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In order to solve the problems of low measurement efficiency and high safety risks of personnel working on the line faced by the traditional single-point measurement means in the cross-section measurement of existing lines, vehicle-mounted mobile measurement technology was adopted to carry out the application research of cross-section measurement of existing railroads, and the process and method of technology application were introduced from three aspects: acquisition equipment, data acquisition and data solving. Based on the LiDAR point cloud of the whole section along the railroad line rapidly collected by the technology, the rail model reconstruction and route center extraction method with POS trajectory line guidance and two-step ICP alignment was proposed, and on this basis, the data processing method of section point cloud segmentation and attribute point automatic calculation was designed, which realized the rapid batch production of the results of the cross-sectional measurement of the existing railway lines. Combined with the application of a railroad project to build a second line, the results show that: the elevation accuracy is 19. 2 mm, distance accuracy is 16. 1 mm, which meet the specification requirements of the reconstruction of railroad engineering measurement. The method can effectively improve the efficiency of the existing line cross-section measurement, significantly reduce the amount of on-line work, and change the status that railroad crosssection measurement mainly depends on the manpower, which provides technical support and safety guarantee for the existing railroad cross-section fast measurement. [ABSTRACT FROM AUTHOR]

With the adjustment of urban spatial planning and industrial layout, the requirements for the service functions of suburban railway are correspondingly increased, however, the traditional functions of the existing railway are difficult to meet the requirements of the situation. Therefore, we should deeply mine its diversified functions and find a reasonable way to achieve them and improve the comprehensive benefits of the project. Based on the spatial distribution, hub introduction, network connection of the existing railway, it is proposed that the functions include traffic reinforcement function, guidance function and city publicity function. The realization of transportation functions can be divided into two modes: direct purchase of services and technical transformation and reuse, which need to be promoted by both local government and railway administration. The realization of development function requires the establishment of a two-way interactive mechanism between the reconstruction of existing railways and land planning. Urban publicity function is realized through integration and interaction of static urban resources and dynamic urban trains. The functions of existing railways are realized through qualitative and quantitative analysis based on classic cases. [ABSTRACT FROM AUTHOR]

In order to solve the problems of existing railway station section survey limited by GNSS-RTK satellite signal, low efficiency and difficult measurement conditions, this paper proposed a new technology of using knapsack mobile 3D laser scanning system to survey existing railway station section. The system could quickly and efficiently collect dense 3D point cloud data in the survey area without GNSS-RTK signal. The paper adopted the research method of combining theory with practice. First, through the research of SLAM algorithm and point cloud registration algorithm, the feasibility of the knapsack mobile 3D laser scanning system in the section survey of existing railway stations and yards was theoretically verified. Then, taking the Guangzhou East Railway Station reconstruction project as an example, a detailed survey process was developed, including route planning, control point layout and measurement, field data acquisition, office data preprocessing. Through the implementation of a series of measurement steps such as point cloud registration and splicing, multi-source data accuracy evaluation, etc., it was verified that the mean square error of the section measurement elevation of the knapsack mobile 3D laser scanning system in the existing railway station yard reached 0. 025 m, which met the measurement requirements of the existing railway station yard section. [ABSTRACT FROM AUTHOR]

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Copyright of Railway Investigation & Surveying is the property of Railway Investigation & Surveying Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Due to the many constraint conditions, construction difficulties, and high control standards, and the impact of new line construction on existing lines, the construction of culvert extensions in widened sections of loess areas has become a form of control in railway construction projects. This work analyzes the technical difficulties of culvert extension construction schemes based on a practical engineering case. A scheme to provide culvert protection against slight disturbances is determined, and the construction schemes of the culvert extension structure and transition section filling are optimized. The rationality of culvert extension control measures and the influence of construction on the existing line are then studied based on the monitoring data for each stage. The results show that the implementation of the slight disturbance culvert protection has little influence on the existing line, and has the greatest influence during steel sheet pile construction (<0.5 mm). We symmetrically construct the culvert extension structures (transverse) and transition section filling (longitudinal and transverse) to effectively reduce the influence of differences in the deformation value between the two sides of the existing line at the same level as the existing line. The deformation of the upper side of the culvert fluctuates with the construction of the composite foundation and shows an overall upward trend, while the deformation increases first and then decreases in the transition section, and the deformation of the upper side of the culvert is larger than that of the transition section. The level gauge deformation of each side decreases abruptly at the filling stage of the bottom plate, side plate, top plate, and splayed wall. The settlement value of the level gauge of each station increases nonlinearly with the increase in the filling height of the transition section, and the settlement variation value of the transition section at each filling stage is higher than that of the upper side of the culvert. [ABSTRACT FROM AUTHOR]

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Underground construction will have more or less adverse effects on adjacent existing buildings with more and more existing buildings above ground. However, this situation has only been reported by a small number of researchers. In view of this, this article takes the existing airport line shaft and horizontal passage project in the western suburb of Beijing Metro Line 12 as the background to study the impact of the construction of subway station and shaft passage on the adjacent existing railway. Based on the above project reality, under the action of pavement load, the effects of different parameters (the distance between the surface measuring point and the middle line of the transverse passage and the substep of construction loading sup step) on the surface settlement and track deformation of the shaft and cross-passage through the existing railway are studied by numerical analysis method. The calculation results show that the construction method of shaft and cross passage is reasonable. The comprehensive reinforcement measures of subgrade, rail and hole are effective, effectively controlling the deformation of subgrade and rail within the standard value (surface settlement ≤60 mm, rail deformation ≤6 mm). In addition, the numerical simulation data can better represent the actual situation as a whole.

Copyright of Railway Investigation & Surveying is the property of Railway Investigation & Surveying Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

To research the renovation mode of existing railway, make full use of resources, revitalize railway assets and enhance the value of the land and the quality of the cities along the lines, this paper studies the function of existing railways from the perspectives of superior policy, urban development, travel characteristics, integrated transportation system, operation and management, and analyzes the necessity and feasibility of public transport renovation. By analyzing such factors as station position, land use along the lines, connection of different modes of transportation and passenger flow level, this paper deeply discusses the function and demand characteristics of the lines, and provides references for further study of XiHu railway renovation. [ABSTRACT FROM AUTHOR]

Due to the many constraint conditions, construction difficulties, and high control standards, and the impact of new line construction on existing lines, the construction of culvert extensions in widened sections of loess areas has become a form of control in railway construction projects. This work analyzes the technical difficulties of culvert extension construction schemes based on a practical engineering case. A scheme to provide culvert protection against slight disturbances is determined, and the construction schemes of the culvert extension structure and transition section filling are optimized. The rationality of culvert extension control measures and the influence of construction on the existing line are then studied based on the monitoring data for each stage. The results show that the implementation of the slight disturbance culvert protection has little influence on the existing line, and has the greatest influence during steel sheet pile construction (

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

With the large-scale construction of city subways, the down traversing formed by subway running tunnels through the existing railways or railway yards are increasing day by day. Down traversing in shield method becomes common; however, the engineering cases which can be referable in the down traversing formed by the shallow-buried excavation of double-arch tunnels through the existing railways are very little. The ability to effectively control the excavation of shallow-buried subway tunnels can directly affect the safety of railway operation. According to the engineering characteristics of the down traversing formed by the shallow-buried excavation of double-arch tunnels in loessial layer, this paper proposed the standards for railway bed and track settlement control, and offers underground water treatment measures with assistant steps implemented on the ground surface during construction, so as to ensure the railway operation safety during the construction of the tunnel. Moreover, this paper applied MIDAS-GTS finite element software to make numerical simulation analysis of the down traversing formed by the double-arch tunnel through the railway and obtained the deformation laws during down traversing. The calculations suggest the railway track deformation caused by the down traversing construction of the double-arch tunnel in this project can meet related control standard requirements. There’s certain reference value contained in the deformation laws for the point locations of monitoring measurement. The research conclusions can provide scientific proof and technical guidance for the design and construction of this running tunnel project in order to offer reference for similar projects in the future.