Purpose – This study aims to analyze the factors, evaluation techniques of the durability of existing railwayengineering.Design/methodology/approach – China has built a railway network of over 150,000 km. Ensuring t...Purpose – This study aims to analyze the factors, evaluation techniques of the durability of existing railwayengineering.Design/methodology/approach – China has built a railway network of over 150,000 km. Ensuring thesafety of the existing railway engineering is of great significance for maintaining normal railway operationorder. However, railway engineering is a strip structure that crosses multiple complex environments. Andrailway engineering will withstand high-frequency impact loads from trains. The above factors have led todifferences in the deterioration characteristics and maintenance strategies of railway engineering compared toconventional concrete structures. Therefore, it is very important to analyze the key factors that affect thedurability of railway structures and propose technologies for durability evaluation.Findings – The factors that affect the durability and reliability of railway engineering are mainly divided intothree categories: material factors, environmental factors and load factors. Among them, material factors alsoinclude influencing factors, such as raw materials, mix proportions and so on. Environmental factors varydepending on the service environment of railway engineering, and the durability and deterioration of concretehave different failure mechanisms. Load factors include static load and train dynamic load. The on-site rapiddetection methods for five common diseases in railway engineering are also proposed in this paper. Thesemethods can quickly evaluate the durability of existing railway engineering concrete.Originality/value – The research can provide some new evaluation techniques and methods for thedurability of existing railway engineering.展开更多
At present,rail transit is developing rapidly in the world,and this means new and changing requirements for the training of talents in railway engineering experiments.Given the current problems of limited laboratory/f...At present,rail transit is developing rapidly in the world,and this means new and changing requirements for the training of talents in railway engineering experiments.Given the current problems of limited laboratory/field instruments for railway engineering experimentsand the safety/administrative difficulties of going to the frontline of railway lines to teach railway engineering experiemnts in the field,the Department of Railway Engineering of Central South University tried to introduce virtual reality(VR)technology to teach students experiments in the field of railway engineering.Through the virtualized experimental methods,students can carry out railway engineering experiments such as;vehicle wheel pair off-axis experiments,track geometry and position detection,etc.by immersive means.It was observed that after performing virtual simulation experiments,students appeared conversant in subsequent field experiments.Thus,VR greatly improves the teaching efficiency of railway engineering experiments.展开更多
In view of the problems of inconsistent data semantics,inconsistent data formats,and difficult data quality assurance between the railway engineering design phase and the construction and operation phase,as well as th...In view of the problems of inconsistent data semantics,inconsistent data formats,and difficult data quality assurance between the railway engineering design phase and the construction and operation phase,as well as the difficulty in fully realizing the value of design results,this paper proposes a design and implementation scheme for a railway engineering collaborative design platform.The railway engineering collaborative design platform mainly includes functional modules such as metadata management,design collaboration,design delivery management,model component library,model rendering services,and Building Information Modeling(BIM)application services.Based on this,research is conducted on multi-disciplinary parameterized collaborative design technology for railway engineering,infrastructure data management and delivery technology,and design multi-source data fusion and application technology.The railway engineering collaborative design platform is compared with other railway design software to further validate its advantages and advanced features.The platform has been widely applied in multiple railway construction projects,greatly improving the design and project management efficiency.展开更多
German engineer Heinrich Hildebrand came to China as a spy in 1891,serving at the German Embassy in Beijing and collecting Chinese railway information.In 1892,he began to work for Zhang Zhidong and participated in the...German engineer Heinrich Hildebrand came to China as a spy in 1891,serving at the German Embassy in Beijing and collecting Chinese railway information.In 1892,he began to work for Zhang Zhidong and participated in the construction of the Daye railway and Hanyang Iron Works,among other projects.Recommended by Zhang Zhidong,he was appointed as counselor of the China Railway Company by Sheng Xuanhuai.After Germany took Jiaozhou Bay in 1897,Hildebrand presided over the survey and construction of the Shandong Railway.He served as its General Director and chief engineer for ten years,which was the most important period of his career.As his identity switched from German spy in Zhang Zhidong’s staff to General Director of the Shandong Railway,his colonialist mentality gradually came to the fore,and he took a tough stance when dealing with Chinese officials and workers.He was highly appreciated by Zhang Zhidong and strongly opposed by Yuan Shikai.Western engineers in early modern China played a dual role in the course of China’s modernization.On the one hand,they promoted the cause of China’s modernization as professionals,and on the other hand,they often became spokesmen for and active agents of imperialism.展开更多
The railway engineering major shows extremely strong applicability,with the internationalization of railway engineering teaching and communication,how to solve the problem of cultivating the international students of ...The railway engineering major shows extremely strong applicability,with the internationalization of railway engineering teaching and communication,how to solve the problem of cultivating the international students of the railway engineering major experimental teaching is a core problem that the railway engineering majors in universities need to solve at this stage.Through reform,a new type of experimental teaching system for railway engineering specialty was constructed,that is,the experimental course system and content system determined by the international students training program were taken as the core,the construction of teachers,experimental facilities,practice bases and other conditions as the basis,and the system construction and operation organization to build an organic whole composed of four elements for guarantee.It is closely integrated with the theoretical teaching system and relatively independent.It guarantees the realization of the goal of international students training.And it can integrate and optimize the experimental teaching links,content,methods and evaluation system,and build a“gradual experimentprofessional experiment-comprehensive experiment”progressive gradient experiment teaching system.Form a benign pattern of collaborative training of laboratories,practice bases and scientific research bases,mutual promotion of teaching and scientific research,and effectively promote the improvement of students’experimental innovation ability.展开更多
Virtual simulation teaching is an addendum to the experimental teaching mode of railway engineering,and the two teaching methods complement each other and merge with each other.In view of the current research,there is...Virtual simulation teaching is an addendum to the experimental teaching mode of railway engineering,and the two teaching methods complement each other and merge with each other.In view of the current research,there is little discussion about the integration path of the two above.Based on the connotation and design of virtual simulation teaching,this research systematically expounds the integration of the real path and path optimization problems,and puts forward the railway engineering experimental teaching principles based on virtual simulation teaching.On the basis of this research,a virtual simulation experiment platform for vibration mechanics and its application in the floating slab vibration damping track was developed to make full use of three-dimensional modeling,virtual reality,human-computer interaction and other technologies,which can realistically simulate the vibration law and vibration damping effect of the rail transit system,and in the hope that the virtual simulation teaching can be widely used in the experimental teaching mode of railway engineering in the future.展开更多
Intelligent construction technology has been widely used in the field of railway engineering.This work first analyzes the connotation,function,and characteristics of intelligent construction of railway engineering(ICR...Intelligent construction technology has been widely used in the field of railway engineering.This work first analyzes the connotation,function,and characteristics of intelligent construction of railway engineering(ICRE)and establishes its system structure from three dimensions,namely,life cycle,layers of management,and intelligent function,to deeply understand the development situation of intelligent railway construction in China.Second,seven key technical support systems of ICRE,which include building information modeling(BIM)standard system for China’s railway sector,technology management platform and life cycle management based on BIM-hGIS(geography information system),ubiquitous intelligent perception system,intelligent Intemet-of-Things(IoT)communication system based on mobile interconnection,construction management platform based on cloud computing and big data,unmanned operation system based on artificial intelligence,intelligent machinery and robot,and intelligent operation and maintenance system based on BIM and PHM(prediction and health management),are established.Third,ICRE is divided into three development stages:primary(perception),intermediate(substitution),and advanced(intelligence).The evaluation index system of each stage is provided from the aspects of technology and function.Finally,this work summarizes and analyzes the application situation of ICRE in the entire railway sector of China,represented by Beijing-Zhangjiakou and Beijing-Xiong’an high-speed railways.Result shows that the technical support systems of the ICRE have emerged in China and are still in the process of deepening basic technology research and preliminary application.In the future,the ICRE of China’s railway sector will develop toward a higher stage.展开更多
The planned Yunnan-Tibet railway goes through the northwest of Yunnan Province and the southeast of the Tibet Autonomous Region. Because of its location near the collision belt of the Eurasian and Indian plates, compl...The planned Yunnan-Tibet railway goes through the northwest of Yunnan Province and the southeast of the Tibet Autonomous Region. Because of its location near the collision belt of the Eurasian and Indian plates, complex engineering geological conditions and difficult engineering geological problems are encountered. The study is aimed at making the zoning assessment of crustal stability along the railway line so as to provide a better base for its construction, especially its line selection. For this purpose, the following seven influencing factors of crustal stability were selected and quantified by grading and scoring： active fault, seismic activity, geo-stress field, geo-strain field, geothermal field, geo-hazard, and lithologic character. Of these factors, the active fault, seismic activity and geo-hazard are the three most prominent factors influencing the railway construction. Along the railway line there are 1731703 calculation units to be divided. The zoning assessment calculation was completed by ArcGIS-based information fusion method. The assessment results aid railway line selection and show that there are 10 stable sectors, 28 relatively stable sectors, 23 relatively unstable sectors, and 20 unstable sectors along the Yunnan-Tibet railway line.展开更多
At present,BIM platforms rely on foreign software.Homemade software and industry applications are mostly secondary developments,which present stranglehold problems caused by interruptions to the software supply.To sol...At present,BIM platforms rely on foreign software.Homemade software and industry applications are mostly secondary developments,which present stranglehold problems caused by interruptions to the software supply.To solve the problem,key technical research on the 3D integrated design of railway engineering was stuedied based on homemade graphics engines to propose an innovative railway BIM platform framework.The entire process was completed from the top-level design to the engineering verification of the platform.The co-designed mechanism of a"center model and link"hybrid mode was constructed,which solved the difficulties of data management and increment synchronization at a large scale,achieving teamwork among surveying and mapping,alignments,and bridges.The results of this study could provide strong support for the development of BIM software for a whole railway and all majors.展开更多
This paper develops a dual-indicator discrete method(DDM)for evaluating the system reliability performance of long soil subgrade slopes.First,they are segmented into many slope sections using the random finite element...This paper develops a dual-indicator discrete method(DDM)for evaluating the system reliability performance of long soil subgrade slopes.First,they are segmented into many slope sections using the random finite element method,to ensure each section statistically contains one potential local instability.Then,the k-out-of-n system model is used to describe the relationship between the total number of sections n,the acceptable number of failure sections m,the reliability of sections R_(sec),and the system reliability R_(sys).Finally,m and R_(sys)are jointly used to assess the system reliability performance.For cases lacking spatial data of soil properties,a simplified DDM is provided in which long subgrade slopes are segmented by the empirical value of section length and R_(sec)is substituted by that of crosssections taken from them.The results show that(1)DDM can provide the probability that the actual number of local instabilities does not exceed a desired threshold.(2)R_(sys)decreases with increasing n or decreasing R_(sec);that is,it is likely to encounter more local instabilities for longer or weaker subgrade slopes.n is negatively related to the horizontal scale of fluctuation of soil properties and positively related to the total length of subgrade slopes L.(3)When L is sufficiently large,there is a considerable opportunity to meet local instabilities even if R_(sec)is large enough.展开更多
The construction contract can control the implementation of the whole project. The effective conclusion and management of construction contracts will directly affect the interests of both parties to the contract, and ...The construction contract can control the implementation of the whole project. The effective conclusion and management of construction contracts will directly affect the interests of both parties to the contract, and even affect the timely completion of the project. Therefore, railway construction contract management is not only an important part of enterprise management, but also the core of railway project implementation management. Specifically, the objectives of railway project management include two aspects: Firstly, the cost, duration and quality objectives of the project and the need for a corresponding contractual basis for control. Secondly, the results of contract formation, execution and management are directly related to the efficiency and social reputation of the enterprise. Therefore, strengthening contract management and internal risk control requires effective risk management models and countermeasures, which are crucial to avoid or reduce corporate risks, improve project quality and reasonably reduce transportation costs.展开更多
With the rapid development of the society, the development of the railway transportation industry is accelerating. Many places have begun to expand the railway, which can not only bring greater convenience to the tran...With the rapid development of the society, the development of the railway transportation industry is accelerating. Many places have begun to expand the railway, which can not only bring greater convenience to the transportation, but also to speed up the communication between regions. For the current development of railway transportation industry, railway construction can promote the development of transportation industry to a large extent, it is necessary to pay attention to ensure the stability and safety of railway construction. At present, there are some problems of maintenance quality in some railway engineering lines, which affect the operation utility of railway. This paper analyzes the factors endangering the safety of railway engineering lines and the existing maintenance problems, and puts forward the corresponding maintenance measures to improve the overall quality of railway.展开更多
Rolling stock manufacturers are finding structural solutions to reduce power required by the vehicles,and the lightweight design of the car body represents a possible solution.Optimization processes and innovative mat...Rolling stock manufacturers are finding structural solutions to reduce power required by the vehicles,and the lightweight design of the car body represents a possible solution.Optimization processes and innovative materials can be combined in order to achieve this goal.In this framework,we propose the redesign and optimization process of the car body roof for a light rail vehicle,introducing a sandwich structure.Bonded joint was used as a fastening system.The project was carried out on a single car of a modern tram platform.This preliminary numerical work was developed in two main steps:redesign of the car body structure and optimization of the innovated system.Objective of the process was the mass reduction of the whole metallic structure,while the constraint condition was imposed on the first frequency of vibration of the system.The effect of introducing a sandwich panel within the roof assembly was evaluated,focusing on the mechanical and dynamic performances of the whole car body.A mass saving of 63%on the optimized components was achieved,corresponding to a 7.6%if compared to the complete car body shell.In addition,a positive increasing of 17.7%on the first frequency of vibration was observed.Encouraging results have been achieved in terms of weight reduction and mechanical behaviour of the innovated car body.展开更多
In the realm of high-speed railway bridge engineering,managing the intricacies of the track-bridge system model(TBSM)during seismic events remains a formidable challenge.This study pioneers an innovative approach by p...In the realm of high-speed railway bridge engineering,managing the intricacies of the track-bridge system model(TBSM)during seismic events remains a formidable challenge.This study pioneers an innovative approach by presenting a simplified bridge model(SBM)optimized for both computational efficiency and precise representation,a seminal contribution to the engineering design landscape.Central to this innovation is a novel model-updating methodology that synergistically melds artificial neural networks with an augmented particle swarm optimization.The neural networks adeptly map update parameters to seismic responses,while enhancements to the particle swarm algorithm’s inertial and learning weights lead to superior SBM parameter updates.Verification via a 4-span high-speed railway bridge revealed that the optimized SBM and TBSM exhibit a highly consistent structural natural period and seismic response,with errors controlled within 7%.Additionally,the computational efficiency improved by over 100%.Leveraging the peak displacement and shear force residuals from the seismic TBSM and SBM as optimization objectives,SBM parameters are adeptly revised.Furthermore,the incorporation of elastoplastic springs at the beam ends of the simplified model effectively captures the additional mass,stiffness,and constraint effects exerted by the track system on the bridge structure.展开更多
A new mechanics model, which reveals additional longitudinal force transmission between the continuously welded rails and the bridges, is established on the fact that the influence of the mutual relative displacement ...A new mechanics model, which reveals additional longitudinal force transmission between the continuously welded rails and the bridges, is established on the fact that the influence of the mutual relative displacement (among) the rail, the sleeper and the beam is taken into account. An example is presented and numerical results are compared. The results show that the additional longitudinal forces calculated with the new model are less than those of the previous, especially in the case of the flexible pier bridges. The new model is also suitable for the analysis of the additional longitudinal force transmission between rails and bridges of ballastless track with small resistance fasteners without taking the sleeper displacement into account, and compared with the ballast bridges, the ballastless bridges have a much stronger additional longitudinal force transmission between the continuously welded rails and the bridges.展开更多
Deep mixed column （DMC） is known as one of the effective methods for stabilizing the natural earth beneath road or railway embankments to control stability and settlements under traffic loads. The load distribution ...Deep mixed column （DMC） is known as one of the effective methods for stabilizing the natural earth beneath road or railway embankments to control stability and settlements under traffic loads. The load distribution mechanism of embankment overlying on loose subgrades stabilized with DMCs considerably depends on the columns＇ mechanical and geometrical specifications. The present study uses the laboratory investigation to understand the behavior of embankments lying on loose sandy subgrade in three different conditions： （1） subgrade without reinforcement, （2） subgrade reinforced with DMCs in a triangular pattern and horizontal plan, and （3） subgrade reinforced with DMCs in a square pattern and horizontal plan. For this purpose, by adopting the scale factor of 1：10, a reference embankment with 20 cm height, 250 cm length, and 93% maximum dry density achieved in standard Proctor compaction test was constructed over a 70 cm thick loose sandy bed with the relative density of 50% in a loading chamber, and its load-displacement behavior was evaluated until the failure occurred. In the next two tests, DMCs （with 10 cm diameter, 40 cm length, and 25 cm center-to-center spacing） were placed in groups in two different patterns （square and triangular） in the same sandy bed beneath the embankment and, consequently, the embankments were constructed over the reinforced subgrades and gradually loaded until the failure happened. In all the three tests, the load-displacement behaviors of the embankment and the selected DMCs were instrumented for monitoring purpose. The obtained results implied 64% increase in failure load and 40% decrease in embankment crest settlement when using the square pattern of DMCs compared with those of the reference embankment, while these values were 63% and 12%, respectively, for DMCs in triangular pattern. This confirmed generally better performance of DMCs with a triangular pattern.展开更多
In this work,a method is put forward to obtain the dynamic solution efficiently and accurately for a large-scale train-track-substructure(TTS)system.It is called implicit-explicit integration and multi-time-step solut...In this work,a method is put forward to obtain the dynamic solution efficiently and accurately for a large-scale train-track-substructure(TTS)system.It is called implicit-explicit integration and multi-time-step solution method(abbreviated as mI-nE-MTS method).The TTS system is divided into train-track subsystem and substruc-ture subsystem.Considering that the root cause of low effi-ciency of obtaining TTS solution lies in solving the alge-braic equation of the substructures,the high-efficient Zhai method,an explicit integration scheme,can be introduced to avoid matrix inversion process.The train-track system is solved by implicitly Park method.Moreover,it is known that the requirement of time step size differs for different sub-systems,integration methods and structural frequency response characteristics.A multi-time-step solution is pro-posed,in which time step size for the train-track subsystem and the substructure subsystem can be arbitrarily chosen once satisfying stability and precision demand,namely the time spent for m implicit integral steps is equal to n explicit integral steps,i.e.,mI=nE as mentioned above.The numeri-cal examples show the accuracy,efficiency,and engineering practicality of the proposed method.展开更多
Interlayer soil in railway substructures is characterized by a fine/coarse soil mixture.Considering that the resilient modulus M_(r) of the mixture is influenced by the microstructure of fine soil,it is worthwhile to ...Interlayer soil in railway substructures is characterized by a fine/coarse soil mixture.Considering that the resilient modulus M_(r) of the mixture is influenced by the microstructure of fine soil,it is worthwhile to investigate this aspect further.In this study,the microstructure of fines was explored by mercury intrusion porosimetry(MIP),and its influence on the M_(r) of the mixture was studied by multi-stage dynamic triaxial tests with varying deviator stress amplitudesσ_(d).The results showed a fine matrix fabric obtained at water contents of fine soil w_(f)=17.6%and 13.7%(>the plastic limit of fine soil w_(p)=12%),and a fine aggregate fabric identified at w_(f)=10.6%(<w_(p)=12%).Interestingly,the influences of w_(f) andσ_(d) on the M_(r) of the mixture were observed:the rise inσ_(d) contributed to a decline in M_(r) when w_(f)>w_(p) but to an increase in M_(r) when w_(f)<w_(p).It was concluded that,for the fine matrix fabric(w_(f)>w_(p)),increasingσ_(d) induced a reduction in M_(r),while for the fine aggregate fabric(w_(f)<w_(p)),increasingσ_(d) gave rise to the growth of M_(r).The distinct M_(r)-σ_(d) behaviors for these two fabrics were explained by the competing influences between soil hardening upon loading and soil rebounding upon unloading.For the fine matrix fabric(w_(f)>w_(p)),considering its high deformability,the rebounding effect on M_(r) outweighed the hardening effect,and thus a decline in M_(r) occurred with the growth ofσ_(d).Conversely,for the fine aggregate fabric(w_(f)<w_(p)),the rebounding effect on M_(r) was secondary compared with the hardening effect based on the consideration of its low deformability,and thus an increase in M_(r) was observed with risingσ_(d).展开更多
By building the finite element model, the track parameters, including the ultimate longitudinal resistance, the length of the intermediate straight line, and the gap between spacer blocks, were analyzed for their infl...By building the finite element model, the track parameters, including the ultimate longitudinal resistance, the length of the intermediate straight line, and the gap between spacer blocks, were analyzed for their influences on the longitudinal forces and displacements of the single turnout and turnout group, respectively. The results indicate that when the longitudinal resistance drops from 32 to 20 N/cm, the maximum additional longitudinal force of the turnout group increases by 19. 2%, and the maximum additional longitudinal displacement of the turnout group grows by 85.3% compared with 50.4% for the single turnout. When the length of intermediate straight line rises from 0 m to infinite, the maximum additional longitudinal force decreases by 38.8%, and the maximum additional longitudinal displacement by 80.3%.展开更多
In recent years,with the development of road and railway transportation industries,a variety of complicated decisionmaking problems have emerged in real-world applications.It is urgent to analyze these problems from t...In recent years,with the development of road and railway transportation industries,a variety of complicated decisionmaking problems have emerged in real-world applications.It is urgent to analyze these problems from the perspective of theoretical and methodological innovations,and provide methods in management,decision-making and application so as to achieve efficient operations of traffic and transportation systems.These problems have展开更多
基金funded by the National Key Research and Development Program of China(No:2020YFC1909900)the National Natural Science Foundation of China(No:51908550)the Scientific Research Project of China Academy of Railway Sciences Group Corporation Limited(No:2021YJ173).
文摘Purpose – This study aims to analyze the factors, evaluation techniques of the durability of existing railwayengineering.Design/methodology/approach – China has built a railway network of over 150,000 km. Ensuring thesafety of the existing railway engineering is of great significance for maintaining normal railway operationorder. However, railway engineering is a strip structure that crosses multiple complex environments. Andrailway engineering will withstand high-frequency impact loads from trains. The above factors have led todifferences in the deterioration characteristics and maintenance strategies of railway engineering compared toconventional concrete structures. Therefore, it is very important to analyze the key factors that affect thedurability of railway structures and propose technologies for durability evaluation.Findings – The factors that affect the durability and reliability of railway engineering are mainly divided intothree categories: material factors, environmental factors and load factors. Among them, material factors alsoinclude influencing factors, such as raw materials, mix proportions and so on. Environmental factors varydepending on the service environment of railway engineering, and the durability and deterioration of concretehave different failure mechanisms. Load factors include static load and train dynamic load. The on-site rapiddetection methods for five common diseases in railway engineering are also proposed in this paper. Thesemethods can quickly evaluate the durability of existing railway engineering concrete.Originality/value – The research can provide some new evaluation techniques and methods for thedurability of existing railway engineering.
基金Education and Teaching Reform Project of Central South University(2019jy097).
文摘At present,rail transit is developing rapidly in the world,and this means new and changing requirements for the training of talents in railway engineering experiments.Given the current problems of limited laboratory/field instruments for railway engineering experimentsand the safety/administrative difficulties of going to the frontline of railway lines to teach railway engineering experiemnts in the field,the Department of Railway Engineering of Central South University tried to introduce virtual reality(VR)technology to teach students experiments in the field of railway engineering.Through the virtualized experimental methods,students can carry out railway engineering experiments such as;vehicle wheel pair off-axis experiments,track geometry and position detection,etc.by immersive means.It was observed that after performing virtual simulation experiments,students appeared conversant in subsequent field experiments.Thus,VR greatly improves the teaching efficiency of railway engineering experiments.
基金supported by the National Key Research and Development Program of China(2021YFB2600405).
文摘In view of the problems of inconsistent data semantics,inconsistent data formats,and difficult data quality assurance between the railway engineering design phase and the construction and operation phase,as well as the difficulty in fully realizing the value of design results,this paper proposes a design and implementation scheme for a railway engineering collaborative design platform.The railway engineering collaborative design platform mainly includes functional modules such as metadata management,design collaboration,design delivery management,model component library,model rendering services,and Building Information Modeling(BIM)application services.Based on this,research is conducted on multi-disciplinary parameterized collaborative design technology for railway engineering,infrastructure data management and delivery technology,and design multi-source data fusion and application technology.The railway engineering collaborative design platform is compared with other railway design software to further validate its advantages and advanced features.The platform has been widely applied in multiple railway construction projects,greatly improving the design and project management efficiency.
基金funded by a Knowledge Innovation Project of the Chinese Academy of Sciences,“Comparative Study of Science and Technology between China and Foreign Countries”(GZ01-07-01).
文摘German engineer Heinrich Hildebrand came to China as a spy in 1891,serving at the German Embassy in Beijing and collecting Chinese railway information.In 1892,he began to work for Zhang Zhidong and participated in the construction of the Daye railway and Hanyang Iron Works,among other projects.Recommended by Zhang Zhidong,he was appointed as counselor of the China Railway Company by Sheng Xuanhuai.After Germany took Jiaozhou Bay in 1897,Hildebrand presided over the survey and construction of the Shandong Railway.He served as its General Director and chief engineer for ten years,which was the most important period of his career.As his identity switched from German spy in Zhang Zhidong’s staff to General Director of the Shandong Railway,his colonialist mentality gradually came to the fore,and he took a tough stance when dealing with Chinese officials and workers.He was highly appreciated by Zhang Zhidong and strongly opposed by Yuan Shikai.Western engineers in early modern China played a dual role in the course of China’s modernization.On the one hand,they promoted the cause of China’s modernization as professionals,and on the other hand,they often became spokesmen for and active agents of imperialism.
文摘The railway engineering major shows extremely strong applicability,with the internationalization of railway engineering teaching and communication,how to solve the problem of cultivating the international students of the railway engineering major experimental teaching is a core problem that the railway engineering majors in universities need to solve at this stage.Through reform,a new type of experimental teaching system for railway engineering specialty was constructed,that is,the experimental course system and content system determined by the international students training program were taken as the core,the construction of teachers,experimental facilities,practice bases and other conditions as the basis,and the system construction and operation organization to build an organic whole composed of four elements for guarantee.It is closely integrated with the theoretical teaching system and relatively independent.It guarantees the realization of the goal of international students training.And it can integrate and optimize the experimental teaching links,content,methods and evaluation system,and build a“gradual experimentprofessional experiment-comprehensive experiment”progressive gradient experiment teaching system.Form a benign pattern of collaborative training of laboratories,practice bases and scientific research bases,mutual promotion of teaching and scientific research,and effectively promote the improvement of students’experimental innovation ability.
基金The research is financially supported by First-class Undergraduate Course Funding Project in Hunan Province-Virtual Simulation Experimental Teaching Course(Xiang Jiao Tong[2021]No.28),Hunan Engineering Teaching Team)(Xiang Jiao Tong[2019]No.370)National Experimental Teaching Center of Civil Engineering Virtual Simulation(Central South University)Open Project(202001)Education and Teaching Reform Project of Central South University(2020jy063),which is gratefully acknowledged by the authors.
文摘Virtual simulation teaching is an addendum to the experimental teaching mode of railway engineering,and the two teaching methods complement each other and merge with each other.In view of the current research,there is little discussion about the integration path of the two above.Based on the connotation and design of virtual simulation teaching,this research systematically expounds the integration of the real path and path optimization problems,and puts forward the railway engineering experimental teaching principles based on virtual simulation teaching.On the basis of this research,a virtual simulation experiment platform for vibration mechanics and its application in the floating slab vibration damping track was developed to make full use of three-dimensional modeling,virtual reality,human-computer interaction and other technologies,which can realistically simulate the vibration law and vibration damping effect of the rail transit system,and in the hope that the virtual simulation teaching can be widely used in the experimental teaching mode of railway engineering in the future.
文摘Intelligent construction technology has been widely used in the field of railway engineering.This work first analyzes the connotation,function,and characteristics of intelligent construction of railway engineering(ICRE)and establishes its system structure from three dimensions,namely,life cycle,layers of management,and intelligent function,to deeply understand the development situation of intelligent railway construction in China.Second,seven key technical support systems of ICRE,which include building information modeling(BIM)standard system for China’s railway sector,technology management platform and life cycle management based on BIM-hGIS(geography information system),ubiquitous intelligent perception system,intelligent Intemet-of-Things(IoT)communication system based on mobile interconnection,construction management platform based on cloud computing and big data,unmanned operation system based on artificial intelligence,intelligent machinery and robot,and intelligent operation and maintenance system based on BIM and PHM(prediction and health management),are established.Third,ICRE is divided into three development stages:primary(perception),intermediate(substitution),and advanced(intelligence).The evaluation index system of each stage is provided from the aspects of technology and function.Finally,this work summarizes and analyzes the application situation of ICRE in the entire railway sector of China,represented by Beijing-Zhangjiakou and Beijing-Xiong’an high-speed railways.Result shows that the technical support systems of the ICRE have emerged in China and are still in the process of deepening basic technology research and preliminary application.In the future,the ICRE of China’s railway sector will develop toward a higher stage.
基金supported by the Special Project of Basic Work of Science and Technology(grant No. 2011FY110100)the Geological Survey of the Ministry of Land and Resources(grant No.1212010541404)the Project of the 12th Five-year National Sci-Tech Support Plan(grant No.2011BAK12B09)
文摘The planned Yunnan-Tibet railway goes through the northwest of Yunnan Province and the southeast of the Tibet Autonomous Region. Because of its location near the collision belt of the Eurasian and Indian plates, complex engineering geological conditions and difficult engineering geological problems are encountered. The study is aimed at making the zoning assessment of crustal stability along the railway line so as to provide a better base for its construction, especially its line selection. For this purpose, the following seven influencing factors of crustal stability were selected and quantified by grading and scoring： active fault, seismic activity, geo-stress field, geo-strain field, geothermal field, geo-hazard, and lithologic character. Of these factors, the active fault, seismic activity and geo-hazard are the three most prominent factors influencing the railway construction. Along the railway line there are 1731703 calculation units to be divided. The zoning assessment calculation was completed by ArcGIS-based information fusion method. The assessment results aid railway line selection and show that there are 10 stable sectors, 28 relatively stable sectors, 23 relatively unstable sectors, and 20 unstable sectors along the Yunnan-Tibet railway line.
基金supported in part by CHN RAILWAY(Grant Number L2021G012)in part by CHN NSFC under(Grant U2268203).
文摘At present,BIM platforms rely on foreign software.Homemade software and industry applications are mostly secondary developments,which present stranglehold problems caused by interruptions to the software supply.To solve the problem,key technical research on the 3D integrated design of railway engineering was stuedied based on homemade graphics engines to propose an innovative railway BIM platform framework.The entire process was completed from the top-level design to the engineering verification of the platform.The co-designed mechanism of a"center model and link"hybrid mode was constructed,which solved the difficulties of data management and increment synchronization at a large scale,achieving teamwork among surveying and mapping,alignments,and bridges.The results of this study could provide strong support for the development of BIM software for a whole railway and all majors.
基金supported by the National Natural Science Foundation of China(Nos.52078435 and 51878560)the financial support from the open research fund of MOE Key Laboratory of High-Speed Railway Engineering。
文摘This paper develops a dual-indicator discrete method(DDM)for evaluating the system reliability performance of long soil subgrade slopes.First,they are segmented into many slope sections using the random finite element method,to ensure each section statistically contains one potential local instability.Then,the k-out-of-n system model is used to describe the relationship between the total number of sections n,the acceptable number of failure sections m,the reliability of sections R_(sec),and the system reliability R_(sys).Finally,m and R_(sys)are jointly used to assess the system reliability performance.For cases lacking spatial data of soil properties,a simplified DDM is provided in which long subgrade slopes are segmented by the empirical value of section length and R_(sec)is substituted by that of crosssections taken from them.The results show that(1)DDM can provide the probability that the actual number of local instabilities does not exceed a desired threshold.(2)R_(sys)decreases with increasing n or decreasing R_(sec);that is,it is likely to encounter more local instabilities for longer or weaker subgrade slopes.n is negatively related to the horizontal scale of fluctuation of soil properties and positively related to the total length of subgrade slopes L.(3)When L is sufficiently large,there is a considerable opportunity to meet local instabilities even if R_(sec)is large enough.
文摘The construction contract can control the implementation of the whole project. The effective conclusion and management of construction contracts will directly affect the interests of both parties to the contract, and even affect the timely completion of the project. Therefore, railway construction contract management is not only an important part of enterprise management, but also the core of railway project implementation management. Specifically, the objectives of railway project management include two aspects: Firstly, the cost, duration and quality objectives of the project and the need for a corresponding contractual basis for control. Secondly, the results of contract formation, execution and management are directly related to the efficiency and social reputation of the enterprise. Therefore, strengthening contract management and internal risk control requires effective risk management models and countermeasures, which are crucial to avoid or reduce corporate risks, improve project quality and reasonably reduce transportation costs.
文摘With the rapid development of the society, the development of the railway transportation industry is accelerating. Many places have begun to expand the railway, which can not only bring greater convenience to the transportation, but also to speed up the communication between regions. For the current development of railway transportation industry, railway construction can promote the development of transportation industry to a large extent, it is necessary to pay attention to ensure the stability and safety of railway construction. At present, there are some problems of maintenance quality in some railway engineering lines, which affect the operation utility of railway. This paper analyzes the factors endangering the safety of railway engineering lines and the existing maintenance problems, and puts forward the corresponding maintenance measures to improve the overall quality of railway.
文摘Rolling stock manufacturers are finding structural solutions to reduce power required by the vehicles,and the lightweight design of the car body represents a possible solution.Optimization processes and innovative materials can be combined in order to achieve this goal.In this framework,we propose the redesign and optimization process of the car body roof for a light rail vehicle,introducing a sandwich structure.Bonded joint was used as a fastening system.The project was carried out on a single car of a modern tram platform.This preliminary numerical work was developed in two main steps:redesign of the car body structure and optimization of the innovated system.Objective of the process was the mass reduction of the whole metallic structure,while the constraint condition was imposed on the first frequency of vibration of the system.The effect of introducing a sandwich panel within the roof assembly was evaluated,focusing on the mechanical and dynamic performances of the whole car body.A mass saving of 63%on the optimized components was achieved,corresponding to a 7.6%if compared to the complete car body shell.In addition,a positive increasing of 17.7%on the first frequency of vibration was observed.Encouraging results have been achieved in terms of weight reduction and mechanical behaviour of the innovated car body.
基金Project(2022YFC3004304)supported by the National Key Research and Development Program of ChinaProjects(52078487,U1934207,52178180)supported by the National Natural Science Foundation of China+2 种基金Project(2022TJ-Y10)supported by the Hunan Province Science and Technology Talent Lifting Project,ChinaProject(2023QYJC006)supported by the Frontier Cross Research Project of Central South University,ChinaProject(SKL-IoTSC(UM)-2024-2026/ORP/GA08/2023)supported by the Science and Technology Development Fund and the State Key Laboratory of Internet of Things for Smart City(University of Macao),China。
文摘In the realm of high-speed railway bridge engineering,managing the intricacies of the track-bridge system model(TBSM)during seismic events remains a formidable challenge.This study pioneers an innovative approach by presenting a simplified bridge model(SBM)optimized for both computational efficiency and precise representation,a seminal contribution to the engineering design landscape.Central to this innovation is a novel model-updating methodology that synergistically melds artificial neural networks with an augmented particle swarm optimization.The neural networks adeptly map update parameters to seismic responses,while enhancements to the particle swarm algorithm’s inertial and learning weights lead to superior SBM parameter updates.Verification via a 4-span high-speed railway bridge revealed that the optimized SBM and TBSM exhibit a highly consistent structural natural period and seismic response,with errors controlled within 7%.Additionally,the computational efficiency improved by over 100%.Leveraging the peak displacement and shear force residuals from the seismic TBSM and SBM as optimization objectives,SBM parameters are adeptly revised.Furthermore,the incorporation of elastoplastic springs at the beam ends of the simplified model effectively captures the additional mass,stiffness,and constraint effects exerted by the track system on the bridge structure.
文摘A new mechanics model, which reveals additional longitudinal force transmission between the continuously welded rails and the bridges, is established on the fact that the influence of the mutual relative displacement (among) the rail, the sleeper and the beam is taken into account. An example is presented and numerical results are compared. The results show that the additional longitudinal forces calculated with the new model are less than those of the previous, especially in the case of the flexible pier bridges. The new model is also suitable for the analysis of the additional longitudinal force transmission between rails and bridges of ballastless track with small resistance fasteners without taking the sleeper displacement into account, and compared with the ballast bridges, the ballastless bridges have a much stronger additional longitudinal force transmission between the continuously welded rails and the bridges.
基金the financial support of Iran Transportation Research Institute for doing this project(Grant No.91/1/5306)
文摘Deep mixed column （DMC） is known as one of the effective methods for stabilizing the natural earth beneath road or railway embankments to control stability and settlements under traffic loads. The load distribution mechanism of embankment overlying on loose subgrades stabilized with DMCs considerably depends on the columns＇ mechanical and geometrical specifications. The present study uses the laboratory investigation to understand the behavior of embankments lying on loose sandy subgrade in three different conditions： （1） subgrade without reinforcement, （2） subgrade reinforced with DMCs in a triangular pattern and horizontal plan, and （3） subgrade reinforced with DMCs in a square pattern and horizontal plan. For this purpose, by adopting the scale factor of 1：10, a reference embankment with 20 cm height, 250 cm length, and 93% maximum dry density achieved in standard Proctor compaction test was constructed over a 70 cm thick loose sandy bed with the relative density of 50% in a loading chamber, and its load-displacement behavior was evaluated until the failure occurred. In the next two tests, DMCs （with 10 cm diameter, 40 cm length, and 25 cm center-to-center spacing） were placed in groups in two different patterns （square and triangular） in the same sandy bed beneath the embankment and, consequently, the embankments were constructed over the reinforced subgrades and gradually loaded until the failure happened. In all the three tests, the load-displacement behaviors of the embankment and the selected DMCs were instrumented for monitoring purpose. The obtained results implied 64% increase in failure load and 40% decrease in embankment crest settlement when using the square pattern of DMCs compared with those of the reference embankment, while these values were 63% and 12%, respectively, for DMCs in triangular pattern. This confirmed generally better performance of DMCs with a triangular pattern.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.52008404,U1934217 and 11790283)Science and Technology Research and Development Program Project of China Railway Group Limited(Major Special Project,No.2020-Special-02)the National Natural Science Foundation of Hunan Province(Grant No.2021JJ30850).
文摘In this work,a method is put forward to obtain the dynamic solution efficiently and accurately for a large-scale train-track-substructure(TTS)system.It is called implicit-explicit integration and multi-time-step solution method(abbreviated as mI-nE-MTS method).The TTS system is divided into train-track subsystem and substruc-ture subsystem.Considering that the root cause of low effi-ciency of obtaining TTS solution lies in solving the alge-braic equation of the substructures,the high-efficient Zhai method,an explicit integration scheme,can be introduced to avoid matrix inversion process.The train-track system is solved by implicitly Park method.Moreover,it is known that the requirement of time step size differs for different sub-systems,integration methods and structural frequency response characteristics.A multi-time-step solution is pro-posed,in which time step size for the train-track subsystem and the substructure subsystem can be arbitrarily chosen once satisfying stability and precision demand,namely the time spent for m implicit integral steps is equal to n explicit integral steps,i.e.,mI=nE as mentioned above.The numeri-cal examples show the accuracy,efficiency,and engineering practicality of the proposed method.
基金supported by the Jiangxi Provincial Natural Science Foundation of China(Nos.20224BAB214063,20224BAB214064,and 20232BAB204083)the National Natural Science Foundation of China(Nos.52208347 and 52208348)+1 种基金the China Postdoctoral Science Foundation(No.2023M731436)the Key Projects of Jiangxi Provincial Department of Water Resources(No.202426ZDKT01).
文摘Interlayer soil in railway substructures is characterized by a fine/coarse soil mixture.Considering that the resilient modulus M_(r) of the mixture is influenced by the microstructure of fine soil,it is worthwhile to investigate this aspect further.In this study,the microstructure of fines was explored by mercury intrusion porosimetry(MIP),and its influence on the M_(r) of the mixture was studied by multi-stage dynamic triaxial tests with varying deviator stress amplitudesσ_(d).The results showed a fine matrix fabric obtained at water contents of fine soil w_(f)=17.6%and 13.7%(>the plastic limit of fine soil w_(p)=12%),and a fine aggregate fabric identified at w_(f)=10.6%(<w_(p)=12%).Interestingly,the influences of w_(f) andσ_(d) on the M_(r) of the mixture were observed:the rise inσ_(d) contributed to a decline in M_(r) when w_(f)>w_(p) but to an increase in M_(r) when w_(f)<w_(p).It was concluded that,for the fine matrix fabric(w_(f)>w_(p)),increasingσ_(d) induced a reduction in M_(r),while for the fine aggregate fabric(w_(f)<w_(p)),increasingσ_(d) gave rise to the growth of M_(r).The distinct M_(r)-σ_(d) behaviors for these two fabrics were explained by the competing influences between soil hardening upon loading and soil rebounding upon unloading.For the fine matrix fabric(w_(f)>w_(p)),considering its high deformability,the rebounding effect on M_(r) outweighed the hardening effect,and thus a decline in M_(r) occurred with the growth ofσ_(d).Conversely,for the fine aggregate fabric(w_(f)<w_(p)),the rebounding effect on M_(r) was secondary compared with the hardening effect based on the consideration of its low deformability,and thus an increase in M_(r) was observed with risingσ_(d).
基金The Doctoral Fund of Ministry of Educa-tionof China (No. 20050613007)
文摘By building the finite element model, the track parameters, including the ultimate longitudinal resistance, the length of the intermediate straight line, and the gap between spacer blocks, were analyzed for their influences on the longitudinal forces and displacements of the single turnout and turnout group, respectively. The results indicate that when the longitudinal resistance drops from 32 to 20 N/cm, the maximum additional longitudinal force of the turnout group increases by 19. 2%, and the maximum additional longitudinal displacement of the turnout group grows by 85.3% compared with 50.4% for the single turnout. When the length of intermediate straight line rises from 0 m to infinite, the maximum additional longitudinal force decreases by 38.8%, and the maximum additional longitudinal displacement by 80.3%.
文摘In recent years,with the development of road and railway transportation industries,a variety of complicated decisionmaking problems have emerged in real-world applications.It is urgent to analyze these problems from the perspective of theoretical and methodological innovations,and provide methods in management,decision-making and application so as to achieve efficient operations of traffic and transportation systems.These problems have
