotation), and the degradation (breakage and abrasion). Regarding the Ballast particle morphology, the Ballast particle size is generally measured by sieving and descriBed with the Particle Size Distribution (PSD), while the particle shape is normally classified as three characteristics, the form, angularity, and surface texture. Quantifying particle morphology with current manual methods is difficult to obtain accurate results (often subjective). Concerning the Ballast particle rheology, almost all the related studies are based on numerical simulations, e.g. the Discrete Element Method (DEM). A limited number of studies were performed to record the translation and rotation with the electronic devices emBedded in Ballast layer. However, the numerical simulations can only precisely reflect the Ballast particle rheology in quasi-static tests (e.g. direct shear test), and the electronic devices can only record the Ballast particle rheology in the limited areas, where they were placed. The Ballast breakage could be evaluated by the change of the PSD, but the determination of PSD involves significant errors. Additionally, the manual methods could not fully quantify the Ballast abrasion. As a result, more accurate evaluation methods need to be developed and utilised for the validation and confirmation of the degradation-related studies.Towards these limitations, the studies on two-dimensional (2D) and three-dimensional (3D) image analysis methods for granular materials are reviewed, discussing their existing and potential utilisation in railway Ballast applications. This paper can be of interest to the researchers, who are dealing with the performance and deformation of Ballast Bed. Additionally, a special attention can be paid to utilising the image analysis for accurate particle morphology quantification, particle rheology investigation and Ballast degradation evaluation
Guo Y. - One of the best experts on this subject based on the ideXlab platform.
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Effect of sleeper bottom texture on lateral resistance with discrete element modelling
'Elsevier BV', 2020Co-Authors: Guo Y., Markine V.l., Fu Hao, Yu Qian, Jing GuoqingAbstract:The lateral stability of Ballasted track becomes more important because of the safety requirement under the demand of higher train speed and heavier axle load. To increase the lateral resistance of Ballast Bed, this paper proposes three types of new sleepers, frictional sleepers. The frictional sleepers are sleepers with different shapes of textures attached at the sleeper bottom. To study the application feasibility of the frictional sleepers, experimental tests (single sleeper pull-out test) and numerical simulation (discrete element modelling) are performed. The lateral resistances of the three types of frictional sleepers are compared with the traditional sleeper based on the experimental test, and the mechanism of the lateral resistance increase is revealed according to the numerical simulation. The results indicate that the frictional sleepers can increase the lateral resistance by 32% (maximum), due to the enhanced interaction between sleeper and Ballast particles. More importantly, different types of frictional sleepers have different performances, and the optimal friction sleeper is confirmed. This study is helpful for the further research on sleeper design.
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Effect of sleeper bottom texture on lateral resistance with discrete element modelling
'Elsevier BV', 2020Co-Authors: Guo Y., Markine V.l., Fu Hao, Yu Qian, Jing GuoqingAbstract:The lateral stability of Ballasted track becomes more important because of the safety requirement under the demand of higher train speed and heavier axle load. To increase the lateral resistance of Ballast Bed, this paper proposes three types of new sleepers, frictional sleepers. The frictional sleepers are sleepers with different shapes of textures attached at the sleeper bottom. To study the application feasibility of the frictional sleepers, experimental tests (single sleeper pull-out test) and numerical simulation (discrete element modelling) are performed. The lateral resistances of the three types of frictional sleepers are compared with the traditional sleeper based on the experimental test, and the mechanism of the lateral resistance increase is revealed according to the numerical simulation. The results indicate that the frictional sleepers can increase the lateral resistance by 32% (maximum), due to the enhanced interaction between sleeper and Ballast particles. More importantly, different types of frictional sleepers have different performances, and the optimal friction sleeper is confirmed. This study is helpful for the further research on sleeper design.Accepted Author ManuscriptRailway Engineerin
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Image analysis for morphology, rheology and degradation study of railway Ballast: A review
2019Co-Authors: Guo Y., Markine V.l., Zhang X., Qiang Weile, Jing GuoquigAbstract:The performance and deformation of Ballast Bed are significantly influenced by the particle morphology (size and shape), the rheology (translation and rotation), and the degradation (breakage and abrasion). Regarding the Ballast particle morphology, the Ballast particle size is generally measured by sieving and descriBed with the Particle Size Distribution (PSD), while the particle shape is normally classified as three characteristics, the form, angularity, and surface texture. Quantifying particle morphology with current manual methods is difficult to obtain accurate results (often subjective). Concerning the Ballast particle rheology, almost all the related studies are based on numerical simulations, e.g. the Discrete Element Method (DEM). A limited number of studies were performed to record the translation and rotation with the electronic devices emBedded in Ballast layer. However, the numerical simulations can only precisely reflect the Ballast particle rheology in quasi-static tests (e.g. direct shear test), and the electronic devices can only record the Ballast particle rheology in the limited areas, where they were placed. The Ballast breakage could be evaluated by the change of the PSD, but the determination of PSD involves significant errors. Additionally, the manual methods could not fully quantify the Ballast abrasion. As a result, more accurate evaluation methods need to be developed and utilised for the validation and confirmation of the degradation-related studies.Towards these limitations, the studies on two-dimensional (2D) and three-dimensional (3D) image analysis methods for granular materials are reviewed, discussing their existing and potential utilisation in railway Ballast applications. This paper can be of interest to the researchers, who are dealing with the performance and deformation of Ballast Bed. Additionally, a special attention can be paid to utilising the image analysis for accurate particle morphology quantification, particle rheology investigation and Ballast degradation evaluation
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Image analysis for morphology, rheology and degradation study of railway Ballast: A review
'Elsevier BV', 2019Co-Authors: Guo Y., Markine V.l., Zhang X., Qiang Weile, Jing GuoquigAbstract:The performance and deformation of Ballast Bed are significantly influenced by the particle morphology (size and shape), the rheology (translation and rotation), and the degradation (breakage and abrasion). Regarding the Ballast particle morphology, the Ballast particle size is generally measured by sieving and descriBed with the Particle Size Distribution (PSD), while the particle shape is normally classified as three characteristics, the form, angularity, and surface texture. Quantifying particle morphology with current manual methods is difficult to obtain accurate results (often subjective). Concerning the Ballast particle rheology, almost all the related studies are based on numerical simulations, e.g. the Discrete Element Method (DEM). A limited number of studies were performed to record the translation and rotation with the electronic devices emBedded in Ballast layer. However, the numerical simulations can only precisely reflect the Ballast particle rheology in quasi-static tests (e.g. direct shear test), and the electronic devices can only record the Ballast particle rheology in the limited areas, where they were placed. The Ballast breakage could be evaluated by the change of the PSD, but the determination of PSD involves significant errors. Additionally, the manual methods could not fully quantify the Ballast abrasion. As a result, more accurate evaluation methods need to be developed and utilised for the validation and confirmation of the degradation-related studies.Towards these limitations, the studies on two-dimensional (2D) and three-dimensional (3D) image analysis methods for granular materials are reviewed, discussing their existing and potential utilisation in railway Ballast applications. This paper can be of interest to the researchers, who are dealing with the performance and deformation of Ballast Bed. Additionally, a special attention can be paid to utilising the image analysis for accurate particle morphology quantification, particle rheology investigation and Ballast degradation evaluation.Railway EngineeringGeo-engineerin
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Effects of crumb rubber size and percentage on degradation reduction of railway Ballast
'Elsevier BV', 2019Co-Authors: Guo Y., Markine V.l., Qiang Weile, Zhang Hui, Jing GuoqingAbstract:Higher speed, more freight and frequent maintenance increase Ballast degradation and reduce the Ballast lifespan. To reduce Ballast degradation, crumb rubber used as buffering aggregates in Ballast Bed is relatively unexplored and needs more studies, because using it has the advantage of reusing the waster rubber and absorbing the noises. The effects of crumb rubber (CR) size and percentage on Ballast degradation reduction is studied in this paper, and the optimal CR size and percentage are proposed. Three CR size ranges are utilised, i.e., 3 ∼ 5 mm, 10 ∼ 15 mm and 20 ∼ 25 mm, and the percentages are 0, 10, 20 and 30% by weight. Three kinds of Ballast material with two size ranges are utilised. The deteriorated Ballast particles were generated using Los Angeles Abrasion (LAA) tests, and the Ballast degradation was evaluated with the 3D image analysis. The results indicate that Ballast abrasion can be alleviated by adding the CR, while the CR has few influences on the Ballast breakage. When CR size is close to Ballast particle size, the effects of degradation reduction are not obvious. The corner and edge loss are the main types of Ballast abrasion, although different Ballast materials significantly influence the abrasion type and degree. Most importantly, the image analysis method is proved to have the ability to present Ballast degradation process and has great potential for further degradation-related studies.Accepted Author ManuscriptRailway Engineerin
Yunlong Guo - One of the best experts on this subject based on the ideXlab platform.
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Experimental and numerical investigations on the shear behaviour of recycled railway Ballast
Construction and Building Materials, 2019Co-Authors: Wenli Jia, Yunlong Guo, Valeri Markine, Guoqing JingAbstract:Abstract Ballast degradation is frequently observed under cyclic loading, and results in bearing capacity and drainage problem of Ballast track. To keep the stability and safety, periodical maintenances are needed, such as cleaning and replacement, which produce a huge amount of wasted Ballast. Thus, reusing the deteriorated Ballast can become a considerable method for sustainable railway development and environment protection. One applications is adding the cleaned deteriorated Ballast (i.e. recycled Ballast) into fresh Ballast. Furthermore, it is common situation that applying the mixture of fresh and deteriorated Ballast during the railway operation. To study the mechanical behaviour of this mixture and find out the criterion weight proportion of the recycled Ballast, a series of large direct shear tests were performed with different weight proportions (0%, 10%, 20%, 30%, 40%, and 50%) of recycled Ballast mixed into fresh Ballast under different normal stresses (50, 100 and 200 kPa). In addition, a numerical simulation based on discrete element method (DEM) was used to illustrate the shear strength, contact forces, coordination numbers and displacements of Ballast particles. Results show that the shear strength reduction of the mixture is insignificant, when mixed with less than 30% recycled Ballast. With the recycled Ballast proportion increasing, the shear strength and coordination number reduce and the displacements get larger. This research provides a foundation for the application of recycled Ballast, and on the other hands, adding fresh Ballast can be a solution to reinforce deteriorated Ballast Bed.
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Ballast degradation effect of particle size and shape using los angeles abrasion test and image analysis
Construction and Building Materials, 2018Co-Authors: Yunlong Guo, V L Markine, Jianing Song, Guoqing JingAbstract:Ballast track is the most widely used track for the railway transport, and Ballast Bed plays a significant role to provide resistances during train operation. Generally, the Ballast Bed consists of crushed stones. To achieve the mitigation of Ballast degradation, the first priority is to describe the degradation development and to study its effect factors. The influence of Ballast morphology (particle size and shape) on Ballast degradation is examined here using the Los Angeles Abrasion (LAA) test in combination with 3-D image analysis. LAA tests are used to obtain the deteriorated Ballast. Then, based on the 3-D images, the changes of Ballast particles after the tests were analysed. To quantify the Ballast degradation (abrasion and breakage), the Abrasion Depth based on the analysis of 3-D images were proposed, while Ballast breakage was estimated using the broken particles ratio. The results have shown that Ballast degradation is directly related to the Ballast morphology. The proposed image-based procedure can effectively be applied to assess Ballast degradation. The results can be used for Ballast material standardization, modelling of Ballast degradation process and maintenance cycle prediction.
