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2022 Vol. 39, No. 9
Published: 2022-09-15
Engineering Economy and Management
Information Technology
Urban Railway Development and Technology Research
Main Line:Engineering Geology and Subgrade
Main Line:Railway and Rail
Main Line:Bridge Engineering
Main Line:Tunnel Engineering
 
       Main Line:Engineering Geology and Subgrade
1 Research on the Risk Identification and Assessment of Sudden Landslide in Loess Slope
CHENG Xiaowei, YAN Lizhen, LI Qingquan
Research purposes: In order to scientifically and quickly identify the risk of sudden landslide geological disasters on loess slope and prevent the occurrence of geological disasters, this paper studies the influencing factors, risk grade and weight which influence loess slope landslide, and the risk grade of sudden landslide geological disaster of loess slope under various influencing factors conditions, to provide reference for the prevention and control of geological diseases, win time for the elimination of diseases, also provide a basis for avoiding disease points, and prevent or reduce the casualties and property losses caused by geological disasters.
Research conclusions:(1) This paper constructs the risk identification and evaluation method of sudden landslide on loess slope based on comprehensive index method, clarifies the evaluation principles, puts forward 11 kinds of identification and evaluation index factors, give the weight of each index factor, and classifies the risk grade of each evaluation factor and the calculation results of the comprehensive index. (2) Through the example application and calculation, the evaluation results of this method are basically consistent with the actual situation. (3) For slopes (landslides) rated as "high risk" and "extremely high risk" by this method, early warning should be given and corresponding treatment measures should be taken to avoid or take measures in time. (4) This evaluation method can be applied to the evaluation and prevention of geological disasters in loess slope, and has reference significance.
2022 Vol. 39 (9): 1-6 [Abstract] ( 3925 ) HTML (1 KB)  PDF  (442 KB)  ( 1957 )
7 The Excitation Equipment Simulating Train Dynamic Action and Calibration Test
LUO Qiang, ZHOU Jianxiang, FENG Guishuai, ZHANG Liang, YI Mengbi, ZHENG Zhicheng
Research purposes: The dynamic effect of train load can cause elastic deformation and cumulative settlement of the subgrade, which can even lead to structural damage in serious cases. Build the vibration equipment based on a linear source biaxial motor. By adjusting the eccentric mass, device counterweight and input frequency, and regulating the vibration load output, this paper carries out calibration tests on the dynamic effect of the excitation equipment,analyzes the change rule of peak stress σp and valley stress σv relative to the static equilibrium stress σ0 with the eccentric mass and rotational speed of the motor, and discusses the upper and lower limit frequencies for the stable operation of the excitation equipment.
Research conclusions:(1) With the increase of the number of eccentric piece group i and vibration frequency f, the output dynamic stress σ of the excitation equipment is allometricl function growth trend, obeying the relation σ=Ai fBi, and dynamic equilibrium stress (σp+σv)/2 is greater than the static equilibrium stress σ0, the difference with the increase of f gradually expands. (2) The motor input frequency increases, the phase difference of the reverse rotation of the eccentric piece of the two-axis motor gradually decreases, and the error rate q and f of the vibration stress σpv=σp -σv relative to the static equilibrium stress σ0 are positively correlated. (3) Calibration test is carried out under the design dynamic load σpv≈100 kPa of the subgrade, and the deviation rate between the estimated and tested values of the fitted equation is in the range of -17.9%~8.7%. (4) The research results can provide a reliable basis for simulating the dynamic action of railway subgrade and understanding the dynamic characteristics of railway subgrade in the excitation test.
2022 Vol. 39 (9): 7-12 [Abstract] ( 3438 ) HTML (1 KB)  PDF  (835 KB)  ( 1878 )
       Main Line:Railway and Rail
13 Research on the Flexural Behavior of Assembled Long Floating Slab with High Performance Concrete Wet Joint
LI Qi, SONG Qingyuan, ZHENG Yue, DUAN Guiping, CHEN Gaofeng
Research purposes: In order to validate a new scheme of assembled long floating slab track connected by precast short slabs through wet joints using high performance concrete, static load tests and nonlinear finite element simulations are carried out to obtain the ultimate flexural capacity of the structure. On this basis, the numerical models with different diameters of steel bar, shape and strength of wet joint concrete are established and discussed to provide the reference for the design of the new floating slab.
Research conclusions:(1) The static load tests show that the ultimate flexural capacity of the floating slab is about 720 kN·m, which is basically consistent with the numerical simulation results and much larger than the design moment of the floating slab track. (2) With the reducing of the diameter of longitudinal steel bars in floating slab, the cracking load of the slab barely change, but its ultimate flexural capacity decreases, and the stress amplitude of the steel bars increases. (3) The joints of diamond and cuneiform shape have better performance than rectangular one. (4) The change of wet joint concrete strength has insignificant effect on the flexural capacity of the slab as long as the bonding strength between the concrete and steel bars is sufficient. (5) The research result can provide a basis for the design and application of the new floating slab track system.
2022 Vol. 39 (9): 13-18 [Abstract] ( 3358 ) HTML (1 KB)  PDF  (822 KB)  ( 1888 )
19 Historical Data Matching Method of Static Track Geometry Measurement andIts Performance Evaluation
WEI Hui, YANG Fei, WU Shifeng, ZHU Lei, YAO Hanxing, REN Xiaoyi
Research purposes: Historical data matching is the prerequisite and basis for data mining of orbital track geometric state. At present, matching based on external features is difficult to achieve sub-meter matching accuracy, and matching algorithms based on similarity are highly complex. To solve the above problems, this paper took static track inspection data as the research object, measured the similarity of data through dynamic time warping, and estimated the mileage deviation with the wrapped path, thus constructing an accurate matching method of static inspection historical data. On this basis, this paper discussed the matching performance evaluation, and introduced the synchronicity indicators on the basis of correlation and accuracy of the evaluation. Finally, the daily inspection data of a high-speed railway between January 15, 2021 and July 7, 2021 were used to verify the preceding matching method.
Research conclusions:(1) Compared with methods based on external features, the matching method described in this paper has better correlation, synchronization and accuracy. (2) Simulating maintenance operation by means of deforming the waveform, this method is robust to the maintenance operation and data loss. (3) This method is dispensed with external features, so it has the characteristics of low cost and good adaptability, and can be used for deep mining of track state information.
2022 Vol. 39 (9): 19-25 [Abstract] ( 3291 ) HTML (1 KB)  PDF  (1834 KB)  ( 1917 )
26 Resistance Characteristics and Size Optimization of Ballast Bed on Bridge
XIAO Jieling, XU Yi, JING Pu, QIAO Longxing, YU Sixin, LIU Junfeng
Research purposes: The discrete element simulation model of ballast bed on bridge is established and calibrated through full-scale ballast bed resistance test. We analyze the influences of section parameters such as width and thickness of ballast bed on ballast bed resistance, also discuss the influence range of transverse resistance and the sharing characteristics of each part of ballast bed on resistance. In order to reduce the second phase dead load and create conditions for bridge design, we put forward the optimization suggestions of ballast bed size on long-span bridge.
Research conclusions:(1) Within a certain range of width of the bed, the resistance increases with the top width increasing. When the top width increases from 3 400 mm to 3 800 mm, the increase rate of lateral resistance decreases from 16.9% to 4.6%, and the longitudinal resistance is less affected by the top width. (2) Within a certain range of thickness of the bed, the resistance increases with thickness increasing. When the thickness increases from 250 mm to 450 mm, the increase rate of lateral resistance decreases from 31.4% to 5.9%, and the increase rate of longitudinal resistance decreases from 18.6% to 4.0%. (3) The ballast within the width of 400 mm from the sleeper end is the main area to provide lateral resistance. (4) The resistance of ballast bed is mainly composed of the resistance of sleeper bottom, sleeper side and sleeper end, in which the lateral resistance of sleeper bottom is about 62%, sleeper side is about 14%, and sleeper end is about 24%. (5) Considering the resistance, economy and operation and maintenance requirements of ballast bed, it is suggested that the top width and thickness of ballast bed on bridge should be 3 400 mm and 300 mm respectively. (6) The research conclusions can provide a theoretical reference for the size optimization of ballast bed section on long-span bridges.
2022 Vol. 39 (9): 26-30 [Abstract] ( 3240 ) HTML (1 KB)  PDF  (489 KB)  ( 1898 )
       Main Line:Bridge Engineering
31 Research on the Longitudinal Stiffness of Pier and Temperature Span of High-speed Railway Integral Bridge
DAI Gonglian, CHEN Yanjie, DANG Kan, WANG Dezhi
Research purposes: The beam-rail interaction is closely related to the value of the design parameters of the high-speed railway internal bridge such as span layout and pier stiffness. When the values are not reasonable, the problems such as excessive deformation, instability and fracture of the rail on the bridge will occur. To ensure the safety of the lines on the bridge and obtain the value range and related relationship of the design parameters, this paper simulates the resistance of beam and rail based on the double-line and multi-segment broken lines, and establishes an equilibrium equation of the CWR to obtain the parameters like the additional stress and displacement of the rail. Combining rail strength, the relative displacement of beam and rail, displacement of pier top, rail gap width and rail stability, respectively, the relationship between the bridge temperature span and the piers' longitudinal stiffness and the value range are determined.
Research conclusions:(1) The temperature span and the piers' longitudinal stiffness are mainly affected by the rail strength constraint. The relative displacement of beam and rail, the displacement of the pier top, the rail gap width constraint and the stability of the rail have little influence. (2) The relevant calculation formulas for the two parameters of temperature span and piers' longitudinal stiffness under the limit of the code are put forward. (3) The algorithms and calculation formulas can provide a certain reference for the design of integral bridges.
2022 Vol. 39 (9): 31-37 [Abstract] ( 3994 ) HTML (1 KB)  PDF  (1148 KB)  ( 1975 )
38 Theoretical Solution on Spatial Mechanical Properties of Trapezoidal U-shaped Girders
WANG Genhui, GAN Ziyu
Research purposes: In this paper, the shear deformation and shear lag effect are considered comprehensively, and especially the self-equilibrium conditions for the shear lag warping stress and bending moment are introduced. Then the analytical solution of the vertical bending of trapezoidal U-shaped girder is obtained based on the energy variation method, the spatial mechanical behavior of U-shaped girder is studied in detail. And the validity of the analytical solution of this paper is verified by comparing with the numerical solution of finite element.
Research conclusions:(1) Relative to the neutral axis(x-axis), since the transverse asymmetry of trapezoidal U-shaped girder is prominent, so commonly used traditional shear lag theory is difficult to truly reflect the mechanical mechanism of this kind of structure without the introduction of self-equilibrium conditions about shear warping stress and bending moment. (2) Compared with the commonly used traditional shear-lag theory, the shear lag effect of U-shaped girder has no coupling relationship with the elementary beam theory, and its calculation accuracy is significantly improved. (3) The shear lag effect not only affects the normal stress of the bottom slab of U-shaped girders, but also on its web, which cannot be ignored. (4) If the cross-sectional dimensions of U-shaped girder is determined, its shear lag stress contribution to web and bottom slab is not affected by the span. (5) The method in this paper is a guide for the design of trapezoidal U-shaped reinforcement and prestressing tendons, and this in turn will improve its durability.
2022 Vol. 39 (9): 38-43 [Abstract] ( 3142 ) HTML (1 KB)  PDF  (558 KB)  ( 1911 )
44 Key Construction Technology of Steel Truss Girder with Complex Vertical Curve Crossing over Expressway
HU Kemin
Research purposes: The upper span of a rapid transformation project is a (165+90) m continuous steel truss bridge, which has the special characteristics of large span, complex vertical curve, and expressway keep passing requirement under the steel truss girder during construction. This paper studies the setting and structure of temporary piers suitable for the dragging construction of steel truss beams with complex vertical curves during construction, the lightweight design of steel guide beams, and the low-level over pier of nodes with external convex bases, to ensure the safety of the steel truss girder and the expressway during the construction.
Research conclusions:(1) The overall construction scheme of steel truss girder with sub assembly and less fulcrum support and sub dragging is proposed. (2) It is proposed to set up four dragging temporary piers during dragging. The structure of the temporary pier adopts a simple truss support, and the top line of the temporary piers is set as a circular curve according to the fitting of the vertical curve of the steel truss beam, so as to ensure the stress safety of the dragging construction. (3) The guide beam suitable for large-span single continuous launching is set. The length ratio of the guide beam to the steel beam is 0.38, and the weight of the guide beam is 70 kN/m. The guide beam realizes the continuous dragging of the long-span steel truss beam crossing over expressway at one time, reduced the construction time crossing over expressway. (4) A separated sliding block for the convex base outside the support node is designed to solve the problem of low-level over pier. (5) The research results can provide reference for the construction of steel truss bridges crossing over important expressway or existing railway lines.
2022 Vol. 39 (9): 44-49 [Abstract] ( 2980 ) HTML (1 KB)  PDF  (1413 KB)  ( 1933 )
50 Research on the Construction Control of Arch Rib of Concrete-filled Steel Tube Stiff Skeleton Arch Bridge
XU Hong, ZHOU Mi, WANG Yamei, XU Ruilong
Research purposes: In the large-span CFST stiff skeleton arch bridge, the stiff skeleton installation alignment directly affects the arch alignment. And if it is not controlled properly, it may even cause difficulties in the arch rib closure. Based on the project example of Yelang River Bridge, by the simulation analysis of the whole process of cantilever erection of arch ribs with cable-stayed buckle-hanging method, combined with the on-site internal force and real-time monitoring of alignment, the arch rib construction control technology of large-span stiff skeleton arch bridge is studied and analyzed.
Research conclusions:(1) In the cantilever assembly of the stiff skeleton, the arch rib alignment and the cable force were controlled, with the arch rib alignment being the main control. (2) In the simulation analysis, the vertical "0" displacement of the section was used to control the size of the cable force, and the vertical displacement was controlled within 1 mm error by adjusting the cable force and the elevation of the control point to obtain the cable force at this time. (3) Before the closure of the bridge, the joint test of the linear both sides and the whole bridge re-test were carried out. According to the monitoring results of the internal force and alignment of the arch ribs, the alignment and internal force of arch ribs were adjusted reasonably and effectively through the buckling cable and cable wind rope. (4) The construction control method of the arch rib proposed in this paper can effectively ensure that the arch alignment and structural stress meet the design and specification requirements, and it has reference value for the cantilever assembly and erection of the arch rib by the cable-stayed buckle-hanging method.
2022 Vol. 39 (9): 50-55 [Abstract] ( 2963 ) HTML (1 KB)  PDF  (675 KB)  ( 1940 )
       Main Line:Tunnel Engineering
56 Research on the Dynamic Response Characteristics of Soft Rock Tunnel Structure in High Seismic Intensity Area
LI Renqiang, MA Zhigang, YI Zhongqiang, ZHU Baolong, WU Honggang
Research purposes: In order to study the basic law of dynamic acceleration response of soft rock tunnel in high seismic intensity area under earthquake action, shaking table test of 1 ∶50 scale tunnel model was designed and carried out on the background of Jiedexiu No.2 tunnel project of Lasa-Linzhi Railway. Through input white noise, EL wave and the wave of Wenchuan, the dynamic response of model structure is tested, the change rule of peak acceleration amplification coefficient of various points with the change of height and different seismic intensity is analyzed, the power spectrum is obtained by fast Fourier change spectrum curve, the acceleration dynamic characteristics of the model structure are analyzed, the acceleration response curves in frequency domain under various loading conditions are compared, and the basic law of dynamic response in frequency domain of the model structure is studied.
Research conclusions:(1) The site elevation effect of soft rock tunnel in high seismic intensity area is different from that of general site. (2) With the increase of ground motion amplitude, the peak acceleration amplification coefficient of each measuring point shows a decreasing trend, and shows a maximum value under 0.15g acceleration excitation. The influence of seismic wave excitation with different frequency characteristics on the elevation effect form is basically the same, and the seismic response at the inverted arch is the largest. When conducting tunnel seismic fortification, the seismic measures at the inverted arch should be strengthened. (3) The amplification effect of surrounding rock soil on acceleration is obvious, but the amplification effect of tunnel lining structure on acceleration is not obvious. The response characteristics of stratum largely determine the seismic response characteristics of lining structure. (4) The power spectral density curve shows that the response peaks of the model structure under different seismic waves are similar, but the corresponding frequency values are different. The high frequency seismic waves have little influence on the lining structure, and the low frequency seismic waves have great influence on the lining structure. (5) The research results can provide a theoretical reference for the seismic design and construction of tunnels in high seismic intensity areas.
2022 Vol. 39 (9): 56-63 [Abstract] ( 3108 ) HTML (1 KB)  PDF  (2263 KB)  ( 1878 )
64 Research on the Ventilation Scheme of 3 Holes Parallel Construction in Subsea Tunnel
ZHU Zhengguo, SUN Aojie, CHEN Libao, SUN Wenhao, HAN Zhiming, SUN Minglei
Research purposes: At present, aiming at the diffusion law of harmful gas in drilling and blasting construction, there are more studies on single tunnel blind heading, but the ventilation scheme of 3 holes parallel construction is rarely studied. In order to explore the optimal ventilation scheme for the parallel construction of the three-hole subsea tunnel and optimize the fan arrangement, based on the second subsea tunnel in Qingdao-Jiaozhou Bay, this paper focuses on the pollutant transport law of 3 holes parallel construction in the drilling and blasting section in the sea area. In this paper, the 3D model of 3 holes parallel-double large section main tunnel + small section service tunnel-are established. The CO concentration distribution after tunnel blasting is simulated by the 3D turbulent RNG k-ε model and component transport model in FLUENT. And the variation law of CO concentration under three ventilation schemes is analyzed. On this basis, the distribution of cross channel jet fan is optimized.
Research conclusions:(1) Under the condition of 3 holes parallel construction, through the intermediate service tunnel, the pollutants produced by drilling and blasting construction of multiple working faces can be effectively discharged. However, there will be pollutant retention in the cross channel area. (2) After the jet fan is added into the service tunnel, there is no obvious CO retention in the whole process. And the concentration peak can be significantly reduced and the discharge concentration rate of CO can be accelerated. (3) The best position of jet fan is 10 m away from the center of cross passage. (4) The research results can provide reference for the design and construction of related subsea tunnel.
2022 Vol. 39 (9): 64-69 [Abstract] ( 3645 ) HTML (1 KB)  PDF  (1397 KB)  ( 1972 )
70 Research on the Difficulties and Countermeasures of TBM Tunnel Construction in Plateau Railway
LI Zhijun, HONG Kairong, CHEN Qiao, NIU Tongtong, ZHOU Yi, YU Jingbo
Research purposes: The Sejilashan Mountain Tunnel is a controlling project of Ya'an-Linzhi section of plateau railway. The complex geological conditions in the tunnel site area bring great challenge to the safe and efficient construction of TBM. This paper focuses on coping strategies for difficult problems such as high ground stress rock burst, long distance tunnel ventilation on the plateau, and synchronous construction of TBM boring and secondary lining, to ensure efficient TBM construction.
Research conclusions:(1) The steel pipe sheet is used to replace the steel arch support, and the steel pipe sheet installer is used to install the whole ring steel pipe sheet in the shield, so as to improve the initial support operation efficiency and support capacity of strong rock burst section. (2) Intelligent ventilation technology is adopted to effectively take into account the air quality of the tunnel and the energy consumption of fan operation. The combination of diffuse oxygen supply and emergency oxygen supply in office and living areas can meet the needs of nearly 800 people in the peak period. (4) The integrated pouring of secondary lining and low side wall and the synchronization of TBM excavation can alleviate the problem of tight construction progress of TBM tunnel. Each lining formation is equipped with two floating Y-shaped turnouts and one crossover, which can realize the "one machine and two tanks" transportation mode under four tracks and three lines, and meet the needs of continuous pouring of secondary lining. (4) The research results can provide a reference for other TBM tunnel projects in plateau railway.
2022 Vol. 39 (9): 70-78 [Abstract] ( 3438 ) HTML (1 KB)  PDF  (1507 KB)  ( 1976 )
       Information Technology
79 Challenges and Coping Strategies Faced by Digital Transformation of Construction Enterprises
HUANG Congzhi, XIAO Lei
Research purposes: The global economy is accelerating its transformation from an industrial economy to a digital economy. The digitalization level of the construction industry is at a relatively low level. Construction enterprises are facing great challenges in the digital transformation work. Combined with the digital transformation practice of construction enterprises, this paper studies the challenges and coping strategies in the process of digital transformation.
Research conclusions:(1) The current situations in the process of digital transformation of construction enterprises are analyzed, such as the weak digital foundation, the gradual slowdown of China's infrastructure investment, and the serious aging of construction workers. (2) It is proposed that construction enterprises are faced with challenges such as high digital requirements, fierce digital competition, unclear strategic goals and path planning for construction enterprises, and informatization capabilities difficult to cope with complex requirements. (3) The digital transformation response strategies of construction enterprises are proposed, such as carrying out top-level design benchmarking and table-targeted governance, creating a digital industry sector to integrate into the digital economy, promoting the intelligent upgrade of digital production, R&D, and manufacturing digital equipment, and combining upstream and downstream industries to carry out digital transformation. (4) The research in this paper can provide a reference for construction enterprises to carry out digital transformation work.
2022 Vol. 39 (9): 79-84 [Abstract] ( 3174 ) HTML (1 KB)  PDF  (767 KB)  ( 1978 )
85 Schedule Risk Analysis of Technical Interface between Railway Bridge and Four Electric/Electronic Systems Engineering
BAO Xueying, LI Yajuan, HU Suoting, BAN Xinlin, WANG Lin, XU Jianchao
Research purposes: In order to realize the optimization control of the project schedule of the railway bridge in arduous mountainous areas, the technical interface between bridge and four electric/electronic systems engineering is the main research body, the risk impact of the construction of the technical interface is considered, a risk analysis model of the implementation schedule of the technical interface coupling BBNs and CSRAM is constructed.
Research conclusions:(1) Identify the potential risks in the construction of technical interfaces between railway bridges in arduous mountainous areas and the four electric/electronic systems engineering, use BBNs to quantify the non-superimposed impact of the risk relationship on the construction progress of the technical interfaces, and calculate the probability boundaries of risk factors for the technical interfaces. (2) Use the CSRAM method to analyze the random variation of risk factors in the construction process of the technical interface and the relationship between the risk factors and the construction schedule; by coupling the BBNs and CSRAM method, use the Monte Carlo method to simulate the implementation schedule risk of the technical interface, and carry out sensitivity analysis on risk factors. (3) Taking the Yarlung Zangbo River Bridge and the four electric/electronic systems engineering in Rongxiang as an example, the progress simulation and sensitivity analysis of their technical interfaces are carried out, the results show that the completion date of the technical interface under the influence of risk is 644 days and the completion probability is 89.92%. The implementation of the technical interface management is the most sensitive factor affecting the construction schedule of the technical interface. (4) This research can provide reference for the schedule management of railway bridge technical interface in difficult mountainous areas.
2022 Vol. 39 (9): 85-92 [Abstract] ( 3270 ) HTML (1 KB)  PDF  (1057 KB)  ( 1911 )
       Urban Railway Development and Technology Research
93 Research on the Minimum Line Spacing and Curve Widening Method of Urban (Suburban) Railway
YU Baoxing
Research purposes: With the acceleration of China's urban integration construction process, the demand for urban (suburban) railway construction is gradually increasing, and the urban (suburban) railway has strict requirements in economy, practicality and functionality. Therefore, this paper studies the minimum line spacing, widening value and widening method of urban (suburban) railway, so as to optimize the line conditions and make rational use of limited resources.
Research conclusions:(1) The minimum line spacing of type A and B vehicles in the city does not need curve widening; The widening values of C and D vehicles in the city area are recommended to be selected according to the calculation results; The minimum line spacing of CRH2 train is recommended to be 4.2 m. (2) It is recommended to select the curve widening value of urban (suburban) railway according to the widening calculation results. (3) In the concentric circle widening method with constant line spacing, the curve radius is inversely calculated by rounding ten according to the transition curve, so that the most economical and practical circular curve parameters can be obtained and unique; This method is not affected by deflection angle. (4) The non-concentric circle widening method with variable line spacing is used according to the limiting conditions and MATLAB program to calculate the radius range of the second-line curve, and the most economical and practical curve elements are selected according to different working conditions; It is found that large deflection angle and small curve radius will reduce the value range of curve radius; The maximum line spacing of this method appears on the transition curve near YH (or near HY). (5) The research results have reference value for supplementing the Code for Design of Suburban Railway and reasonably optimizing resources.
2022 Vol. 39 (9): 93-99 [Abstract] ( 3703 ) HTML (1 KB)  PDF  (510 KB)  ( 1946 )
100 Analysis of the Influence of the Operation Proportion of Express/local Trains on the Setting of Overtaking Stations in Regional Rapid Rail Transit
XU Jun, LIANG Qinghuai, HAN Kuo, DENG Jingwei
Research purposes: Under the mode of express/local trains of urban express rail transit, the setting of overtaking stations affects the project investment, operation efficiency, and operation safety, which is one of the key problems in the planning and design of express/local train operation organizations. The number and operation proportion of express/local trains have an important impact on the setting of overtaking stations. This paper takes the operation organization design of express/local trains of Chongqing rail transit line 27 as an example, calculates and analyzes the influence of express/local train proportion on the line capacity, the number of overtaking stations, and the location of overtaking stations based on the overtaking station distribution calculation method. Suggestions are given for overtaking stations settings.
Research conclusions:(1) A smaller train proportion can better take into account the line capacity and the number of express/local trains. And a large train proportion can improve the line capacity, but the number of express trains will be lost. (2) The change of train proportion has little impact on the number of overtaking stations when the line capacity is certain. (3) By setting overtaking stations near the terminal stations, the line can better adapt to different operation ratios of express/local trains. (4) The research results can provide reference for the setting of overtaking stations and the design of the organization scheme of express/local trains in urban express rail transit.
2022 Vol. 39 (9): 100-105 [Abstract] ( 3161 ) HTML (1 KB)  PDF  (511 KB)  ( 1882 )
       Engineering Economy and Management
106 The Method of Price Adjustment Factor Determination Using Price Index in Railway Engineering
LI Jingjing, SHEN Qiangqiang, DING Lu, ZHANG Wei, ZHANG Feilian
Research purposes: The price adjustment caused by price fluctuation is the focus on railway engineering contract disputes, and it is also the key work to effectively control investment and create a fair and harmonious competition environment. Based on the basic idea of FIDIC contract price index adjustment method and the budget estimates of seven railway engineering projects in China, this paper explores the method of price adjustment factor determination using price index in railway engineering: selection of price adjustment elements - determination of the number of combination factors-combination of price adjustment elements.
Research conclusions:(1) According to the Pareto principle, the constituent elements of the first 50 material cost are selected as price adjustment elements. (2) The relationship between the number of different combination items and the adjustment rate of contract price is analyzed to determine the combination number of adjustment elements. The Monte Carlo simulation program is compiled by JAVA language. (3) Pearson product distance correlation coefficient of 0.98 is used as the threshold for a combination of price adjustment elements. (4) Based on the budget data and material price information on the case project, eight price adjustment factors of railway civil works are established. (5) The research conclusion has theoretical and practical reference significance of the selection and combination of railway engineering price adjustment elements and the construction of railway engineering prices index system.
2022 Vol. 39 (9): 106-111 [Abstract] ( 4022 ) HTML (1 KB)  PDF  (524 KB)  ( 1950 )
112 Cost Estimation Method for Overseas Railway Construction Project Based on Artificial Intelligence
DUAN Xiaochen, BAO Mo, NIU Yanliang, LEI Peijun
Research purposes: The investment estimation of overseas railway construction projects urgently needs a valuation system integrating reliable historical data and scientific estimation methods to solve the problem of project losses due to the low efficiency and accuracy of investment estimation. This paper uses nonlinear methods such as PSO (Particle Swarm Optimization) and BPNN (Back Propagation Neural Network) to establish an intelligent estimation model for overseas railway investment to make up for the shortcomings of traditional estimation methods such as strong subjectivity and low reliability.
Research conclusions:(1) 19 factors affecting the overseas railway investment estimation are identified, including construction market and geological conditions. (2) It is found that the nonlinear methods such as PSO and BPNN can be well applied to the study of overseas railway investment estimation. (3) Through empirical research, the error of the model established in this paper is controlled within 6.44%, with high accuracy, which can be popularized and applied to the investment estimation of subway and high-speed railway in China. (4) This research can provide reference for other overseas railway construction project cost estimation research.
2022 Vol. 39 (9): 112-118 [Abstract] ( 3205 ) HTML (1 KB)  PDF  (1001 KB)  ( 1909 )
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