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2023 Vol. 40, No. 3 Published: 2023-03-15

Urban Rail Construction Energy Saving and Environmental Protection Engineering Economy and Management Main Line: Engineering Geology and Subgrade Main Line: Railway and Rail Main Line: Bridge Engineering Main Line: Tunnel Engineering Main Line: Electrification Engineering Main Line: Research on Railway Networks

Main Line: Research on Railway Networks

	1	Evaluation of Comprehensive Traffic Development Level of Urban Agglomeration in China
		ZHANG Hang, LU Chunfang
		Research purposes: Urban agglomerations are the core carrier of China's economic development. Focusing on economic development advantageous areas such as central cities and urban agglomerations, thus driving the overall improvement of national economic benefits is a breakthrough direction for China's regional economic development. This paper aims to reasonably assess the development level of the city's comprehensive transportation system, clarify the development degree and gap of the current system, and guide the future direction of comprehensive transportation system development. Research conclusions: (1) The comprehensive transportation development level of the eight representative city agglomerations is: Yangtze River Delta Region, Guangdong-Hong Kong-Macao Greater Bay Area, Chengdu-Chongqing Twin Cities Economic Circle, Beijing-Tianjin-Hebei Region, Yangtze River Midstream City Cluster, Central Plains City Cluster, Harbin-Changchun City Cluster, Hohhot-Baotou-Erdos-Yulin City Cluster. (2) From the perspective of coordination, the Yangtze River Delta Region and the Guangdong-Hong Kong-Macao Greater Bay Area are high-quality coordinated development categories; The Beijing-Tianjin-Hebei Region, the Yangtze River Midstream City Cluster and the Chengdu-Chongqing Twin Cities Economic Circle are good coordinated development categories; The Central Plains City Cluster and the Hohhot-Baotou-Erdos-Yulin City Cluster are intermediate coordinated development categories; The Harbin-Changchun City Cluster is a primary coordinated development category. (3) The comprehensive transportation development of China's national urban agglomerations is relatively coordinated, and there is a certain imbalance in the transportation development of regional urban agglomerations, and the development of transportation systems in regional urban agglomerations should be paid attention to in the future.
		2023 Vol. 40 (3): 1-7 [Abstract] ( 2413 ) HTML (1 KB) PDF (788 KB) ( 1238 )

Main Line: Engineering Geology and Subgrade

	8	Research on the Stability Prediction of Dangerous Rocks on Railway Slopes Based on Intelligent Algorithms
		JIN Chunling, LIU Jingjing, GONG Li, CUI Wenxiang, LAO Zhengchang
		Research purposes: In railway construction and operation and maintenance, dangerous rock is a key problem in the prevention and control of geological hazards on side slopes. In order to achieve accurate and rapid prediction of the stability state of dangerous rocks on railway slopes and improve the accuracy of protection along railway lines, a new method of predicting the stability of dangerous rocks on railway slopes based on PCA improved GASA-FCM model (Genetic Algorithms Simulated Annealing C-Means, GASA-FCM) is proposed. The accuracy and superiority of the model are verified based on the Luoman-Mawei section of the Qiangui line. Research conclusions: (1) Considering the slope and dangerous rock condition, physical and mechanical properties of rock body and hydrogeological conditions, a railway slope dangerous rock stability prediction index system containing 13 secondary indicators is constructed. (2) Compared with the traditional FCM model and GA-FCM model, the GASA-FCM prediction model proposed in this paper has stable convergence value and smaller mean square error. (3) The model is used in the prediction and evaluation of the stability level of dangerous rocks in the slope of the Luoman-Mawei section, and the results are fully consistent with the actual survey results, which verifies the accuracy and superiority of the model. (4) The research results can provide reference for the prediction and evaluation of the stability level of dangerous rocks along other railway projects, which is of great significance to accelerate the information management of the whole railway line.
		2023 Vol. 40 (3): 8-13 [Abstract] ( 2355 ) HTML (1 KB) PDF (868 KB) ( 1214 )

	14	Upper Bound Analysis of Bearing Capacity of Reinforced Soil Retaining Walls under Strip Footing Load
		XU Peng, ZHONG Yi, MA Haoda, CHEN Lifang, LI Ting, YANG Guangqing, LIANG Xunmei
		Research purposes: Reinforced soil retaining walls (i.e. MSE walls) are light retaining structures and are widely used in civil engineering, for example railway and highway engineering. Reinforced soil retaining wall top is often constructed to support strip footing load in fields, such as reinforced soil abutment. Although the shape of failure surface is specified in the current design code of MSE walls, the value of bearing capacity (i.e. BC) for walls under strip footing load acting on the top surface is not given. Accuracy calculation of BC of reinforced soil retaining wall under strip footing load is of great significance to effectively ensure the stability of the wall in practical engineering. Based on the failure mechanism assumed in design code and the upper bound theorem, the upper bound solution of the BC of MSE wall is obtained. Research conclusions: (1)The results of the proposed method are in good agreement with those from model tests, and it shows good accuracy.(2)The value of BC decreases nonlinearly with the increase of footing width. (3)When the strip footing is far away from the wall facing, the value of BC is relatively greater. (4)Reinforcement length has little effect on BC if it is greater than 0.7 times of wall height.(5)When the vertical arrangement of reinforcement layer is tighter, the influence of reinforcement strength on BC is more significant.(6)The relationship between backfill strength and BC is approximately linear. (7)The research results are helpful to the design and application of reinforced soil retaining walls.
		2023 Vol. 40 (3): 14-19 [Abstract] ( 2331 ) HTML (1 KB) PDF (814 KB) ( 1090 )

Main Line: Railway and Rail

	20	Analysis of Smoothness of Ballastless Track on Long-span Partial Cable-stayed Bridge
		JIA Dongrong
		Research purposes: In order to investigate the influence factors on the smoothness of long and large-span partial cable-stayed bridges, the Changqing Yellow River Super-large Bridge is used as the object, and the external load factors of train load, overall warming of the main girder main tower, warming of the stayed cable and vertical temperature gradient of the main girder are considered, and a nonlinear static simulation model is established to analyze the influence of these factors on the ballastless track on large-span continuous girders, and based on the 60 m string measurement method, the influence of the combination of these factors on the amplitude of track unsmoothness is analyzed. Research conclusions: (1)Tower warming and cable cooling will reduce the amplitude of track unsmoothness under train load. (2) The coefficients of daylight temperature difference (along the girder height direction), tower and girder daily temperature difference and girder and cable temperature difference on track unsmoothness are 0.34 mm/℃, 0.18 mm/℃ and 0.13 mm/℃, respectively. (3) The formulae for the calculation of track unsmoothness amplitude under the effect of multiple working conditions including train load, main girder tower warming, stayed cable warming and main girder vertical temperature gradient are fitted. (4) The research results can provide reference for the research on the smoothness of ballastless track laid on super-long and long-span partial cable-stayed bridge.
		2023 Vol. 40 (3): 20-26 [Abstract] ( 2299 ) HTML (1 KB) PDF (1428 KB) ( 1055 )

	27	Research on the Track Expansion Value on Tied-arch Continuous Bridge for High-speed Railway
		HUANG Jie, XIE Haoran, LIU Congxin, YAN Bin
		Research purposes: In order to study the effect of temperature and live load on track expansion value on tied arch continuous bridge for four-line railway, the line resistance in ballast track was simulated with nonlinear bar elements (the method was already confirmed by UIC774-3 case), the integrated 3D model was established considering the concrete-filled steel tube arch, suspender, beam, bearing, pier, pile foundation, four-line track structure and track expansion device. Based on this, the distribution for track stress and deformation and pier-top horizontal force was analyzed in a variety of arrangements for track expansion devices. And it was explored that the arch, suspender and girder temperature variation, as well as combined cases of various braking bending forces made the impact on track expansion value and substructure. Research conclusions: (1) Track expansion device is set at side span mid-span to be able to greatly reduce track stress in the case of relatively small track expansion value. (2) The temperature variation of girder has a significant effect on the track expansion value, and the track stress can increase by 40 MPa after considering arch temperature variation. (3) The effect of braking bending force on the track expansion value is less, and the braking bending force peaks of load and no-load line appear in adjacent embankment segments when considering the multi-line load. (4) At the time of multi-line face-to-face load, the torque generated at the top of the pier can reach 8 033 kN·m. (5) The research results can provide a reference for the design of track structures on long-span arch bridges.
		2023 Vol. 40 (3): 27-32 [Abstract] ( 2327 ) HTML (1 KB) PDF (1021 KB) ( 1081 )

	33	Experimental Study of Train Running Safety on Steel Spring Floating Slab Track Used in Inner-city Rapid Rail Transit
		DING Deyun, MA Meng, WANG Wenbin, YAN Yuzhi, WU Zongzhen
		Research purposes: To investigate the dynamic behavior of steel spring floating slab track (SSFST) under different train speed, and analyze the train running safety when it is used in inner-city rapid rail transit at 160 km/h, eight steel spring floating slab tracks with a total length of 200 m were installed in a test railway line. In the test section, a train speed increased step by step from 60 km/h to 160 km/h. The track dynamic displacement and wheel/rail forces were tested on five sections, and the train running safety under different speeds was analyzed. Research conclusions: (1) When the train speed gradually increases to 160 km/h, all the safety indexes of steel spring floating slab track do not increase significantly with speed. (2) The vertical dynamic displacements on each steel spring floating slab track do not exceed 3.0 mm, and they decrease with the increase of train speed. (3) At different train speeds, the derailment coefficient is less than 0.3, the rate of wheel load reduction is less than 0.4, and the wheelset lateral force is less than 20 kN. There is safety redundancy for all the above aspects. (4) The present research can provide experimental support for the design and implementation of high-level vibration reduction measures for inner-city rapid rail transit.
		2023 Vol. 40 (3): 33-38 [Abstract] ( 2348 ) HTML (1 KB) PDF (1436 KB) ( 1015 )

Main Line: Bridge Engineering

	39	Research on the Model Tests of Intersection Section of Arch, Beam and Pier of Large-span Tied Arch Bridge
		WANG Chao
		Research purposes: Yibin Jinsha River highway-railway dual-purpose bridge is one of the important control projects of Chengdu-Guiyang line, as a highway-railway double-deck rigid frame tied arch bridge. The study object of this paper is the intersection region of the main arch, column, beam and pier of the bridge, the intersection section has the characteristics of many loads, large loads, different stress directions, and there are obvious stress concentration region. Through the comparative analysis of model test results and finite element analysis, the safety of the structure is evaluated, and reasonable suggestions for the design and construction are put forward, which provides reference for the design and construction of this kind of bridge. Research conclusions: (1) The detailed finite element analysis of the intersection section is carried out, and a 1 ∶6 scale model is designed and made to test the stress distribution, structural deformation and other stress characteristics of the model under the most unfavorable load conditions, as well as the bearing capacity under overload conditions. The results show that the structural design is reasonable and has a certain safety reserve. (2) It is suggested to add crack resistant reinforcement in the tensile area of the intersection section, strengthen the concrete vibration under the steel-concrete joint surface, and strictly control the bolt tension between the steel arch rib and the concrete arch seat to improve the construction quality. (3) The research results can provide reference for the construction of tied arch bridges of the same type.
		2023 Vol. 40 (3): 39-44 [Abstract] ( 2334 ) HTML (1 KB) PDF (1084 KB) ( 1200 )

	45	Research on the Monitoring Technology of High-speed Railway Bridge Based on Machine Vision Method
		LEI Dong, DU Wenkang, ZHU Guojing, LI Runpu
		Research purposes: Due to the closure and complexity of high-speed rail tracks, there are many restrictive factors in the process of detection, especially in high-speed rail bridges. Meanwhile, most of the existing management and maintenance technologies still rely on manual detection which consumes a lot of manpower and material resources, and limited detection efficiency. In this paper, a dynamic displacement measurement system based on machine vision is proposed to identify the structural deformation of high-speed rail bridges under operating conditions through field experiments. Research conclusions: (1) The dynamic displacement measurement system based on the machine vision method can better recognize the displacement changes of the structure and identify structural dynamic responses in the operating state. (2) The technology based on machine vision has many advantages such as non-contact, low cost, multi-point measurement and little interference to train operations. It can realize the monitoring of the structure state during non-"skylight" time, and improve the efficiency of management and maintenance. (3) The research results can meet the requirements of periodic inspection and long-term monitoring and provide significant support for the development of high-speed rail bridge inspection technology and the construction of health monitoring systems for high-speed rail bridges.
		2023 Vol. 40 (3): 45-49 [Abstract] ( 2357 ) HTML (1 KB) PDF (883 KB) ( 1173 )

	50	Running Safety of High-speed Railway Concrete-filled Steel Tube Arch Bridge under Extreme Temperature
		GOU Hongye, SU Zhenqian, WANG Junming, YUAN Wei, CHEN Zeyu
		Research purposes: In order to study the influence of the deformation of bridge structure under temperature load on the running safety on the bridge, taking a concrete-filled steel tube arch bridge of Chengzhou-Guizhou high-speed railway as the research object, a refined finite element model of long-span bridge-track is established based on ANSYS, and the deformation law of structure under the action of different temperature load is analyzed. On this basis, the finite element model of bridge-track structure is imported into SIMPACK for co-simulation, and the train-track-bridge coupling vibration analysis model is established. Finally, the variation rules of dynamic response indexes under different temperature loads and different speed are discussed from the aspects of train operation safety and comfort. Research conclusions: (1) The additional track irregularity caused by the upward deformation of the bridge is more unfavorable than the downward. (2) Under the effect of combined temperature, only wheel load reduction rate exceeds the limit of driving safety index, which is suggested to be taken as the main evaluation standard of running safety for high-speed railway. (3) Temperature gradient is an important reason for wheel load reduction rate exceeding the limit, and the effect of temperature gradient should be considered when analyzing the effect of temperature on train running safety in practical engineering. (4) The vertical Sperling index is very sensitive to the effect of temperature, and in order to ensure driving comfort, the speed of the train should be controlled when running under extreme temperature conditions. (5) The research results can provide reference for the driving safety evaluation of concrete-filled steel tube arch bridge.
		2023 Vol. 40 (3): 50-56 [Abstract] ( 2348 ) HTML (1 KB) PDF (907 KB) ( 1016 )

Main Line: Tunnel Engineering

	57	Deformation Responses and Control of Tunnel under Shield Shaft Vertical Jacking
		YANG Chunshan, MO Haihong, WEI Lixin, XU Shiyang
		Research purposes: In order to reveal the deformation response characteristics of the tunnel during the vertical jacking process of the shield shaft, the vertical jacking model test device was developed, and the jacking test was carried out to explore the reasonable damage range of overburden soil, the jacking reaction force and the tunnel deformation law in the jacking stage. The finite element method is used to analyze the deformation of the tunnel in the vertical jacking stage of the shield shaft, and the results are compared with the test results. The sensitivity of tunnel deformation to different reinforcement factors is discussed, and the idea of tunnel deformation control is proposed. Research conclusions: (1) The failure characteristics of the overlying soil layer in the vertical jacking stage do not follow the empirical assumption of the existing research, and the understanding of the failure mechanism and shape of the overlying soil layer in the existing research is insufficient, and the empirical calculation method of the jacking force proposed also has obvious errors. (2)The jacking force causes the outer opening and shear dislocation of the segment circumferential seam, and causes the inner opening of the longitudinal seam, and the longitudinal characteristics of the segment are more affected by the jacking force. (3)The opening amount can be reduced by using special segment in the open ring, but the shear dislocation trend between rings is aggravated, and the special segment is not suitable for practical engineering. (4)The deformation of the segment is inversely nonlinear with the stiffness of the ring joint, and the deformation tends to be stable when the stiffness increases by 5 times. In practical engineering, only the stiffness of the bottom joint between the rings is increased. (5)The grouting reinforcement outside the segment can effectively inhibit the tunnel deformation induced by the jacking construction, and the reasonable reinforcement range is 30° at the bottom of the segment. The existing results suggest that the circumferential reinforcement of 120°or all-round reinforcement is unreasonable, which causes waste and increases the construction risk. (6)The research results can provide reference for the application and promotion of vertical jacking construction method of shield shaft.
		2023 Vol. 40 (3): 57-63 [Abstract] ( 2372 ) HTML (1 KB) PDF (1302 KB) ( 1072 )

	64	Soil Disturbance Analysis and Settlement Control of Rectangular Pipe Jacking with Super Large Section
		JIANG Liutao, LI Hongbo
		Research purposes: The soil disturbance and settlement control in the construction of super-large section pipe jacking is very important to the risk control of the whole project. In order to explore the soil disturbance law and settlement control method of super-large section rectangular earth pressure balance pipe jacking, based on the pipe jacking project of Zhengzhou Hongzhuan Road crossing Zhongzhou Avenue, through the pipe jacking model and numerical solution analysis of soil settlement, the influence law of pipe jacking process parameters on soil deformation is deeply analyzed. Research conclusions: (1) The numerical solution of soil settlement under different factors of rectangular pipe jacking is consistent with the measured value, which verifies the accuracy of the numerical model solution. (2) Through the analysis of the influencing factors of soil disturbance, it is found that the friction coefficient of mud jacket has little influence on the ground settlement, and the proper increase of thrust and grouting pressure can inhibit the ground settlement. It is suggested that the thrust should be slightly greater than 1 time of the central earth pressure of the face, and the grouting pressure should be controlled within 2 times of the overlying soil pressure. (3) The comprehensive application of anti-back soil design, pipe joint wax coating, thixotropic mud, slag improvement, grouting and friction reduction, has a significant effect on reducing soil disturbance and settlement control of large-section pipe jacking. (4) The research results can provide reference for super-large section rectangular earth pressure balance pipe jacking engineering.
		2023 Vol. 40 (3): 64-70 [Abstract] ( 2339 ) HTML (1 KB) PDF (1249 KB) ( 1113 )

	71	Influence and Optimization of Blasting of Shallow-buried Tunnel on Sensitive Buildings
		FU Helin, JIANG Zhibo, QIU Qiong
		Research purposes: With the rapid development of urban subway construction, the construction requirements become more and more strict. At present, the existing research is mostly numerical simulation research, and the impact of the change of charging mode is less. The impact of the blasting construction of shallow-buried tunnels on sensitive buildings and the optimization control problem need to be solved. This paper takes the tunnel engineering of Chongqing Metro project as the background, and studies the optimal control of important buildings that need to be frequently crossed during the construction process and are extremely sensitive to the environmental impact. The comparison and analysis of different blasting media are calculated by theoretical derivation and verified by numerical simulation on site. The single hole charge of peripheral holes is optimized, the half hole retention rate is increased, and the blasting vibration speed is controlled. Research conclusions: (1) Compared with air medium, the eccentric uncoupled charge of water medium has more obvious control effect on the overbreak and under-excavation of surrounding holes.(2)The charge structure with radial decoupling coefficient ≥2 shall be used as much as possible for the peripheral hole charge of on-site construction.(3)Under the same conditions of other charging parameters, the radius diameter of the blasting area outside the surrounding rock (the charging deviation side) generally presents a continuous decline or stable change with the reduction of the surrounding rock grade, but the overall trend remains unchanged with the increase of the RQD value in the surrounding rock.(4) The maximum value of numerical simulation is higher than the maximum value of actual monitoring, because the model simplifies the geological conditions and ignores the energy loss of seismic wave propagation in rock joints and fractures.(5)After on-site implementation verification, the optimized blasting scheme can be used to control the impact of blasting construction of shallow-buried and underground excavation tunnels on sensitive buildings.
		2023 Vol. 40 (3): 71-78 [Abstract] ( 2357 ) HTML (1 KB) PDF (1399 KB) ( 1112 )

Main Line: Electrification Engineering

	79	Research on the Characteristics and Monitoring Methods of 27.5 kV Bus Voltage in Traction Substation
		CHU Zhenyu, ZHANG Changmei
		Research purposes: The 27.5 kV bus voltage of electrified railway traction substation is an important parameter of the power supply capacity and protection setting. Progressive failure of 27.5 kV bus voltage transformer often occurs in actual operation. But the existing bus voltage monitoring measures can not detect the progressive fault in time, which eventually leads to the protection action outlet tripping and the power loss of the whole bus, expanding the scope of the accident. It is necessary to study the characteristics and monitoring methods of 27.5 kV bus voltage in traction substation. Research conclusions: (1)The 27.5 kV bus voltage of traction substation is mainly affected by the capacity of traction transformer and system short-circuit capacity, of which the system short-circuit capacity has a greater impact. (2)The 27.5 kV bus voltage of high-speed railway traction substation has the characteristics of high no-load voltage and limited fluctuation range. The fluctuation range is basically between 24~29 kV from maximum load to no-load. (3)The monitoring method of 27.5 kV bus voltage value low alarm function and bus voltage transformer voltage difference high alarm function is proposed for electrified railway. (4) The research results in this paper can provide reference for identifying the bus voltage anomaly as soon as possible and ensuring the normal operation of traction substation.
		2023 Vol. 40 (3): 79-83 [Abstract] ( 2310 ) HTML (1 KB) PDF (689 KB) ( 1005 )

	84	Research on the Electric Field Measurement Method for Voltage Inversion of Overhead Line
		BAI Xiongxiong
		Research purposes: The voltage detection of overhead transmission lines in the power system is mainly based on voltage transformers, while the traditional transformers have the disadvantages of large volume, difficulty in moving, need to be installed without power, and possible ferromagnetic resonance, which makes the voltage monitoring of high-voltage transmission lines in areas with inconvenient terrain more difficult. Based on the electromagnetic field mirror method, this paper establishes the electric field calculation model of 110 kV three-phase overhead transmission line, and studies its electric field distribution characteristics. Then the feasibility of electric field measurement for overhead line voltage inversion calculation is demonstrated and a voltage inversion algorithm based on electric field sensor array is put forward, which can measure the three-phase electric field of wire. The voltage inversion of the scaled overhead line model is realized. Research conclusions: (1) Based on the electromagnetic field mirror method, the electric field calculation model of overhead line is established, and the electric field distribution characteristics of 110 kV three-phase overhead line are theoretically analyzed, and the results show that the field strength amplitude distribution of the ground below the overhead line is "bimodal". (2) Based on the research on the electric field distribution characteristics of 110 kV three-phase overhead lines, an overhead line voltage inversion algorithm based on three-phase electric field measurement is proposed, and theoretical analysis proves that by measuring the vertical three-phase electric field under the three-phase wire, the inversion calculation of the three-phase voltage of the overhead line can be carried out. (3)Based on the research of voltage inversion algorithm, a scaled model of 110 kV three-phase transmission line is built in the laboratory, and the accuracy of the algorithm is verified by experiments. The experimental results show that the amplitude error of the voltage inversion algorithm is within 3.31% and the phase angle error is within 2° for the established experimental model. (4) This research result can provide a theoretical basis for overhead line voltage monitoring.
		2023 Vol. 40 (3): 84-88 [Abstract] ( 2319 ) HTML (1 KB) PDF (1155 KB) ( 994 )

Urban Rail Construction

	89	Peck Empirical Parameters of Tunnel Surface Settlement Based on Measured Data
		ZHANG Jianquan, ZHANG Keli, YAO Aimin, YAN Yulei, CHENG Guifang
		Research purposes: The prediction model and parameters of ground settlement induced by underground engineering construction are not only closely related to the construction method, but also have great limitations due to the changes of regional geological conditions. In order to accurately determine the empirical parameters of the Peck model for the surface settlement of the underground excavation tunnel, the regional division is carried out according to the geotechnical parameters of the strata in different regions revealed by a large number of geotechnical engineering survey reports in Beijing, and based on the large data of the monitoring of the surface settlement of the mining method and the shield method in different regions, the theoretical calculation and regression analysis methods are used, the Peck formula prediction model parameters (settlement trough width parameter K and formation loss rate V_l) have been extensively inverted and analyzed, and the empirical parameters under typical geological conditions in different regions have been obtained, and the range of accurate parameters has been given, which can provide technical support for the prediction of surface settlement and deformation of underground excavation projects and the control of engineering safety risks in the region and similar geological conditions. Research conclusions: (1) The predicted parameters of the Peck formula for the surface settlement of the buried tunnel in the sandy gravel stratum in the west of Beijing, the medium-coarse sand stratum in the middle and the cohesive soil stratum in the east are as follows: the width parameter K of the shield tunnel settlement trough is 0.32~0.44, 0.34~0.51, 0.48~0.73, and the formation loss rate V_l is 0.60%~1.24%, 0.83%~1.38%, 1.28%~2.52%, respectively. (2) The appropriate range of Peck formula parameters for surface settlement of mining tunnel in the west, middle and east regions is as follows: the width parameter K of settlement trough is 0.29~0.44, 0.47~0.61, 0.59~0.70, and the formation loss rate V_l is 0.97%~1.51%, 1.13%~1.90%, 1.65%~2.00%, respectively. (3) The research results can be applied to the deformation prediction of surface settlement in the field of underground excavation under similar geological conditions.
		2023 Vol. 40 (3): 89-95 [Abstract] ( 2334 ) HTML (1 KB) PDF (982 KB) ( 1089 )

	96	Research on the Tunneling Parameters and Adaptability of EPB/TBM Dual-mode Shield in Composite Strata
		HE Chuan, HUANG Xing, CHEN Fan, SONG Tiantian, WU Chen, WANG Shimin
		Research purposes: For the purpose of exploring the excavation adaptability of EPB/TBM dual-mode shield in composite strata, based on the EPB/TBM dual-mode shield constructions between Huaide station and Fuyong station of Shenzhen metro line 12 and Liuxiandong station to middle shaft of Shenzhen metro line 13, this paper compared and analyzed the variation laws of tunneling parameters and energy consumption under different excavation modes, in order to provide references for similar projects. Research conclusions: (1) The EPB mode is used for soft soil strata to ensure the stability of the tunnel face, while TBM mode is used for the hard rock strata to avoid the risks of low tunneling speed and unexpected cutter head wear. (2) The variation law of tunneling parameters of EPB mode in soft soil strata is low speed, high torque, and high thrust, while high speed, low torque, and low thrust of TBM mode in hard rock strata. (3) The propulsion speed of the TBM mode in the slightly weathered stratum is about 38% higher than that of the EPB mode in the intermediary weathered stratum, and the proportion of effective excavation time increased by approximately 106.7%. (4) The energy consumption of EPB/TBM dual-mode shield has not increased significantly compared with EPB mode in soft strata. (5) The research in this paper can provide reference for the adaptability of dual-mode shield tunneling in composite strata.
		2023 Vol. 40 (3): 96-103 [Abstract] ( 2334 ) HTML (1 KB) PDF (1749 KB) ( 1161 )

Energy Saving and Environmental Protection

	104	Research on the Landscape Strategies of Railway Corridors from the Perspective of Landscape Ecology
		YAO Xuhui, HUANG Yan
		Research purposes: Based on the literature analysis of railway landscapes, this paper proposes an evaluation model of "ecology-landscape-perception" based on the theory of "landscape ecology" for the current research gaps, to evaluate and analyze the landscape object and the visual perception subject of railway corridor landscape. The evaluation indicators and methods for the coordination between the railway corridor landscape and the overall urban environment and the improvement of landscape comfort are discussed. It is of important theoretical and practical significance to build the railway corridor landscape into an ecological and comfortable traffic corridor. Taking Hangzhou-Huangshan Railway as an example, this paper conducts an empirical analysis on the evaluation research of railway corridor landscape based on the perspective of "landscape ecology". Research conclusions: (1) From the perspective of the theory of "landscape ecology", the subjective evaluation and objective evaluation of the railway corridor landscape are constructed into a systematic evaluation analysis method through the analytic hierarchy process. (2) The evaluation method adopted can realize the transformation from static single-point evaluation to dynamic linear evaluation of railway corridor landscape, and the evaluation coverage is wider. (3) The segmented evaluation is more conducive to landscape management and optimization for the current situation. (4) The research results have management and reference significance for the current railway corridor landscape evaluation and follow-up construction projects.
		2023 Vol. 40 (3): 104-109 [Abstract] ( 2319 ) HTML (1 KB) PDF (1044 KB) ( 1103 )

Engineering Economy and Management

	110	Research on the Evolution Mechanism and SD Estimation Method of Intelligent Construction Cost of High-speed Railway
		DUAN Xiaochen, MENG Yang, QIAN Rui
		Research purposes: The intelligent construction technology of high-speed railway is constantly innovating and developing. However, the existing linear cost estimation methods are gradually mismatched and inadaptable. In this paper, a nonlinear estimation system of high-speed railway intelligent construction cost is established by using nonlinear complex system prediction and other methods. Taking the intelligent construction cost of high-speed railway as the research object, the SD model of intelligent construction cost estimation of high-speed railway is established by exploring its influencing factors and their functional relationships, providing decision support for the optimization of intelligent construction cost control of high-speed railway. Research conclusions: (1) The random evolution law and trend of the actual cost of high-speed railway intelligent construction are analyzed and verified. (2) The structural equation analysis theoretical model of influencing factors of intelligent construction cost of high-speed railway are constructed, and the influencing factors of preliminary design estimate with universality are determined. (3) The current preliminary design estimate preparation method is reformed, the lag disadvantage of the current estimate and budget quota is shielded, and a basic database of high-speed railway intelligent construction is built based on near end historical data. (4) The SD model of intelligent construction cost estimation of high-speed railway is constructed. (5) The model established in this paper can provide decision support for intelligent construction cost management of high-speed railway.
		2023 Vol. 40 (3): 110-116 [Abstract] ( 2329 ) HTML (1 KB) PDF (1139 KB) ( 1104 )