Journal of Railway Engineering Society

Research methods: Some focus issues have been put forward in the design of difficult mountain railways based on the experiences in survey，design and coordinating construction of many railways in southwestern China.

Research Conclusions: In order to improve the design level of railways in difficult mountain area a proper route aternatives should be chosen and the main technical standards should be determined by comparison. The long and deep section of sufficient grade and extension of line should have top-down alignment， avoiding shallow burying tunnel and tunnel group as much as possible. We should identify the geological conditions for large-scale spoil site and avoid man -made geologic hazard.

Research methods: Taking the underground river found in the Wulong tunnel for example，this paper carries out the statistics，analysis and summary by applying the karst developing theory with integrally-surveying method.

Research results: The developing flow area of underground river is divided into smooth area and clogging area which solves dispute on karst developing rules and how to deal with of WuLong tunnel for long time and can be used widely for survey and engineering treatment of underground river in the tunnel under the similar conditions.

Research conclusions: Based on the situations of transverse slope，length and filling materials of the underground river revealed by excavation in course of construction，where is the underground river located，in smooth area or in clogging area could be judged，through which the engineering treatment and possible direction of relocation of line could be guided macroscopically ， and correspondingly the geological forecast could be conducted according to the location of the underground river ， for the purpose of avoiding the appearance of disaster.

Research methods: Refering to some regulation and experience at home and abroad，this paper studies and compares the subgrade filling ， groundwork treatment ， transition segment location，economy of subgrade and bridge，etc. for Shi Jiazhuang-Zhengzhou passenger dedicated railway line.

Research results: For the high speed passenger dedicated railway line，the subgrade filling had better be crude and eligible or after improving test ， the proper treatment measure should be adopted to control settlement ， the transition segment should be properly designed and the height and section for the bridge and subgrade should be confirmed in reason.

Research conclusions: In the design of ballastless track railway subgrade of high-speed passenger dedicated line， especially in plain area. We should emphasize considering on subgrade filling ， settlement control ， transition section and subgrade and bridge compare etc. and confirm the best scheme by some necessary tests and methods of economy and technique comprehensive comparison.

Research methods: The calculation and analysis were made for the entire structure by adopting three-dimensional space model for subgrade，foundation and upper structure with the aid of large finite element MIDAS program and elastic foundation beam method to simulate the effect on the foundation with spring.

Research results: The calculation results show that the computed settlement regulation and distribution regulation of internal force of raft foundation are matched with the actual deformation and stress of raft foundation.

Research Conclusions: The analysis results show it is feasible to design a raft foundation by taking the interaction of subgrade，raft foundation and structure into account.

Research methods: This paper uses the methods of in-situ test and theoretical analysis to do research.

Research results: The distribution of the earth pressure on a cable anchor tied-back pile-slab wall flexible retaining structure on embankment's shoulder or slope was gained from the research.

Research conclusions: For the prestressed cable anchor tied pile-slab wall on embankment's shoulder or slope，the distribution and size of the earth pressure become more complicated for the action of the anchor prestress. The earth pressure acted on the pile and slab can be cut into two parts: one for the total earth pressure of strip limit equilibrium and the other for the total earth pressure of active Coulomb when the influence of the anchor prestress is not considered. Secondly the enlarged earth pressure caused by the anchor prestress. In design of this type of retaining structure，the earth pressure acted on the pile and slab are the same in quantity ，and can not be considered the decreasing effect for the pressure caused by the”soil-arching effect" ; The calculation of the moments in the pile of this type of structure must consider the influence of the distribution and size caused by the anchor prestress; The earth pressure caused by the wall top ground rectangular traffic loads can be gained from the elastic theory.

Research methods: Its interior stress characteristics and distributional rule of extra stress are studied by three dimension numerical simulation in this paper ,and consummate the structure design. More ever its reasonability and validity in engineering are validated by field tests.

Research results: Numerical simulation condition is simple，and the stress characteristics and distributional rule of extra stress in planks are definitude. The structure design will be consummated with it. More ever by field test , the reasonability of structure and compressive strength of planks are availability with extra stress，and it can supply action of anchor works in time.

Research conclusions: Cross superposition planks is a new type of pressed structures in anchor engineering. It has some advantages，namely prefabricated，conveyed and assembled conveniently，shorter time limit for a project , cheaper cost ,etc. and it has the application value.

Research methods: Take Xinkai River Extra Major Bridge of Beijing-Tianjin Intercity Rail Transit for example，the stress conditions of cross-section with different web slops of box beam are calculated，compared and analyzed.

Research results: Because the roof in the cross selection of inclined web box beam bears the tension and bending moment the web slope of box beam is larger the tension in roof is stronger. Through the calculation of distributed steel the cross-section structure with web slope of 3:1 was adopted to the simply supported box beam of Xinkai River Extra Major Bridge of Beijing-Tianjin Intercity Rail Transit.

Research Conclusions: For the choice of web slope of prestressed concrete box beam，it is not only necessary for consideration of making the slope coordinate with the entire bridge，but also necessary for full consideration of coordination with the whole local environment ， and the more important point is to find out the rational cross section which not only satisfies the stress requirement ， but also is practical and elegant.

Research results: In the construction of composite girders of Gulang River Bridge on the second line of Lanzhou-Wuwei Railway , the corresponding construction proposal is adopted to ensure the safe，reliable and successful construction of this project.

Research Conclusions: The selection of construction methods，determination of construction procedures，on-site construction organization and safety control for bridges across existing lines must be standardized so as to get good effects.

Research methods: The integrated method of economic and technical analysis is adopted based on the features and experience of design of railroad-overpass bridge.

Research results: In view of taking construction method and making structural design of railroad-overpass bridge appropriately to guarantee the safe operation of the railway, the appropriate common schemes of overpass bridge available for railway section and terminal are presented.

Research conclusions: For the bridge in railway section，it is adapted to use box beam，T beam and hollow slab beam and constructed by adopting precast erection method. For the bridge in railroad terminal，it is adapted to use cable- stayed bridge，large-span rigid frame bridge or composite steel and concrete beam bridge and constructed by adopting erection methods of swing，cantilever and jack-in.

Research methods: That were scientific research experimentation，investigation，expert-consultation，drawing on the domestic or overseas correlative research fruit and excellent criterion，and the success experiences that come from the completed projects.

Research results: This paper gained these new content that exists mainly in the tunnel design conception，the portal project the tunnel support-structure system，the waterproofing & drainage of tunnel } and the system that can rescue people and prevent form disaster and should be emphasized and consummated in tunnel design in future by compiling the code for design on tunnel of railway(TB 10003-2005).

Research Conclusions: As long as people emphasize the aspects that were presented in this paper and follow the conceptions that based on the ideas，namely ”human first provide service for transportation，system optimization , with a view to development and build friendly circumstance"，people should can design lots of safe，reliable，economic and perdurable hundred-years tunnel project for the future.

Research methods: The geophysical prospecting on ground surface and in tunnel horizontal drilling and incline drilling in tunnel , test of fillings in cave，theoretical analysis are applied.

Research results: Through integrated prospecting and theoretical analysis，the basic features and disaster features of 3 caves developing and filling are found out. The formation mechanism of the caves has been defined preliminarily. The potential geological disasters of the 3 infilled caves have been disposed.

Research conclusions: Bedding detachment and longitudinal tension fractures located at core and eastern wing of the Maoba syncline cutting by transverse tension fractures（NW~NWW)，form the initial space and route way , which are the passage the deep cycle of karst aquifer. A type of deep flow cycle named inverse siphon cycle forms. The flow water dissolves the carbonate rocks along the route way. Conduits are formed by perennial corrosion of the water. The great cave forms due to corrosion and collapse of ceiling the cave. The cave is filled by clayey soil，which deposits due to the changes of the flow.

Research methods: The numerical simulation analysis，pantograph and catenary numeration model are used to uneven-ness of Overhead Rigid Suspension.

Research results: The current collection performance depends on its pantograph compliance characteristics and unevenness of its contact surface.

Research Conclusions: The unevenness of Overhead Rigid Suspension is the basis of study on vibration of pantograph with rigid suspension，reducing the unevenness，and the current collection quality will be promoted.

Research methods: The power factor of traction substation is determined through calculation of integral power factor of us traction loads.

Research results: This method can be used to more accurately reflect the power factor of traction substation.

Research Conclusions: By the calculation of integral power factor the power factor of traction substation can be worked out relatively accurately under the condition of the different types of locomotives and the different pairs of trains on railway line shared by passenger and freight trains.

Research methods: In this paper an accurate water tree model has been created .We have successfully developed a new hot-line diagnostic method called”high frequency superposition method”.We superpose a voltage with high frequency but low amplitude on the shielding layer of power cables to make the loss current more obvious. Then we use fractal methods to analyze loss current signals collected.

Research results: Degradation of XLPE cable by water trees gives rise to harmonics in the loss current. Harmonic components arise as a result of nonlinear voltage-current characteristic of water trees. The fractal dimension of loss current waveform increases because of the growth of harmonics. We calculate 3 fractal dimensions including capacity， information and correlation. We discuss the interrelationship between fractal dimension and harmonics.

Research Conclusions: The fractal dimension provides an extremely good indication of the state of degradation which can be used as a judgment for hot-line dielectric degradation.

Research methods: According to the comparison and analysis of design proposals and the capacity calculation analysis in the recommended proposal of the entrance/exit line from depot of Guangzhou Metro Line 3，this paper studies the reasonableness and applicability of the design proposal.

Research Conclusions: Under the restriction condition of land use and position of station and depot of Guangzhou Metro Line 3，the optimized design proposal has a strong advantage，which can meet the requirements of new operation mode of Metro Line 3.

Research methods: This paper analyzed the origin，the radiating way，and the controlling method of track vibration， then investigated some track damping structure used at present.

Research results: This paper summarized the design principles and design methods of track damping; And analyzed the kinds of track damping structure pattern structure character function effect and project cost. This paper also sorted the structure according to function effect and suggested the new pattern，new material and new technics for track damping structure.

Research Conclusions: Track damping is one kind of systems engineering. In order to meet the national environment protection requirements，we can adopt the measures of track damping and do the general treatments.

Research methods: In accordance with the requirements of operational management and in combination with the technology development of making up network of telecommunication transmission system，the comparison and research were made for some programs from the areas of the principle and technology of making up network and composition of telecommunication transmission system for urban mass transit.

Research results: The choices in technology and system composition of telecommunication transmission system for urban mass transit were presented under the different operational management mode.

Research Conclusions: The following suggestions were put forward: constructing network in different levels，choices of transmission system in technology ， level composition of transmission system，plan and construction of control center of telecommunication transmission system，management of transmission network and synchronously construction of clock，etc.

Research methods: Based on the metro fire cases，the analysis was made for the characteristics of metro fire，the special research was done for the disaster design for metro station from the fields of platform type and evacuating passengers safety，and the countermeasures for disaster prevention were demonstrated for metro station.

Research results: The countermeasures for strengthening disaster prevention design were proposed for the different station types and transfer functions，and the practical suggestions to the disaster prevention were put forward for large- sized comprehensive transportation terminals.

Research conclusions: Metro fire can cause serious harm，so the attention should be paid to the disaster prevention design. It is proposed that for the station type，the priority should be given to island platform station with satisfying the requirements of separation and evacuation for fire prevention，and the fire prevention plan should be will worked out for the architectural space of large-sized transfer terminals in combination with the down-going square and entrance passage.

Research methods: This paper combined academic analysis，the operation practice and the research of the overseas instance in the subway. Also a special technical meeting with the fire fighting department was held to discuss the issue with many experts.

Research conclusions: In the cold area，the temperature of the tunnel could be under zero degree ; Dry hydraulic system needs no heat preservation measures; Dry hydraulic system can meet the time requirements of hydrant operation ; Drain tap ， deluge valve and other apparatus are needed for the dry system.

Research methods: This paper recommends optimal plan through technical-economical comparison and operating effect analysis among the capacity expansion plans of breaking-up and sorting system.

Research results: The reasonable choice of capacity expansion plan of breaking-up and sorting system should be confirmed based on the layout of railway hub，under the principle of concentrated task，considering wagon flow of railway hub， expedite joining local wagon flow distributing center together reducing operating cost expedite management saving project investment and adaptability capacity.

Research conclusions: This paper recommends reconstructing Chongqing west marshalling station as the capacity expansion plan of breaking-up and sorting system in Chongqing railway hub.

Research methods: The discussion is carried out in combination with elevated station on Jiaoxin Line of Chongqing Light Rail Transit which is a straddle-type monorail traffic mode adopted first in China.

Research results: This paper puts forward the analysis and calculation methods，structural requirements，displacement and deflection value and passenger comfort requirements for elevated station.

Research conclusions: The elevated station need satisfy not only”Code for structural design of building"，but also” Code for design of railway bridge and culvert”. The light steel structure should be adopted for platform shed. The analysis on integral dynamic behavior of structure of station built on T-type single column pier should be carried out.

Research methods: The research is based on station adjustment and design status of Jiao Ji railway line.

Research results: This paper identifies the station distributing and task properties according to the factors of distance between stations，volume of goods traffic and passenger flow attracting ， presents turnout ， design standard of 200km/h mixed passenger and relight railway station design through the summary of station design.

Research Conclusions: At present temporary rule is recognized as the design guide for 200 km/h and above 200km/h railway trunk line. We can take the actual operating results of the Jiao Ji railway as the reference to improve the technique system.

Research methods: By analysing the status in front of Shenyang Railway Station we force the establishment of subway station at this station into categories，make analysis and study for each item to solve this problem in different ways.

Research results: Deep Shenyang Railway Station rooms and its main historic buildings. As to part of existing buildings， we take the means of removal and reconstruction to solve the construction of subway. We also leave development room between subway station and railway station to meet the demand of railway and long term municipal construction.

Research Conclusions: For the matter of building subway in historical block of ancient city it combines actual situation of surrounding buildings and takes the means of keeping，reasonable utilization and proper reconstruction in its design to deal with the relationship between subway and environment. At the same time，for municipal auxiliary project that hardly finished synchronistically with subway construction，it is necessary to leave enough development room in order to fulfill sustainable development of subway and urban construction in the future.

Research methods: According to the real construction situation of railway station under civil air defense under the East Straight Street in Haerbin，the analysis and research have been made by adopting the methods of finite analysis and structure analysis on the railway station under civil air defense based on the analysis of initiative underpinning method.

Research results: After two underpinning to marketplace structure，the possible different settlement of 1 .7-2. 4 mm are banished and then the maximal settlement between side walls and pillars of 8. 4 mm is eliminated. In the whole construction，the method assures the traffic in sequence and the business in normal. And it is an effect method to put in practice.

Research conclusions: It is feasible to adopt the underpinning method to marketplace underground in construction. There are many questions to research in design of buildings which are in the condition of having buildings underground and adopt the initiative underpinning technology，and it is the research direction in the following work.