Journal of Railway Engineering Society

关闭×

The mobile platform

Office Online

Journal Online

Archive

Member Service

2024 Vol. 41, No. 9 Published: 2024-09-15

Urban Rail Construction Engineering Economy and Management Main Line: Engineering Geology and Subgrade Information Technology Main Line: Bridge Engineering Main Line: Tunnel Engineering Main Line: Electrification Engineering Risk Management and Research Engineering Machinery

Main Line: Engineering Geology and Subgrade

	1	Study on the Stress of New Pile-sheet Wall-Existing Cantilever Retaining Wall Structure
		ZHAO Wenhui, ZHANG Ke, MA Xuening, WU Xiaomin, ZHANG Yuanshuai
		Research purposes: Determine the type of composite retaining structure and investigate the stress and deformation of the structure is the core when the structure is set up in the existing subgrade. Based on the practical engineering, field tests at different construction stages are carried out to study the combined force and deformation law to analyze the cooperative bearing mode of the structure. Research conclusions: (1) The earth pressure on the back of the pile-sheet wall increases with the distance from the pile top, and the earth pressure adjacent to the cantilever retaining wall increases first and then decreases and finally increases. The earth pressure behind the pile decreases first and then increases. (2) With the increase of filling height, the bending moment of pile increases first and then decreases with the increase of distance from the top of new pile, and the pile displacement decreases with the distance from the new pile top. (3) The simplified force model of composite structure is proposed from the measured data. (4) The study can provide technical support for the application of the composite structure in the railway subgrade widening project.
		2024 Vol. 41 (9): 1-6 [Abstract] ( 4 ) HTML (1 KB) PDF (1997 KB) ( 0 )

	7	Study on Calculation Method of Pile-soil Stress Ratio of Bidirectional Reinforced Composite Foundation
		ZHANG Sifeng, SUN Yafeng, LIU Qian, FAN Wei, LONG Guanxu
		Research purposes: Pile-soil stress ratio is an important index to reflect the working characteristics of bidirectional reinforced composite foundation. Due to the complexity of the bearing deformation mechanism of bidirectional reinforced composite foundation under embankment load, this paper takes the embankment and bidirectional composite foundation in the range of double piles as the research object. Considering the combined effects of multiple effects such as embankment soil arching effect, reinforced layer mesh effect and stress diffusion effect, a two-dimensional theoretical analysis model of embankment-horizontal reinforced cushion-vertical pile-soil coordinated deformation is established to explore the influence of various influencing factors on pile-soil stress ratio.Research conclusions: (1) The pile-soil stress ratio decreases with the increase of filling weight and pile spacing.With the increase of the internal friction angle of the filler, it increases first and then decreases. It increases with the increase of embankment filling height, the number of grid layers and the cohesion of filler. (2) The sensitivity of pile-soil stress ratio to each parameter from high to low is: pile spacing, embankment filling height, embankment filling weight, embankment filling cohesion, grid layer number and embankment filling internal friction angle. (3) The research results can provide theoretical basis and engineering reference for the calculation of pile-soil stress ratio of similar projects.
		2024 Vol. 41 (9): 7-8 [Abstract] ( 5 ) HTML (0 KB) PDF (841 KB) ( 0 )

	15	Numerical Simulation of Subgrade Compaction under Influence of Water Content
		CHANG Jianmei, DENG Xiaoling, ZHAO Hui, FENG Huaiping
		Research purposes: As a new technology, intelligent compaction has been successfully applied to subgrade engineering, which brings great convenience to construction. However, research and practice show that the failure to consider the influence of soil moisture content has become one of the main reasons that restrict the accuracy of intelligent compaction test results. Based on the method of resistivity measurement of soil moisture content, the test electrode is simulated to be installed on the vibratory roller's vibratory wheel. In this paper, the subgrade analysis model of soil fluid solid electric coupling is established, and the deformation, electric field distribution and evolution laws of soil under different soil moisture content and exciting force conditions are studied. Research conclusions: (1) The coupling equations of soil stress field, moisture field and electric field in the process of subgrade intelligent compaction are derived, and the numerical analysis model is established using COMSOL software, which provides an effective means for the analysis and research of subgrade intelligent compaction. (2) The compaction deformation of subgrade is obviously affected by soil moisture content. The subgrade settlement increases with the increase of water content. Increasing the exciting force can increase the compression deformation of the subgrade, but it takes a long time to achieve stability. (3) When the excitation force is increased, the final water content of soil decreases. The soil with lower than the optimum water content is the least affected by the excitation force. The soil with higher than the optimum water content is most affected by the excitation force. (4) The resistivity decreases with the increase of water content. With the same water content of soil, the resistivity and influence range of soil under larger excitation force are smaller than those under smaller excitation force. At the optimum water content, the effect of the exciting force on the resistivity is minimal. (5) The research conclusions can provide theoretical and practical support for the development and promotion of intelligent compaction technology of subgrade.
		2024 Vol. 41 (9): 15-21 [Abstract] ( 6 ) HTML (0 KB) PDF (1603 KB) ( 0 )

	22	The Shear Mechanical Characteristics of Soil-rock Mixture Using a Refined Discrete Element Method
		TU Yiliang, LI Jun, FANG Zhong, ZHOU Chengtao, ZHANG Lizhou
		Research purposes: Soil-rock mixture (SRM) is characterized by heterogeneity, nonuniformity, discontinuity and remarkable structural effect, and its physical and mechanical properties are very complex. In order to explore the influence of rock block proportion on the shear properties of soil-rock mixture, a discrete element numerical model of soil-rock mixture was established based on the real shape of rock blocks and the reverse reconstruction of rock block using digital image method. On this basis, the three-dimensional discrete element direct shear tests of six rock contents samples under four different normal stresses were carried out. Research conclusions: （1）The shear stress-shear displacement curves can be divided into four phases including elastic, initial yield, peak strength and residual strength. （2）In the process of shearing, the rotation of block stones has obvious "gear driving effect", the movement of soil particles has an obvious "rock around" phenomenon, and the movement of particles has an obvious vortex shape. （3）The force chain is mainly distributed along the angle between shear force and normal force. With the increase of rock content, the angle of the force chain towards the horizontal shear direction increases. （4）The evolution of shear plane mainly goes through micro crack stage, shear plane penetration stage, and shear band widening stage. The width of shear band increases with the increase of rock content, and gradually deflects counterclockwise. （5）The shear strength of soil-rock mixture increases with the increase of rock content. Through the fitting formula, the cohesion and internal friction angle are exponential functions with the rock content.（6）The research results can provide reference for the determination of mechanical parameters in the design and construction of SRM engineerings.
		2024 Vol. 41 (9): 22-29 [Abstract] ( 3 ) HTML (0 KB) PDF (4324 KB) ( 0 )

Main Line: Bridge Engineering

	30	Fire Resistance and Design of Composite Box Girder with Corrugated Steel Webs and Steel Bottom Plate
		CHENG Haigen, SHEN Qiang, ZHENG Shangmin, GUAN Chong
		Research purposes: In recent years, the increase in traffic volume has raised concerns about bridge fires resulting from vehicle collisions or the transportation of flammable materials. To understand the fire response of composite box girder with corrugated steel webs and steel bottom plate, a three-dimensional thermal-mechanical coupling analysis model was developed using ANSYS. This model analyzed the temperature field distribution and the decay of flexural bearing capacity under fire conditions. Additionally, it examined the impact of various fire scenarios on the fire resistance limit of the composite box girder and proposed fire-resistant design methods. Research conclusions: (1) The flexural bearing capacity of composite box girders under fire conditions progresses through three stages. The mid-span deflection, across various fire lengths, develops in two stages over time. As the fire length increases, the deflection growth rate of the composite box girder becomes more significant, with a more pronounced thermal bending effect during the initial fire stage. (2) Using the deflection failure criterion to determine the fire resistance limit of composite box girders is safer than using the resistance criterion. (3) Adding various types of stiffeners to the bottom plate of composite box girders improves their fire resistance limit. With the same amount of stiffener material, local stiffeners on the bottom plate enhance the fire resistance limit more effectively than continuous stiffeners. (4) The research findings can provide a reference for the theoretical analysis and fire-resistant design of composite box girder with corrugated steel webs and steel bottom plate.
		2024 Vol. 41 (9): 30-35 [Abstract] ( 5 ) HTML (0 KB) PDF (1962 KB) ( 0 )

	36	Practical Calculation Method for the Overall Stability of High-pier Rigid Frame Bridges Considering the Effect of Tie Beams
		LAN Shuwei, ZHOU Donghua, CHEN Xu, WANG Daohang
		Research purposes: Tie beams are often installed between the columns of high-pier rigid frame bridges. Currently, the calculation of the overall stability of high-pier rigid frame bridges mainly includes the calculation length coefficient method and the finite element method. The calculation length coefficient method for each component checking cannot consider the influence of different tie beam segments between the bridge piers. As the calculation theory and method are implicit in software, how to verify the accuracy and reliability of the calculation results in the finite element method is a difficult problem that must be solved. Therefore, based on force characteristics of the rocking column in this paper, the second-order calculation for solving the overall stability critical bearing capacity of high-pier frame bridges is transformed into the first-order problem to determine the overall lateral stiffness of structures through the concept of structural conversion. Research conclusions: (1) A calculation method for the critical force of the overall stability of high-pier rigid frame bridges is provided by calculating the structural lateral stiffness in this paper. (2) This paper provides a calculation formula for the critical force of the overall stability of column-typed high-pier rigid frame bridges. This formula can consider the influence of beam ties between column piers, compensate for the shortcomings of the standard calculation length coefficient method, and has good accuracy and precision. It can provide an analytical verification method for checking the reliability of the overall stability of the finite element calculation results. (3) The research results can be used for bridge engineering design and theoretical calculations.
		2024 Vol. 41 (9): 36-41 [Abstract] ( 4 ) HTML (0 KB) PDF (780 KB) ( 0 )

	42	Reinforcement Technology on Short-span Bridges for Heavy-haul Railway Based on the Method of Adding Supports
		CHEN Shuli, ZHANG Jiangong, TIAN Bo, XIE Kaize
		Research purposes: The short-span bridges are an important component and weak link of heavy-haul railway transportation. The service performance of short-span bridges is easily affected by axle load of freight train, making it difficult to meet the needs of capacity expansion of heavy-haul railways. Taking the common short-span bridge with a span of 12.0 m as an example, a simple reinforcement method for short-span bridges by adding vertical supports to change the structural system is proposed to improve the bearing capacity. Combined with numerical simulation and actual bridge test, the influence analysis of reinforcement parameters and the study of static and dynamic adaptability before and after reinforcement of short-span bridges are carried out, and reasonable reinforcement parameters are determined. Research conclusions: (1) The basic principle of adding support reinforcement method is to add vertical supports on both sides of the original supports of short-span bridges. By reducing the bridge span and changing the bridge system structure, the internal stress of the bridge is reduced, thereby improving the bearing capacity and service conditions. (2) The reasonable value for adding vertical support stiffness is 50% of the original support stiffness, and the reinforcement distance should be installed at the edge of the pier cap. The longitudinal width of the added support should be consistent with the original support. (3) After adding support reinforcement, the static and dynamic performance indicators of the bridge structure, such as mid span deflection, lateral vibration acceleration and vertical amplitude, as well as vertical displacement of the support, have significantly improved, with a reduction of more than 20%. The improvement degree of lateral amplitude and vertical acceleration of the bridge is slightly small. (4) The reinforcement method proposed in this paper can provide reference for the strengthening and maintenance of existing railway bridges.
		2024 Vol. 41 (9): 42-48 [Abstract] ( 6 ) HTML (0 KB) PDF (1003 KB) ( 0 )

	49	Key Pushing Construction Technologies for High-speed Railway Steel Box Girders with a Single Mid-span Temporary Pier
		LI Hao, LIU Longhua, LUO Jinhong, JU Chenxing, ZHANG Wenxue
		Research purposes: During the pushing construction process, the small-angle skew intersection between the new and existing lines causes difficulties in arranging temporary piers at the crossing sections and results in large cantilever spans of the main girder. This increases construction difficulty and challenges the safety of the construction. To address this issue, based on the Guangzhou-Shanwei High-speed Railway overpass on the Shenzhen-Shantou West Expressway,through Midas finite element simulation analysis and monitoring of stress and displacement in the actual bridge, the key technologies for pushing construction of high-speed railway steel box girders with a single mid-span temporary pier were studied. Research conclusions: (1) The pushing construction scheme without a temporary mid-span pier does not meet construction requirements. (2) The single mid-span temporary pier pushing scheme ensures that the stress and displacement of the main girder are within safe limits during the pushing construction process, meeting construction requirements. (3) The alignment and stress state of the completed bridge met the design expectations. (4) In small-angle skew pushing construction where temporary piers cannot be set up on the road, the single mid-span temporary pier pushing scheme can be used as an alternative. The construction and monitoring methods discussed in this paper can provide a reference for similar projects.
		2024 Vol. 41 (9): 49-54 [Abstract] ( 4 ) HTML (0 KB) PDF (868 KB) ( 0 )

Main Line: Tunnel Engineering

	55	Study on Adaptability of Initial Support of Tunnel in High Stress Horizontal Strata
		YUAN Tie
		Research purposes: The tunnel strata in Yichuan County of Menghua Railway are mostly horizontal sand and mudstone interbedded strata, the regional horizontal in-situ stress is high, under the joint action of in-situ stress and horizontal rock strata, the initial support of the tunnel occurs in a large area of peeling, cracking, falling blocks, and steel frame distortion, which brings greater safety hazards to the construction, and what type of measures to take for the high geostress horizontal rock strata is a problem that needs to be studied urgently. The four types of support types of conventional support, reinforced support, reinforced floor + long anchor, and limited resistance and energy dissipation support were studied. Combined with the 3DEC discrete element software and the actual deformation stress force measurement data in the field, the effects of the four types of support were compared and analyzed, and the engineering measures for rock strata with high geostress level were obtained. Research conclusions: (1) The cracking of the rock layer with high geostress level is mainly reflected in the peeling of the shotcrete of the vault, the falling of blocks and the distortion of the steel frame. (2) The single reinforced support parameter scheme and the reinforced bottom plate + long anchor support scheme have the effect on controlling the deformation convergence, but the arch still has the phenomenon of cracking and falling blocks, which cannot completely solve the construction safety risk. (3) The resistance-limiting energy-dissipating support can achieve the effect of releasing the pressure of the surrounding rock, and the initial support does not crack after the deformation of the resistance-limiting structure. (4) The use of resistance-limiting energy-dissipating support in rock formations with high geostress levels has achieved remarkable results in economy and safety, and the promotion and application effect is good.
		2024 Vol. 41 (9): 55-59 [Abstract] ( 3 ) HTML (0 KB) PDF (1362 KB) ( 0 )

	60	Experimental Study on the Diffusion Performance of Clay Shock Slurry in Shield Tunnel Construction
		ZHANG Zhiqiang, ZHANG Kangjian, CHEN Hao
		Research purposes: Clay shock method has gradually been introduced for auxiliary construction in the engineering of shield tunneling adjacent to existing structures. The diffusion performance of clay shock slurry in the stratum has a significant impact on the grouting effect behind the middle shield shell. Based on the self-developed grouting diffusion test system with constant-pressure for clay shock slurry, experiments were conducted to investigate the effects of water-powder ratio of liquid A, net grouting pressure, and permeability coefficient of stratum on the diffusion performance of slurry in the stratum, including final slurry amount, grouting end time, and diffusion distance. Combining the Bingham fluid diffusion model in sand, the theory and experimental diffusion distances of slurry were compared, and the reliability of the model test system and test results were verified. Research conclusions: (1) The yield stress and plastic viscosity of the clay shock slurry first increase and then decrease with the increase of the water-powder ratio of liquid A, and reach a local maximum value at the water-powder ratio of 3.0. (2) The diffusion behavior of clay shock slurry in soil shows a significant difference between filling diffusion and penetration diffusion. The filling diffusion stage mainly occurs in the first 30 seconds of injection, and can reach 70%-80% of the final slurry amount. The injection of slurry during penetration diffusion stage is slow, which closely related to the grouting end time. (3) As the water-powder ratio of liquid A increases, the final slurry amount and grouting end time first decrease and then increase, and as the net grouting pressure increases, the final slurry amount and grouting end time both increase. The diffusion distance of clay shock slurry is negatively correlated with slurry viscosity and positively correlated with net grouting pressure. (4) The influence of the diffusion distance is as follows: permeability coefficient of stratum > water-powder ratio of liquid A > net grouting pressure. (5) The results of this study can provide references for the engineering application and construction parameter selection of the clay shock method.
		2024 Vol. 41 (9): 60-66 [Abstract] ( 7 ) HTML (0 KB) PDF (1860 KB) ( 0 )

	67	Analysis on Diffusion Law of Synchronous Grouting Slurry in Shield Tunnel Based on Random Fracture Distribution of Surrounding Rock
		WANG Xinqiang
		Research purposes: Synchronous grouting in shield tunnel construction is a primary factor for segment floating and misalignment during the construction phase, particularly in geological strata characterized by poor self-stabilization and abundant fractures. This study aims to investigate the filling and diffusion behavior of synchronous grouting slurry within the tail clearance of a shield tunnel and its surrounding rock. A transient model of slurry permeability incorporating the random fracture distribution of the surrounding rock was established against the backdrop of the Guangzhou Metro Line 18, intending to provide theoretical guidance for the synchronous grouting process in shield tunneling. Research conclusions: (1) The grouting slurry can completely fill the shield tail clearance within 20 seconds post-grouting, subsequently permeating into the strata along the fractures with a seepage velocity that decreases over time. (2) Due to the presence of grouting pressure, the pore water pressure around the segment significantly exceeds that at the same depth further from the tunnel area. (3) The Darcy velocity within the fractures is considerably higher than in the continuous stratum, with permeating fractures serving almost exclusively as the conduit for groundwater flow. (4) The Darcy dynamic velocity within the strata is sensitive to both the porosity and permeability coefficients. (5) The research findings are applicable to the field of grouting engineering in shield tunneling.
		2024 Vol. 41 (9): 67-71 [Abstract] ( 5 ) HTML (0 KB) PDF (1377 KB) ( 0 )

Main Line: Electrification Engineering

	72	Precise Location Technology of Tracks Station Catenary Fault Based on Current Direction
		LI Zhe
		Research purposes: The catenary of the electrified railway station and yard hub has complex structure and numerous branches. Once a fault occurs, manual inspection can only be relied on to find the fault point, which is time-consuming and laborious. To solve this problem, current detection sensors are installed on the nodes of the substation outgoing line and the catenary of each branch track to detect and calculate the current amplitude and direction. Accordingly, an accurate fault location method for station and yard catenary based on current direction is proposed in this paper. Research conclusions: (1) The current amplitude of the grid point on the outgoing line can determine whether there is a fault in the station and yard hub. Once the fault is found, the monitoring computer collects the current waveform sampled by all current detection sensors, and the occurred fault information uploaded by the edge current sensor. (2) Once the fault is found on the edge current sensor, the fault section is in the outside of the sensor. (3) The current angles of each adjacent sensors are calculated, and the current directions of the catenary are obtained. Once the opposite direction current is found, and the fault section can be determined. (4) The research results can be applied to the precise location of the fault catenary in electrified railway station and yard hub, and are suitable for the field of traction power supply.
		2024 Vol. 41 (9): 72-76 [Abstract] ( 7 ) HTML (0 KB) PDF (587 KB) ( 0 )

Information Technology

	77	Research on BIM Intelligent Temperature Control System and Method for Mass Concrete
		WANG Wei, LIU Xingfu, LIU Ailin
		Research purposes: For the problem that the mass concrete of the ultra-high main tower is prone to crack due to the excessive temperature of the concrete in the construction process, BIM intelligent temperature control system and the method are studied, the REVIT software is selected for modeling and secondary integrated development with big data platform, and the intelligent temperature control system is established by using 4G wireless network communications equipment, industrial integration server and computer software. Moreover, it is equipped with artificial intelligence control algorithm to make advance prediction and intelligent decision of the whole process temperature of mass concrete. Research conclusions: (1) The temperature monitoring subsystem of mass concrete raw materials and outgoing machine, and the temperature monitoring subsystem of concrete mold entering and hardening process are established, which can dynamically monitor the temperature of the whole process of concrete construction through 4G wireless transmission and reception of temperature measuring element data. (2) The position of temperature measurement points is marked in the BIM model and the temperature change is visually reflected synchronously, and the overrun warning is carried out. (3) Advance prediction and intelligent decision are made on the temperature of outgoing machine, entering mold and hardening process of mass concrete, and a series of decision methods are provided such as raw material temperature control and water-cooling system control to ensure that the temperature of construction process meets the specification requirements. (4) The control system and method have been applied in the mass concrete temperature control of the ultra-high main tower of the Yangtze River Bridge with highway and railway in Ma 'anshan, and achieved good application results.
		2024 Vol. 41 (9): 77-80 [Abstract] ( 6 ) HTML (0 KB) PDF (1257 KB) ( 0 )

	81	A High Identification Image Acquisition Method for Suspension String Based on Machine Vision and YOLOv5
		XU Jianguo, HAN Jianmin, LIU Yan, WANG Jianchao
		Research purposes: To address the issues of low efficiency, low accuracy, and high investment cost in high-definition image acquisition and detection of the overall suspension string of high-speed rail overhead contact system, a high-definition acquisition method for the overall suspension string based on front-end image recognition triggering and deep learning algorithm fusion localization is proposed. Research conclusions: (1) Using an embedded FPGA+ARM dual processing platform, the YOLOv5 based suspension string positioning algorithm is embedded in the hardware structure. Image processing hardware acceleration and recognition filtering are achieved through FPGA, and high-precision recognition of image data is achieved through ARM. The overall suspension string image detection rate is 99%, with a detection time of 4 ms per image, meeting the requirements of real-time detection. (2) By combining FPGA and ARM, a dedicated image processing algorithm chip is built-in to filter out a large number of useless images and obtain clear overall suspension string images. The accuracy and recall rate trained and tested on the dataset are 100%, and the actual circuit is greater than 99%. (3) By integrating the embedded FPGA+ARM hardware system with YOLOv5's suspension string positioning algorithm, the system detection cost has been reduced and the technical application scope has been expanded. This has a reference value for promoting high-quality intelligent construction and intelligent operation and maintenance of overhead contact system.
		2024 Vol. 41 (9): 81-86 [Abstract] ( 6 ) HTML (0 KB) PDF (1307 KB) ( 0 )

Urban Rail Construction

	87	Deformation Control of Shield Short-distance Crossing Existing Tunnels in Silt Reclamation Stratum
		ZHANG Wenlong, LIU Hua, HU Yazhou, LIU Renpu, TAN Qianyuan, XIE Nan, YE Weitao
		Research purposes: This study aims to ensure deformation control of a newly constructed shield tunnel crossing above an existing tunnel with short distance in silt reclamation stratum during both construction and operational phases. Based on the construction case where Line 5 of the Shenzhen Metro crossing above Line 11, a series of numerical simulations were employed to evaluate different soft stratum reinforcement schemes. Consequently, the corresponding deformation control strategies were proposed, and the effectiveness of the reinforcement scheme was verified through deformation monitoring during the construction process. Research conclusions: (1) The reinforcement scheme of the ground jet grouting pile based on improving the long-term anti-deformation ability of tunnels is proposed. It shows that the effect of the increase of the width on the horizontal convergence of the tunnel is not obvious when the reinforcement width is greater than 5 m. (2) Compared with the unreinforced case, the floating deformation of existing underlying tunnels and surface settlement are reduced by 44% and 86% after reinforcement, respectively, which can meet the deformation control requirements during the construction period. (3) The measured data of the construction period shows that the maximum floating deformation of existing tunnels is 3.2 mm, and the maximum surface settlement along the line is 5 mm, which meets the deformation control requirements, indicating that the proposed stratum reinforcement measures are effective. (4) The research results have certain reference significance for the construction of shield tunneling crossing existing projects in silt reclamation stratum.
		2024 Vol. 41 (9): 87-91 [Abstract] ( 4 ) HTML (0 KB) PDF (1325 KB) ( 0 )

Engineering Machinery

	92	Performance Prediction of Roadheader by PSO-SVR Algorithm
		FU Helin, ZHAO Yibo, WANG Lizhi, GUO Hongyu, LI Jie, DENG Huangshi
		Research purposes: The roadheader works as an indispensable mechanical equipment in the milling and excavation method. Its working performance is often constrained by the characteristics of surrounding rock and mechanical equipment conditions. To predict the working performance of roadheader, this paper takes the instantaneous cutting rate (ICR) as the evaluation index, comprehensively considers the surrounding rock factors and mechanical equipment factors, and establishes an ICR prediction system based on different algorithms. The support vector machine algorithm based on particle swarm optimization (PSO-SVR) is optimized, which supported the ICR prediction system. This system can efficiently predict the working performance and excavating speed of tunnels excavated by roadheader. Research conclusions: （1）The data of tunnels excavated by roadheader are used for the training samples of 5 different algorithms. The PSO-SVR algorithm has the best prediction accuracy. （2）The particle swarm optimization is used to search the optimal penalty coefficient C and kernel function coefficient g, which can effectively avoid falling into local optimal solution and significantly improve the prediction accuracy and generalization ability of the model. （3）The ten-fold cross validation results indicate that the PSO-SVR model has better robustness than that of the other four algorithms. （4）Based on the Ganzhou Rongjiang Tunnel, the ICR and excavating speed of the roadheader is accurately predicted by PSO-SVR model, whose prediction accuracy is significantly higher than the empirical formula and other four algorithms, providing reference for the selection of roadheader and the prediction of excavating speed of roadheader.
		2024 Vol. 41 (9): 92-98 [Abstract] ( 4 ) HTML (0 KB) PDF (965 KB) ( 0 )

Risk Management and Research

	99	Research on Safety Resilience Optimization of Railway Tunnel Construction in Complex and Challenging Areas
		WANG Hui, LIU Yanan, MENG Yang
		Research purposes: In response to the high difficulty of safety management and high risk of safety accidents in railway tunnel construction in complex and dangerous areas in the western region, this paper explores the use of safety barrier models as an effective means to block risk sources and prevent safety accidents. Improving the resilience of the construction safety management system itself is an important goal to ensure the safe and reliable performance of the tunnel construction system. Research conclusions: (1) Based on the "4M" accident causation theory, a safety barrier model for railway tunnel engineering was established, and an Input-output Structural Model (ISM) was used to construct a diagram of defense elements. (2) The method of distance entropy was used to quantify data and calculates dynamic weights, and the resilience level of the safety barrier model wais measured by combining static Inoperability Input-output Model (IIM) and dynamic IIM. (3) A dynamic optimization system for safety barriers was established, dividing safety barrier warning levels to ensure system safety performance. (4) The research results can be applied in the K2 tunnel, achieving safety risk warning and rectification of safety hazards, improving safety resilience levels, and achieving safety risk control objectives.
		2024 Vol. 41 (9): 99-105 [Abstract] ( 6 ) HTML (0 KB) PDF (1002 KB) ( 0 )

	106	Study on Landslide Identification and Hazard after Construction of Railway Project in Mountainous Areas
		ZHANG Yu, LI Lei, HOU Yunlong, HAN Bingbing, AN Ning, ZHANG Hui, MA Ying
		Research purposes: Aiming at the difficulty of manual investigation and identification of landslide hazards along mountainous railway lines, a method is proposed to identify railway landslides based on remote sensing data and to quantitatively assess the scale and danger of railway landslides. Taking the Tanchang section of Lanzhou-Chongqing Railway as an example, PS-InSAR (Permanent Scatterers-Interferometric Synthetic Aperture Radar) technology and optical remote sensing images are used to identify the railway landslides in the study area, and based on ArcGIS and Massflow platform, the volume of landslides, whether they pose a threat to the railway are analyzed, in order to develop railway landslide mitigation strategies and ensure the normal operation of the railway after construction. Research conclusions: (1) Combining PS-InSAR technology and star map geo-optical remote sensing images to identify 2 potential railway landslides, and by analyzing the accumulated deformation of landslides, it shows that the potential landslides are obviously affected by rainfall. (2) The sliding surface of potential landslides is estimated based on ArcGIS platform using the tilted local datum method, and the maximum thickness of Linjiangpu landslide body is obtained as 9.9 m, and the volume is 3.1× 10⁴ m³; the maximum thickness of Huangjia landslide body is 12.9 m and the volume is 8.5×10⁴ m³. (3) The numerical simulation of the movement process of the two landslides is carried out using Massflow software, and the analysis results show that once damage occurs, the landslide body will impact the railway bridge deck, so it is recommended to focus on the prevention and control of potential landslides in Linjiangpu and Huangjia during the rainy season.（4）This study can be applied to railway safety monitoring and disaster prevention, and provide a scientific basis for landslide early warning and prevention in areas along mountainous railways.
		2024 Vol. 41 (9): 106-113 [Abstract] ( 4 ) HTML (0 KB) PDF (8725 KB) ( 0 )

Engineering Economy and Management

	114	Research on Optimization of Budget Quota Compilation for Mechanical Engineering of Railway Rolling Stock
		ZHANG Wenxiang, WEN Fangyu
		Research purposes: The budget quota for railway locomotive and vehicle mechanical engineering is an important component of the railway engineering quota system. It is used for the preparation of railway locomotive, vehicle, and mechanical engineering design estimates and plays a reasonable role in controlling investment. With the development of high-speed rail construction and technological progress, new requirements have been put forward for quota revision. This article analyzed the current application status of the 2017 edition of the budget quota for railway locomotive and vehicle mechanical engineering. Based on the principle of quota preparation, a new version of the quota preparation plan has been formulated, with optimized chapter settings and integration of green and low-carbon technology, which meets the requirements of the rapid development of high-speed railway. Research conclusions: (1) The new version of the budget quota preparation plan for mechanical engineering of locomotive and vehicle fully incorporates the latest experience in high-speed rail construction. For the first time, the installation of high-speed train maintenance equipment has been independently divided into chapters, and advanced maintenance procedures for high-speed trains have been added, filling the gap in the installation quota of high-speed train maintenance equipment and comprehensively showcasing the significant achievements of China's high-speed rail leading the world in recent years. It has strongly supported the construction of major high-speed railway projects along the "the Belt and Road". (2) Integrate carbon peaking and carbon neutrality into the quota. The focus is on adopting green and low-carbon technology, and the removal of coal-fired boilers reflects the requirements of green and low-carbon. (3) A large number of new equipment and technologies have been introduced, increasing the installation quota for detection station equipment, large-scale maintenance machinery maintenance equipment, and specialized equipment for rail welding bases. (4) Optimize chapter settings and reclassify and summarize maintenance equipment based on the main structure, maintenance processes, and procedures of locomotive and vehicle machinery, making the query method more user-friendly and improving the efficiency of quota query usage. (5) This article has a guiding role in compiling railway engineering quotas.
		2024 Vol. 41 (9): 114-117 [Abstract] ( 5 ) HTML (0 KB) PDF (757 KB) ( 0 )