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2024 Vol. 41, No. 10 Published: 2024-10-15

Urban Rail Construction Engineering Economy and Management Main Line: Engineering Geology and Subgrade Information Technology Research on Technical Standards and Specifications Main Line: Bridge Engineering Main Line: Tunnel Engineering Main Line: Electrification Engineering Urban Railway Development and Technology Research Main Line: Railway and Track

Main Line: Engineering Geology and Subgrade

	1	Application Research on Displacement Monitoring and Analysis of Stability of Large Soil Slopes
		LI Feng, JU Li, ZHONG Liang, LI Tianyu
		Research purposes: Large unstable soil slope has the characteristics of long deformation duration, high concealment of deep displacement and great damage of instability. According to the results of displacement monitoring and the engineering geological environment conditions of slope, the deformation characteristics of slope are studied, the displacement change mechanism is analyzed, and the deformation trend and stability of slope are comprehensively evaluated. Research conclusions:(1) According to the analysis of surface displacement monitoring data, the horizontal displacement of slope at different positions has obvious difference, the leading edge is the largest, and the trailing edge is the smallest. (2) According to the analysis of deep displacement monitoring data, the slope is in creep deformation stage. There are two potential sliding surfaces, shallow layer and bottom layer. The shallow sliding surface buried depth of 3~10 m is about 6 m on average, the deep sliding surface is located at the soil-rock interface, buried depth of 25~51 m, and the shallow layer displacement is greater than the deep layer. (3) Comprehensive analysis of surface displacement and deep displacement monitoring data shows that slope deformation has seasonal and multi-layer characteristics, and creep deformation is in a continuous development state and an aggravating trend. (4) The research results can provide reference for the stability evaluation of large-scale soil slopes.
		2024 Vol. 41 (10): 1-5 [Abstract] ( 10 ) HTML (1 KB) PDF (1825 KB) ( 2 )

	6	Application Research on Underwater Tunnel Geological Modeling Based on High Precision 3D Seismic Reflection
		LI Kai
		Research purposes: The construction of engineering geological models primarily relies on a large amount of drilling data and geological survey results. However, three-dimensional geological models constructed from point-based information often exhibit uneven data distribution and significant blind spots. Survey work for offshore bridge and tunnel projects predominantly relies on two-dimensional linear exploration, heavily dependent on drilling. This approach is characterized by high costs, long cycles, and high operational risks, making it challenging to meet the demands for detailed, rapid, and efficient geological modeling. This paper, based on the Jintang Subsea Tunnel Project of Ningbo-Zhoushan Railway, adopts the offshore three-dimensional seismic reflection method to explore the covered mountain development area in the Ningbo section. By combining stratigraphic interpretation and structural analysis results with drilling data, accurate three-dimensional structural and attribute geological models of the work area are constructed using well-constrained geological modeling techniques. Through three-dimensional visualization technology, the integration and analysis of engineering entities with geological models are achieved, expressing the spatial relationship between complex geological structures and engineering entities. Contact conditions between tunnel excavations and formations as well as structures are analyzed accurately and in three dimensions. This study effectively addresses the limitations of geological modeling in offshore transportation engineering. Research conclusions: (1) High-precision three-dimensional seismic reflection exploration can effectively identify spatial distribution information of the water bottom, Quaternary strata, underlying bedrock(covered mountain), and adverse geological structures (faults, fractured zones) in tunnel site areas, to provide a new approach for linear geological survey in offshore transportation engineering. (2) Three-dimensional seismic reflection exploration can effectively solve the problems of insufficient basic data, uneven spatial distribution, and blind spots in geological modeling for offshore transportation engineering. Well-constrained geological modeling techniques can enhance modeling accuracy and establish complete underwater spatial geological models, accurately simulating the morphology, position, and spatial contact relationships of formations and structures in the work area, thereby obtaining geological models of formations, structures, and attributes. (3) By integrating and analyzing engineering structural models with detailed three-dimensional geological models, the spatial relationship between complex geological structures and engineering entities can be accurately displayed through three-dimensional visualization technology. This allows for the intuitive analysis of rock and soil geological conditions in tunnel excavations, providing reliable basis and strong support for optimizing route longitudinal section design, BIM design, construction, operation and maintenance, and risk decision-making. (4) The conclusions of this study can provide references for offshore engineering surveys and geological modeling.
		2024 Vol. 41 (10): 6-12 [Abstract] ( 6 ) HTML (1 KB) PDF (3237 KB) ( 1 )

	13	Analysis of Deformation Control of High-speed Railway Subgrade on Expansive Soil Foundation
		YAO Yuchun, LI Anhong, CHEN Weizhi, DING Xuanming, CUI Xinzhuang
		Research purposes: Expansive soil foundation is widely distributed in China, and its strength decreases significantly after immersion. The swelling and shrinkage deformation caused by water absorption and loss is repeated, and the engineering hazard is extremely high. The existing railway and highway subgrade diseases are very prominent. The problems of expansive soil slope stability and subgrade slurry overflow have been solved. The deformation of ordinary railway and highway subgrade has also been well controlled, but its settlement control standard is 20~30 cm. High-speed railway uses millimeter level deformation as the control standard. The construction of high-speed railway subgrade on an expansive soil foundation must solve two technical problems: the expansion arch deformation of road cuts and low embankments, and the settlement deformation of high embankments. Research conclusions:(1) The expansion amount of natural expansive soil foundation after water immersion is significantly greater than the limit value of ballastless track railway maintenance. The flexible filling body of the roadbed has a good buffering effect on the expansion and contraction deformation of expansive soil. (2) During the construction period, the natural expansive soil foundation filling the roadbed can achieve more than 80% of the total settlement, and the composite foundation reinforcement treatment can exceed 90%. When the filling height on the overconsolidated expansive soil foundation is not high, the total settlement of the reinforced foundation and the natural foundation is relatively small. (3) Embankment-type cutting structure should be adopted for expansive soil foundation and low embankment engineering, with all roadbed areas replaced and drainage measures strengthened. Small diameter and small spacing CFG piles should be used for foundation reinforcement. Shallow layers of 4~6 meters should be reinforced for general embankments, and settlement calculation analysis should be conducted for high embankment foundation treatment based on general soil foundation. (4) This research result can provide a useful reference for the construction of high-speed railways on expansive soil foundations.
		2024 Vol. 41 (10): 13-17 [Abstract] ( 8 ) HTML (1 KB) PDF (674 KB) ( 1 )

Main Line: Railway and Track

	18	Research and Development of Railway Intelligent Line Selection System Based on Cost Graph Path Planning
		KONG Guoliang, HU Xuhong, ZHENG Zhilin, LI Dingfeng, LONG Xuyou, ZUO Feng, YUAN Wei
		Research purposes: The railway line selection has a wide range of areas, multiple influencing factors, and strong multidisciplinary comprehensiveness. The research and development of intelligent line selection is difficult, and the efficiency and effectiveness of its application have not yet reached widespread promotion. The intelligent railway line selection system is developed, key and difficult points are identified to break through them step by step, new perspectives are proposed on path planning, local optimization, human-machine interaction, etc., in order to supplement and improve existing theoretical methods, and improve the efficiency and quality of line selection design. Research conclusions: (1) Conducting system research and development through three steps: channel search, scheme optimization, and human-machine collaboration, and fully reusing automatic vertical section design as the basic function, can significantly reduce research and development difficulty and improve research and development efficiency. (2) A method for automatically exploring terrain in large scenes is proposed to obtain high cost areas for bridges and tunnels, and to construct a triangulation cost graph based on the boundary feature lines of the areas, which can improve search adaptability and accuracy. (3) Based on Dijkstra's shortest path search algorithm, automatic path planning can greatly improve search efficiency and effectiveness. (4) Adaptive optimization of horizontal and vertical lines, real-time linkage of horizontal and vertical lines, and system fusion based GIS line selection can flexibly meet practical needs and enhance system applicability. (5) The research results can provide reference for the development of intelligent line selection systems for railways and highways.
		2024 Vol. 41 (10): 18-23 [Abstract] ( 10 ) HTML (1 KB) PDF (2122 KB) ( 2 )

	24	Analysis of Short-wave Irregularity Characteristics of Urban Rail Transit Track Surface
		SHEN Longjiang, TIAN Chunxiang, HE Shizhong, CHEN Xiaofang, XU Jinhui
		Research purposes: In order to deeply analyze the characteristics of rail surface short-wave irregularity in urban rail transit, this paper analyzes the waveform characteristics and amplitude distribution law of rail surface short-wave irregularity, calculates and analyzes the spectral characteristics of rail surface short-wave irregularity, and puts forward the fitting expression of rail surface short-wave irregularity spectrum in urban rail transit. Research conclusions: (1) The irregularity of weld joint area occurs every 25 m, and its influence range is about ±1.5 m at the weld, and the waveform is mainly M-shaped (low joint). (2) The damping tracks in the small radius curve section all have obvious short-wave grinding waveforms, and have no long-wave grinding characteristics. (3) There are obvious sharp peaks in the short spectrum of the inner and outer rails in the curve section, which are mostly caused by rail corrugation, and the inner rail corrugation is more serious than the outer rail corrugation. (4) The proposed sixth-order polynomial fitting function can better reflect the short-wave irregularity characteristics of urban subway lines. (5) The results of this study can be used to guide the dynamic performance design of urban subway vehicles, and also provide theoretical basis for the state evaluation and maintenance management of urban subway lines.
		2024 Vol. 41 (10): 24-30 [Abstract] ( 8 ) HTML (1 KB) PDF (1374 KB) ( 1 )

Main Line: Bridge Engineering

	31	Research on Universal Calculation Algorithm of Effective Width of Concrete Beam with Box Section
		FU Anmin, WANG Yuquan, LIAO Lijian
		Research purposes: The calculation of the effective width of box sections is complicated and it’s difficult to form a universal algorithm due to the large number of box section forms and variable inflection points of the box section. In order to solve the problem that the conventional algorithm is only applicable to specific form sections and has defects in universality, this paper proposes a universal algorithm for calculating the effective width of the box section. Research conclusions: (1) The section was discretized based on the nodel lines in order to obtain the effective width of section suitable for different finite element software data formats. (2) By dividing the section into multiple areas to decouple the section, calculating the local nodel lines and merging them to form the global nodel lines, the calculation complexity of the nodel lines was reduced effectively, and the calculation of the effective width of complex sections with multiple inflection points was realized. (3) The computing module of each area is independent of each other, which effectively increases the universality of each calculation module and reduces the maintenance workload of the algorithm. (4) In each nodel line calculation module, a method of forming multilevel sub-branches according to specific classification order and calculating nodel lines step by step according to sub-branches was proposed, which ensures the accuracy and completeness of the local nodel line calculation results of complex sections with multiple inflection points. (5) Under the framework of this algorithm, the calculation of the effective width of the box section with any number of box rooms was realized by extension. (6) The algorithm has strong generality and wide applicability, and can be applied to the finite element modeling of concrete bridges effectively.
		2024 Vol. 41 (10): 31-38 [Abstract] ( 10 ) HTML (1 KB) PDF (628 KB) ( 1 )

	39	Research on Resistance Welding Process Parameters of Steel Skeleton in High-speed Railway Simply Supported Box Girders
		NIU Yuanzhi, ZHENG Hemin, ZHANG Shaopeng, ZHANG Shang, GUO Xinfei
		Research purposes: Currently, the fabrication of steel skeletons for simply supported box girders in high-speed railway construction primarily relies on manual tying, which is inefficient and costly. To address this issue, the authors of this paper proposed an automated resistance welding process for steel skeletons for simply supported box girders, which can replace traditional tying methods to enhance manufacturing efficiency and reduce labor costs. However, this welding process can cause some damage to the steel bars, potentially leading to fatigue issues at the weld points under repeated vehicle loads. The purpose of this study is to experimentally investigate the effects of different welding parameters on the static tensile strength and fatigue performance of cross-welded steel bars in the steel skeleton, to determine the optimal welding parameters to ensure the performance of the steel skeleton. Research conclusions: (1) The failure modes of the steel specimens produced by resistance welding differ between static tensile tests and fatigue tests. In the former, failure occurs as the transverse short steel bar detaches from the long steel bar at the weld point, while in the latter, it manifests as the longitudinal long steel bar breaking at the weld point. (2) The relationship between the welding parameters and the static tensile strength and fatigue life of the specimens is not a simple linear one, with the presence of local extremum points. (3) Considering both static tensile strength and fatigue life, the N3 welding parameter set demonstrates the best performance. The corresponding effective current value is 11.5 kA, the peak current is 16 kA, the voltage is 0.6 V, and the welding time is 9 cycles. (4) The findings of this study can be applied to the resistance spot welding of steel skeletons in high-speed railway construction, promoting the efficient production and development of simply supported box girders.
		2024 Vol. 41 (10): 39-43 [Abstract] ( 6 ) HTML (1 KB) PDF (1565 KB) ( 1 )

Main Line: Tunnel Engineering

	44	Hydrochemical Appraisal and Formation Mechanism of Xiangyang Karst Tunnels in Eastern Sichuan Province
		SONG Ci, YANG Ruifeng, XIE Zhan, YU Shuping, WANG Shengyang, ZHANG Yunhui, PEI Xiangjun, LIU Jianming, DAI Jinsong, ZENG Qinghua
		Research purposes: Water inrush is a major engineering hazard in karst water-rich tunnels, and its research is of great practical significance. Based on a total of 7 surface water samples and 35 groundwater samples, collected from Xiangyang Tunnel for hydrochemical analysis, this study takes Xiangyang Tunnel as an example to investigate the mechanism of water inrush in deep and long tunnels in karst mountainous areas in Southwest China and provides a scientific basis for the prevention and control of water inrush in karst tunnels along this route. Research conclusions: (1) The hydrochemical types of water samples in the tunnel area are mainly HCO₃-Ca, with weak alkaline and low mineralization. The chemical properties of surface water and groundwater are similar, and the hydraulic connection is close. (2) The hydrochemical composition is mainly affected by the weathering and dissolution of silicate and carbonate rocks, as well as cation exchange. (3) The Ca²⁺ and Mg²⁺ in groundwater and surface water mainly come from the dissolution of calcite and dolomite in limestone dolomite, and the weathering of feldspar minerals in clastic sandstone. (4) Na⁺ comes from atmospheric precipitation and the weathering of silicates. (5) Carbonate minerals plays a dominant role in rock weathering and dissolution. (6) The research results can provide reference for the design of tunnel lines in karst areas.
		2024 Vol. 41 (10): 44-51 [Abstract] ( 6 ) HTML (1 KB) PDF (1544 KB) ( 1 )

	52	The Study of Seismic Imaging Method in Detecting Hidden Karst at the Bottom of Tunnel
		WANG Shudong, MU Yuancun, GAO Shuquan, LI Xing, LIU Zufu, LIU Xin CHANG Juyou
		Research purposes: In the construction of karst tunnel of high-speed railway, it is necessary to find out the hidden karst at the bottom of the tunnel, which affects the safety of the tunnel, and what method can be used to quickly find out the depth, nature and range of the karst, therefore, the seismic imaging method is proposed and studied in this paper. Research conclusions: (1) Using the migration distance and fault width characteristics of the seismic imaging method, the plane physical connection with the adjacent survey line in oblique direction and short distance with the same characteristics, and the positive calculation and statistics of karst wave velocity, it is feasible to karst morpolohgy and drill holes to quickly discover the depth, nature and range of the hidden karst at the bottom of the tunnel which affects the safety of the tunnel. (2) It can detect the karst development and karst development, clay-filled karst caves, cavity karst caves and residual slag in different depths under the maximum depth of 30 m under the multiple survey lines at the bottom of the tunnel, and carry out engineering treatment, it is necessary to determine the best and effective scheme, which corresponds to cement grouting, high-pressure jet grouting pile, pile-board structure or masonry buttress, removal of residual slag, and the strength of the tunnel bottom after treatment is stable and does not sink or arch, and to ensure the smooth discharge of karst water, can ensure the safety of the tunnel. (3) We should pay attention to the inspection of the construction quality of the secondary filling layer of the inverted arch at the bottom of the tunnel. (4) The research results can be used to quickly find out the depth, nature and range of the hidden karst at the bottom of the tunnel, which affects the safety of the tunnel, to determine the best effective treatment program for reference.
		2024 Vol. 41 (10): 52-56 [Abstract] ( 9 ) HTML (1 KB) PDF (3832 KB) ( 1 )

	57	Research of Intelligent Detection Technology for Railway Tunnel Engineering Quality
		ZHANG Chen, SHI Feng, MENG Chao, LIU Guiwei, LI Bingxiu, TIAN Yang
		Research purposes: Railway tunnel defects in terms of disease have become an important hidden danger affecting the safety of China's railway operations, in which the quality of tunnel lining is particularly prominent. In response to the low level of intelligence in tunnel lining disease detection, inconsistent manual interpretation standards, and interference from equipment models and technical capabilities of interpretation personnel during the interpretation process of geological radar detection images, research is being conducted on intelligent detection technology suitable for railway tunnel lining quality. Using geological radar detection images of tunnel lining diseases as a sample library, image recognition algorithms are trained to achieve intelligent recognition of various diseases of railway tunnel lining, providing automated and intelligent tools for railway tunnel quality detection. Research conclusions: (1) The characteristics of geological radar defect images in tunnel lining were studied, and it was found that the determination of tunnel lining quality defects requires a high level of experience from the inspection personnel, and this work has a certain degree of subjectivity. (2) Build a geological radar image sample library for different types of diseases, train intelligent recognition models, and achieve fast and automatic recognition of different diseases. (3) Based on the quality inspection images of tunnel lining in a certain railway project, this technology is used for intelligent detection of lining quality. The recognition results show that this technology can effectively avoid human interference during the detection process, and improve the efficiency of detection and the accuracy of analysis conclusions.
		2024 Vol. 41 (10): 57-62 [Abstract] ( 7 ) HTML (1 KB) PDF (2633 KB) ( 1 )

Main Line: Electrification Engineering

	63	Application Research on Anti-loosening of OCS Structure and Equipment in Rail Transit
		WANG Yuhuan
		Research purposes: The development degree of rail transit has become a symbol of modernization and plays a key role in national economic development and social stability. Among them, the safety and reliability of traction power supply systems have gradually become the focus of public attention. The dynamic matching of catenary and pantograph in the power supply system is the key to ensure the smooth current collection of the locomotive. However, the high-frequency vibration caused by frequent alternating contact force can loosen components of the catenary, especially in high-speed railway operation, coupled with mechanical vibration and wind-induced vibration of trains. Therefore, the anti-loosening of equipment and components is an essential requirement for safety and reliability. The purpose of this paper is to analyze the comprehensive ability of catenary structure, equipment, connection mode between parts, failure mode of threaded connection, and matrix collapse. Through qualitative investigation, quantitative test, theoretical calculation, and finite element comparative simulation calculation, the technical performance of thread fastening and anti-loosening is compared and analyzed, and the anti-loosening ability is evaluated and the new technology for simple, long-term, and controllable thread connection is proposed. Research conclusions: (1) The proportion of carbon steel or carbon steel M16 and above bolts and nuts with added elements used in the overhead contact system is about 40%, but the control of tightening torque and the evaluation of anti-loosening performance are often ignored. (2) The anchor bolts of the inverted cone must be tightened accurately to allow the adhesive to detach from the body and produce expansion and compression, to better play their role. Therefore, precise control of tightening torque is an important safety indicator. (3) Through the analysis of the relationship between loosening torque and tightening torque, it is concluded that it is not necessary to completely prevent loosening as long as the loosening torque is greater than the tightening torque. Improper handling can lead to thread adhesion and jamming. Accurate control of tightening torque is the key to truly preventing loosening. (4) Precision torque control type anti-loosening nut achieves the most precise torque value with the simplest operation, ensuring reliable connection, controllable indicators, energy saving, and efficiency enhancement, and is more suitable for high-altitude operations on high altitudes. (5) The research results are mainly applied to bolt tightening and anti-loosening of contact network equipment, structures, and components.
		2024 Vol. 41 (10): 63-69 [Abstract] ( 8 ) HTML (1 KB) PDF (1571 KB) ( 1 )

Information Technology

	70	Research on Digital Base of Railway Passenger Station Based on Digital Analog Separation Technology
		QIU Shichao, WEI Yinghong, YU Yang, WANG Ran, WANG Dong, ZHAO Tengya
		Research purposes:With the continuous promotion and application of Building Information Model (BIM) in railway station building engineering, a large amount of basic digital assets will be formed after the completion of the project. Therefore, it is necessary to study new technical methods to improve the reuse rate of BIM basic data assets, solve the problems of large component resources, and the difficulty of data expansion in downstream users of the model, and achieve efficient utilization of BIM results, forming a railway passenger station digital base, and providing a basic data service platform for comprehensive business applications of digital twins. Research conclusions:(1) Based on BIM model, a railway passenger station data base is built using a visualization engine platform and relational database, to achieve digital delivery of 3D design results. (2) From the perspective of geometric and non geometric data processing, a lightweight development application of the system based on the digital analog separation technology route has been developed. (3) Through engineering application practice, the feasibility and completeness of this technical solution have been verified, which can support downstream users to expand and extend business functions using model data information.
		2024 Vol. 41 (10): 70-75 [Abstract] ( 8 ) HTML (1 KB) PDF (2869 KB) ( 1 )

Urban Rail Construction

	76	Experimental Research on Seismic Performance of High-strength Steel Bar Joints on the Top Floor of Subway Stations
		LI Hui
		Research purposes: Due to the need to lay pipelines, thick soil cover is required above the top plate of subway stations, resulting in a large load on the top plate and causing a large cross-section of the top beam. Because of the width limitation of urban road surfaces, it is necessary to reduce the column section to save underground space, resulting in a structural form of "strong beams and weak columns", which has an unfavorable effect on the seismic resistance of the structure. To improve the seismic performance of the top node of a subway station, this paper takes the beam-column node of a certain subway station as the research object, produces scaled model specimens, and conducts low-cycle reciprocating tests to study the influence of high-strength steel bars on the seismic performance indicators such as the failure mode, bearing capacity, and energy dissipation capacity of the top node. Research conclusions: (1) The nodes with high-strength steel bars and ordinary steel bars in the column are both failure modes of strong beams and weak columns, but the configuration of high-strength longitudinal bars can reduce the degree of column failure at the top beam nodes. (2) Configuring high-strength longitudinal bars in columns can significantly improve the bearing capacity and deformation capacity of top-level beam column nodes, delay stiffness degradation rate, enhance energy dissipation capacity, and thus improve the seismic performance of nodes. (3) The research results can provide a theoretical reference for the design optimization of beam-column joints in complex underground structures represented by subways.
		2024 Vol. 41 (10): 76-82 [Abstract] ( 10 ) HTML (1 KB) PDF (1866 KB) ( 1 )

	83	Key Technologies for Underground Excavation of Metro Station with Shallow Buried Depth in Sand and Gravel Stratum
		DAI Zhiren, HU Ruiqing, YANG Zigang, LI Xiaoqiang
		Research purposes: Aiming at the road traffic problems confronted by the open-cut method of subway station construction in the water-rich sandy pebble layer, this paper relies on the successful project of Chengdu subway station construction in water-rich sandy pebble layer for the first time using the concealed excavation method to carry out a study on the key technology of concealed excavation method, indicating the key technology of the concealed excavation guide hole setting and its excavation sequence, the way of over-advanced pre-strengthening of the strata, the type of initial support, the steel pipe columns with permanent-temporary combination, and the arched cover buckling arch and so on, and clarifying the feasibility of the shallow buried large span metro station with water-rich sandy pebble layer for the first time. The feasibility of using the concealed excavation method for the first time in the construction of the shallow buried large-span subway station in water-rich sand and pebble layer was clarified. Research conclusions: (1) Based on the concept of modular tunneling approach, with the pre-support of tube curtain with large rigidity, the basic principle of the pilot tunnel is clarified, and then multiple pilot tunnels are adopted in the construction of steel pile pillars, tunnel roofs. The underground excavation of metro stations with large spans and shallow buried depth can be realized. (2) The precise control of construction accuracy and stratum disturbance of tube curtains with large rigidity plays a key role in the control of stratum settlement. The corresponding basic construction principle is accurate positioning, timely correction, not enough slagging, strict control of over-digging, low-speed drilling at the beginning, and then even speed drilling. (3) Based on the passive bearing properties of initial support, grid steel has a relatively better economic effect and construction convenience, the overall flexural stiffness after shotcrete increases to nearly 8 times. The corresponding stiffness of grid steel is larger than H plate steel after shotcrete. So, grid steel should be adopted as far as possible. (4) In the center pilot tunnel, the snakelike middle column embedded with inverted L-shaped steel plate at the top can realize the effective connection of the lining structure on both sides and the effective horizontal force transmission. The hydraulic reverse circulation drilling machine can meet the need for high-precision permanent steel pipe pillar construction within a small headroom. (5) This paper can provide a reference for the similar project in the sand and gravel stratum in the future.
		2024 Vol. 41 (10): 83-89 [Abstract] ( 9 ) HTML (1 KB) PDF (1581 KB) ( 3 )

Urban Railway Development and Technology Research

	90	Optimization of Urban/Suburban Train Operation Schemes on Existing Railways
		ZHOU Bo, SONG Weiwei, CHEN Congcong
		Research purposes: Against the backdrop of utilizing existing railway resources for the development of suburban (commuter) railways, this study aims to improve the operational efficiency of suburban railways to meet passenger travel demands. By analyzing passenger behavior under different arrival patterns, a traffic allocation method for suburban railways under a mixed arrival pattern is proposed. Based on the "national ownership of lines, co-management by national and local railways" model, a multi-objective optimization model is constructed, which comprehensively considers passenger travel time, operational costs, and local government costs. The model is solved using a genetic particle swarm optimization algorithm to optimize train scheduling plans. Research conclusions: (1) Empirical analysis of peak morning passenger flow data from a suburban railway line shows that the constructed optimization model for suburban railway scheduling can significantly improve operational efficiency. (2) The model shortens total passenger travel time by 34.8% during peak morning hours, reduces railway operational costs by 10.2%, decreases local government costs by 11.5%, and saves 10% on vehicle acquisition costs. (3) The results of this study can be applied to project planning decisions and operational optimization for suburban railways utilizing existing railway resources.
		2024 Vol. 41 (10): 90-96 [Abstract] ( 9 ) HTML (1 KB) PDF (561 KB) ( 1 )

	97	Research on the Selection Method of Reasonable Line Spacing in Open Line Section of Regional Railway
		LIU Daotong, FAN Xiaozhen, WANG Shuwei, ZHU Xiaohai
		Research purposes: The regional railway is mainly laid in the form of ground and elevated, and the line spacing will directly affect the line design, bridge deck layout, engineering investment, etc. There is a significant difference in the selection of line spacing in domestic regional railways, and the existing research lacks strong guidance on the working conditions of building (structure) installation between lines. This article conducts research on reasonable line spacing by setting selection principles, analyzing influencing factors, determining typical operating conditions, conducting economic and technological comparisons, and providing a set of highly applicable selection methods. Research conclusions: (1) This paper proposes a method for determining the reasonable line spacing of regional railways: Firstly, determining the minimum line spacing of straight sections based on the vehicle model. Secondly, determining the reasonable spacing between straight lines based on the buildings, equipment, and beam types. Thirdly, adjusting the reasonable line spacing based on curve widening and construction methods. (2) Suggest adjusting the minimum line spacing of B-type vehicles to 3.4~3.6 m based on the limit requirements. (3) From the perspective of controlling investment, it is not advisable to set up buildings or structures between lines; From an overall functional perspective, evacuation routes should be set up between lines, and overhead contact system pillars should be set on both sides. (4) The values and curve radius range for widening the line spacing in curved sections have been determined for various vehicle models. (5) The research results can provide useful references for the selection of regional railway line spacing.
		2024 Vol. 41 (10): 97-103 [Abstract] ( 6 ) HTML (1 KB) PDF (621 KB) ( 2 )

Research on Technical Standards and Specifications

	104	Discussion on the Standard of Main Line Spacing for 600 km/h High-speed Maglev
		CHANG Yonghua, XU Xubao, MU Hanling
		Research purposes: Line spacing is an important parameter for route selection, which is affected by the basic building limit of maglev train, train rendezvous pressure wave, vehicle dynamic performance and other factors. Based on the research requirements of 600 km/h high-speed maglev superconducting electric levitation, and referring to the research results of high-speed maglev and high-speed railway system, this paper studies the line spacing of superconducting electric levitation from the aspects of aerodynamic performance, safe space, magnetic field fluctuation and engineering cost, and gives the suggested values of line spacing parameters. Research conclusions: (1) Numerical simulation analysis based on aerodynamics: the influence on the pressure wave/aerodynamic force of the car body surface rendezvous in the open line section is greater than that in the tunnel. (2) The train transverse displacement corresponding to the line spacing of 5.4 m to 6.0 m is less than the U beam sidewall guide clearance 64 mm, which meets the requirements of the sidewall guide clearance. (3) The line spacing of 5.8 m is more beneficial to save engineering investment and reduce vehicle cost, and to meet the requirements of magnetic field fluctuation distribution of superconducting magnets. (4) The research results can be applied to the line design of high-speed maglev project
		2024 Vol. 41 (10): 104-109 [Abstract] ( 7 ) HTML (1 KB) PDF (1610 KB) ( 2 )

Engineering Economy and Management

	110	Research on Negotiation-based Decision-making of Tunnel Construction Schemes under Agent Construction Management
		XUE Jinping
		Research purposes: The selection of tunnel construction schemes under the management mode of local railway construction by proxy is a complex game problem that is influenced not only by numerous objective factors but also by the subjective preferences of different stakeholders. Through this study, it is proposed to establish a negotiation-based decision-making model for tunnel construction schemes to address the selection of tunnel construction schemes under complex construction management modes. Research conclusions: (1) The selection of tunnel construction schemes requires comprehensive consideration of objective factors such as engineering investment, construction duration, implementation difficulty and risks, as well as project advancement and coordination difficulties. (2) The selection of tunnel construction schemes under the construction by proxy management mode requires comprehensive consideration and balancing of the interest demands of various stakeholders, including the owner unit, the construction proxy unit, and consulting units. (3) By introducing the theory of group risk decision-making, simulating the negotiation and game process among stakeholders on conflicting opinions, a decision-making model based on spiral advancement through negotiation theory is established. (4) Through case demonstrations, the spiral advancement decision-making model can compensate for the imperfections in current tunnel construction scheme decision-making, effectively simulating the actual decision-making process under the local construction by proxy mode. (5) The research in this paper can provide a certain theoretical reference for the research on scheme decision-making under complex construction management modes such as PPP and EPC.
		2024 Vol. 41 (10): 110-116 [Abstract] ( 7 ) HTML (1 KB) PDF (1103 KB) ( 1 )

	117	Seismic Resilience Assessment Method of Subway Station Based on Fragility Analysis
		LEI Chong, SUN Bo, ZHANG Dongming
		Research purposes: The structure of the subway station is buried deep underground, once it is damaged by an earthquake, disaster prevention, rescue, and post-disaster repair will be very difficult, and will cause huge economic losses and casualties. Improving the earthquake resilience of subway stations is an important guarantee for sustainable development. This paper aims to propose a simple and practical method for evaluating the seismic toughness of subway stations, which can be used to evaluate the seismic toughness of typical subway stations under different site conditions and provide a decision basis for improving the toughness of subway stations. Research conclusions: (1) The seismic toughness evaluation method not only considers the structural part but also considers the non-structural components, which is more reasonable and real. (2) The seismic vulnerability curves of subway station structures provided in this paper are more comprehensive and practical, considering the situations of underground two-storey single-span, two storey double-span, and two-storey triple-span in class Ⅰ, Ⅱ, and Ⅲsites, respectively. (3) With the increasing number of subway station spans, the overtaking probability decreases under different damage states, and the station tends to be safe; As the stratum decreases from the Class Ⅰ site to the Class Ⅲsite, the overrunning probability becomes larger under different damage states, and the station tends to be dangerous. (4) The results of this paper can be used to evaluate the seismic toughness of subway stations.
		2024 Vol. 41 (10): 117-126 [Abstract] ( 11 ) HTML (1 KB) PDF (1722 KB) ( 3 )