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2022 Vol. 39, No. 8
Published: 2022-08-15
Main Line: Survey and Design
Main Line: Engineering Geology and Subgrade
Main Line: Railway and Rail
Terminal,Station yard and Building
Main Line: Tunnel Engineering
Main Line: Electrification Engineering
Urban Railway Development and Technology Research
 
       Main Line: Survey and Design
1 Research on the Key Technology of Ultra Long Directional Drilling in Railway Tunnel in Mountainous Area
XIE Yi, XU Zhengxuan, CHEN Minghao, ZHANG Guangze, FENG Tao, WANG Sheng, WU Jinsheng
Research purposes: The topographic and geological conditions of the mountainous area railway are extremely complex and changeable, and the engineering geological problems are prominent and hidden. In addition, the traffic is inconvenient, the people are rarely visited, the steep rock strata are widely distributed, the ecological environment is fragile, and the environmental protection requirements are high. Drilling is the most direct, accurate and effective tunnel engineering survey method. The implementation of traditional vertical drilling of railway tunnel is difficult, resulting in the blank of exploration data in long and large sections of tunnel, which seriously restricts the survey and design work, so it is urgent to carry out the research on ultra long directional drilling technology in railway tunnel, especially the key technology of ultra-kilometer horizontal hole rope coring directional drilling.
Research conclusions: (1) The ultra long horizontal hole rope coring directional drilling is an advanced drilling method of taking cores from the drill pipe without lifting the drill pipe string. It is the key technology for the investigation of long, deep buried railway tunnels in complex and dangerous mountainous areas. (2) Through the research on directional drilling methods and technologies, equipment and instruments, and green engineering materials, the directional drilling technology system of super long horizontal hole rope for core in railway tunnel is constructed. (3) The method and process of directional drilling for the core of super long horizontal hole rope in railway tunnel are established, and the longest horizontal hole drilling record in the history of railway survey in China is 1888.88 m. (4) The ultra long horizontal hole rope coring directional drilling technology studied in this paper has a broad application prospect in the Western Development, Transportation Power strategy and the the Belt and Road construction in the new era.
2022 Vol. 39 (8): 1-5 [Abstract] ( 4019 ) HTML (1 KB)  PDF  (1048 KB)  ( 1954 )
6 Discussion on Comprehensive Geophysical Exploration Model of Giant Deep Rock Landslides
SUN Honglin, HUA Xirui, ZHAO Jinqian
Research purposes: Giant deep rock landslides have the characteristics of complex genesis, large scale, and difficulties in investigation and processing. Due to the limitations of topographic and geological conditions and the applicability of geophysical methods, a single geophysical method often can't fully and effectively reveal the scope of landslides and the spatial form of sliding surface. In this paper, the exploration of the giant deep tuff landslide in Xiageliao was taken as an example. Based on factors such as geological conditions, exploration purposes, and exploration methods, the exploration model suitable for comprehensive geophysical exploration of giant complex rock landslides was studied.
Research conclusions: (1) It is very beneficial to adopt the comprehensive geophysical prospecting first survey procedure based on geological surveys for complex deep rock landslides. The physical detection line shall be laid out in a mesh along the main axis and the vertical slope. (2) High-frequency magnetotelluric method, high-density electrical method, shallow seismic reflection method and borehole TV comprehensive geophysical exploration have the advantages of multi-physical and multi-scale detection, and can effectively detect the spatial distribution shape, perimeter and sliding zone characteristics of landslides. (3) The results of geophysical exploration and interpretation more reliably reflect the spatial distribution pattern and law of the sliding surface, which can be used as an important basis for guiding drilling layout and landslide stability analysis. (4) The research conclusions are applicable to the investigation of giant deep landslides.
2022 Vol. 39 (8): 6-11 [Abstract] ( 3154 ) HTML (1 KB)  PDF  (972 KB)  ( 1904 )
12 Research on the Comprehensive Railway Line Selection in Mountainous Area of High Pressure Gas and Weak Diagenetic Stratum
NIU Yuancheng
Research purposes: In recent years, attention has been paid on the problem of complex strata during the process of railway construction in Western China. The widely distributed Triassic slate and Neogene sandstone strata greatly increase the difficulty of tunnel construction. In this paper, based on the newly-built tunnel project of Xining to Chengdu railway crossing the Laji Mountain, in view of the complex topographic and geological conditions such as high-pressure gas, weak diagenetic strata and the characteristics of railway construction and operation in mountainous areas, the route selection and engineering problems of long length tunnel in complex strata are studied. Based on the analysis of the geological characteristics and the adaptability of the long tunnel project, and the principles and methods of railway line selection in dangerous mountain area are put forward.
Research conclusions: (1) According to the engineering geological conditions and the similar engineering experience, the route scheme selection principle is determine, the adaptability of different schemes is compared and analyzed from the aspects of the construction difficulty and risk, the auxiliary tunnel setting conditions, tunnel setting and engineering investment. The results show that the tunnelling scheme bypassing the high pressure gas and passing through the shortest in weak rock stratum is optimal. (2) According to the difficulties of engineering construction, the key problems such as tunnel construction, construction scheme, high-pressure gas and tunnel structure design of weak diagenetic strata are studied respectively, and corresponding engineering measures are given. (3) The conclusions of this paper can provide reference for the subsequent similar engineering construction.
2022 Vol. 39 (8): 12-17 [Abstract] ( 3056 ) HTML (0 KB)  PDF  (878 KB)  ( 1913 )
       Main Line: Engineering Geology and Subgrade
18 Strike Slip Fault Failure Mode and Tunnel Engineering Countermeasures
LI Guoliang, HUANG Shuanglin
Research purposes: A 6.9 magnitude earthquake with an intensity of 9 degrees occurred in Menyuan County, Qinghai Province on 8 January 2022, which caused severe damage to the Daliang Tunnel and the Liuhuanggou Bridge of the Lanzhou-Urumqi High Speed Railway. This paper summarizes the earthquake deformation damage through seismic damage investigation and monitoring analysis, and provides an in-depth analysis of deformation laws and seismic damage remediation methods.
Research conclusions: (1) The Menyuan earthquake caused varying degrees of damage to the Daliang Tunnel, with misalignment and twisting of the tunnel near the F5 fracture zone and structural damage, decaying towards both ends of the cavern, with lining cracks, spalling off blocks and circumferential cracks (lines) dominating. (2) The tunnel can be divided into misaligned sections, strongly affected sections and seismic damaged sections according to the degree of damage. In the case of severe damage, the tunnel needs to be dismantled and rebuilt, using the principles of circular section form, laying a damping layer between the initial support and the secondary lining, and setting a 2~3 cm wide deformation joint between sections. (3) According to the relative relationship between the tunnel and the fault, the tunnel is divided into two categories: through active fractures and near active fractures, using different design methods to provide a basis for the design and construction of tunnels near faults. (4) The research results are of significance to the research on the seismic mechanism, seismic design and vibration isolation technology of high intensity earthquake and active fault tunnels in China.
2022 Vol. 39 (8): 18-23 [Abstract] ( 3269 ) HTML (0 KB)  PDF  (1185 KB)  ( 1920 )
24 Intelligent Surrounding Rock Classification Based on Fuzzy Inference
XU Bo, WANG Jiaxin, QIAN Yi, ZHANG Zhongyuan, ZHU Ruoxuan, GE Xiao
Research purposes: The classification of surrounding rock is an indispensable boundary condition in tunnel construction. The traditional method of surrounding rock classification has many drawbacks in terms of timeliness and completeness, and the sample size available in actual engineering is relatively small. In this paper, the fuzzy inference method is introduced to intelligentize the classification of surrounding rock, the fuzzy rules are extracted from the previous classification data of surrounding rock, and a fuzzy inference engine is constructed to realize intelligent classification of surrounding rocks based on fuzzy inference, so as to solve practical problems in engineering.
Research conclusions: (1) Three kinds of fuzzy rule generation algorithms and their advantages and disadvantages are analyzed and studied. (2) The six conditional parameters and value ranges used by the membership function of fuzzy sets are clarified. (3) The feasibility of grading a small number of samples of surrounding rock realizes efficient and accurate grading of surrounding rock. (4) Practice shows that the intelligent surrounding rock classification system designed based on fuzzy reasoning method can meet the actual needs of engineering, and can provide reference for similar engineering applications.
2022 Vol. 39 (8): 24-29 [Abstract] ( 4048 ) HTML (0 KB)  PDF  (672 KB)  ( 1941 )
30 Research on the Three-dimensional Inversion Technology of In-situ Stress in a Long and Deep Tunnel of Haolebaoji-Ji'an Railway
ZHANG Chen, SHEN Bo, LIU Guiwei
Research purposes: Because of the difficulty of regional in-situ stress evaluation and obtaining the real situation of regional in-situ stress through the measured method, based on the measured point in-situ stress data, a method combining GBDT algorithm and three-dimensional numerical simulation is proposed to predict the regional in-situ stress state of rock mass within Ruyi tunnel project scope of Haolebaoji-Ji'an railway. It turns out that the prediction and evaluation of regional in-situ stress level is closer to the actual situation.
Research conclusions: (1) By comparing GBDT algorithm with traditional regression analysis method, the former has higher accuracy, better interpretation and system robustness to low dimensional data which can better map the natural performance of high stress area. (2) The example shows that the combination of GBDT algorithm and numerical simulation method is feasible for regional in-situ stress evaluation. The evaluation conclusion of regional in-situ stress level of Ruyi tunnel project proves that the method proposed in this paper is closer to the actual situation. (3) The numerical inversion results show that the stress value along Ruyi tunnel increases with the increase of buried depth. There is a certain stress concentration at the foot of gully. The horizontal stress field is dominant in this area. (4) The three-dimensional inversion technology of in-situ stress based on GBDT algorithm can be mainly applied to the field of in-situ stress state evaluation of deep buried tunnels.
2022 Vol. 39 (8): 30-34 [Abstract] ( 4019 ) HTML (0 KB)  PDF  (735 KB)  ( 1980 )
35 Failure Mode and Countermeasures of Clay-shale Cutting Slope in Karawang Area, Indonesia
ZHANG Qingbo, WANG Junqiao, ZHOU Bin, HUANG Jianchuan
Research purposes: Clay-shale is a typical expansive sedimentary stratum with poor engineering geological conditions and mechanical properties, and the problem of stability control of cutting slopes is prominent. The Jakarta-Bandung High Speed Railway (JBHSR) crosses the clay-shale stratum located in Karawang area. After 1~2 rainy seasons of cutting excavation, the clay-shale softened in contact with water and quickly disintegrated, causing many cutting slope deformations and damages, which has a significant impact on the project construction. Therefore, it is necessary to carry out research on the failure mode and countermeasures of clay-shale cutting slopes to provide reference for the treatment and protection of clay-shale slopes in this area and similar areas.
Research conclusions: (1) The cutting slope has a clay-shale binary stratum structure, which is marine sedimentary, low in strength and easy to disintegrate. (2) The types of slope failure include shallow slip, layer sliding and collapse, which have the characteristics of bedding, seasonal, gentle, shallow, and polyline shape of the sliding surface. (3) The reduction of shear strength should be considered in the calculation. Take appropriate measures, strengthen drainage, and protect timely while excavation. (4) Measures such as setting up anti-slide piles, supporting seepage ditches, oblique drainage holes, geogrids, and replacement of non-expansive soil can be adopted for landslide treatment. (5) These research results are used for the treatment of clay-shale slope failure on JBHSR, which can accumulate experience in design of this area and similar areas, and provide reference for code revision.
2022 Vol. 39 (8): 35-39 [Abstract] ( 3211 ) HTML (0 KB)  PDF  (1115 KB)  ( 1972 )
       Main Line: Railway and Rail
40 Research on the Release and Control Technology Scheme of CRTS Ⅱ Track Slab
WANG Huiyong, LIANG Yanke, XU Lingyan, KOU Shengyu, XU Peng
Research purposes: To alleviate the expansion of CRTS Ⅱ track slab under high temperature and reduce the expansion-oriented temperature force caused by the restricted deformation of track slab fundamentally, it is necessary to study the stress-relief technology of CRTS Ⅱ track slab in depth. With the analysis of the track-slab structural characteristics in the application scenario of bridge and subgrade, together with the design experience of track slabs in the turnout area, the scheme of continuous track-slab unitization and weak longitudinal connection is proposed. After that, the key parameters are obtained by the analytical method and finite element simulation. Based on the established finite element model, the control scheme after unitization is studied, and the evaluation method together with the allowing superior limit of camber is put forward.
Research conclusions: (1) The stress characteristics of CRTS Ⅱ track slab in subgrade and bridge section are basically the same under high temperature. The critical wavelength of the camber under damage state is determined as 19 m by the analytical method, and the scheme of three-slab unitization is preferred for unlocking. (2) The influence of partial/full filling in wide-narrow joints on the elastic modulus of low-elastic-modulus high-toughness materials is analyzed. It is concluded that the full filling scheme is more favorable to the value-range selection of filling-material elastic modulus. (3) When the track slab is unitized, the uniform planting of reinforcement is more conducive to limit the movement of track plate under high temperature. (4) The method of identifying track camber on the basis of the height variation of rail surface and the height difference variation of rail bottom slab is proposed. It is found the sections where the height variation of rail surface is greater than 2 mm in high-temperature season should be paid more attention.(5) The research result can provide technical support for camber regulation of continuous slab track.
2022 Vol. 39 (8): 40-45 [Abstract] ( 4013 ) HTML (0 KB)  PDF  (909 KB)  ( 1951 )
       Main Line: Tunnel Engineering
46 A Unified Model and Calculation Method of Surrounding Rock Pressure for Shallow Buried Tunnel
XU Chong, WANG Qian
Research purposes: Based on the limit equilibrium principle of wedge body, the horizontal pressure ratio coefficient η and generalized lateral pressure coefficient λ were introduced for getting a unified model and calculation method of shallow buried tunnel during the process of surrounding rock pressure calculation. The model aims to replace the calculation methods of surrounding rock pressure under three different working conditions of ultra-shallow buried, shallow buried ( non-biased ) and shallow buried bias in the Code for Design of Railway ( Highway ) Tunnel using a regular mathematical expression form. The uniformity of the calculation form, the uniformity of the physical essence and the consistency of the calculation steps of the surrounding rock pressure formula of shallow tunnel can be realized, and the theoretical defects of the pressure calculation formula in the industry specification, such as different expression, obscure physical connotation and complicated operation, can be overcome.
Research conclusions: (1) The unified model achieves the unification of the calculation formula of surrounding rock pressure under ultra-shallow buried, shallow buried (non-biased) and shallow buried bias in theory, and the mathematical form is simple. (2) It can be extended to the calculation of tunnel surrounding rock pressure in the form of multi-layer soil, non-horizontal ground with surcharge, irregular sliding wedge, small clear distance and multiple-arch form. (3) The results of unified model are completely consistent with those of Code for Design of Railway (Highway) Tunnel. (4) The unified model and calculation method are of great significance to the revision and supplement of industry specifications.
2022 Vol. 39 (8): 46-52 [Abstract] ( 4013 ) HTML (0 KB)  PDF  (517 KB)  ( 1958 )
53 Definition for Dual-index High Geostress and Classification Standard for Rock Burst and Large Deformation in Railway Tunnels
ZHANG Guangze, JIA Zheqiang, FENG Jun, YUAN Chuanbao, CHAI Chunyang, CHEN Minghao, FENG Tao, TAO Yujing
Research purposes: At present, the classification of large deformation of rock burst in tunnels with high geostress environment is mainly based on theoretical research, and the results are different from the actual construction and excavation. Therefore, by summarizing 78 cases of railway, highway tunnels and hydropower diversion tunnel projects, this paper systematically studies the high geostress state of the tunnel surrounding rock and the classification and definition of the large deformation of rock burst. Combined with the relevant tunnel design specifications adopted in current practical projects, the traditional high geostress identification standard and the rock burst and large deformation classification standard are optimized, and a quantitative definition method that is more in line with the actual engineering is proposed.
Research conclusions: (1) Based on the statistical analysis of engineering cases, a dual-index high geostress quantitative definition method using the strength-stress ratio and the maximum geostress absolute value is proposed, and a dual-index high geostress quantitative identification table for hard rock and soft rock is proposed. (2) A rock burst grade classification standard based on the rock strength-stress ratio R/σmax and the maximum geostress σmax is proposed, and a large deformation grade based on the rock mass strength-stress ratio Rm/σmax and the maximum geostress σmax is proposed. (3) The research results can be applied to the identification of the high geostress state of the surrounding rock of railway tunnels and the classification of disaster grades, and are suitable for the field of engineering geological survey.
2022 Vol. 39 (8): 53-58 [Abstract] ( 3061 ) HTML (0 KB)  PDF  (848 KB)  ( 2080 )
59 Efficiency Coefficient Method for Large Deformation Risk Assessment of Mountain Tunnel
CHEN Xinghai, ZHOU Hang, ZHANG Guangze, ZHAO Xiaoyan, CHEN Minghao, WANG Yandong
Research purposes: Geological conditions of mountain railway tunnels are complex, the tectonic effect is extremely strong, and the rockburst is frequent, which often cause deformation, cracking and even collapse of the supporting structure, etc. It is of great significance to carry out scientific and reasonable risk assessment and take targeted protective measures. Based on the comprehensive analysis of the large deformation failure characteristics and occurrence law, a complete large deformation evaluation index system is constructed. The weight coefficients of each index were comprehensively determined with the combined analytic hierarchy process (AHP) and information entropy weight method (EWM). Based on the theory and calculation rules of the efficiency coefficient method, a large deformation risk assessment model in long tunnel engineering was proposed and applied to of Yangjiaping Tunnel.
Research conclusions: (1) Large deformation is closely related to the maximum principal stress of the surrounding rock cave wall, rock compressive strength, strength-to-stress ratio of surrounding rock, rock elastic modulus, surrounding rock grade, geological structure, and groundwater, and evaluation indexes generally reflect the in-situ stress environment, surrounding rock properties and lithological conditions required for large deformation to occur. (2) Combining the analytic hierarchy process and entropy method, by introducing a distance function, combining subjective weighting and objective weighting to establish a combined weighting rule, this paper solves the problem of the difference between a single objective or subjective weight, and makes the determination of the weight of the large deformation evaluation index more consistent practical and more scientific. (3) The accuracy rate of the evaluation result of the model reaches 90.9%, which verifies the feasibility and accuracy of the model, and it can provide a scientific basis for preventing the occurrence of large tunnel deformation disasters, reducing construction losses and safe operation.
2022 Vol. 39 (8): 59-65 [Abstract] ( 3525 ) HTML (0 KB)  PDF  (645 KB)  ( 1916 )
66 Research on the Disaster Prevention, Evacuation and Rescue Mode and New Type of Emergency Rescue Station in Railway Tunnel with High Altitude
KUANG Liang, HUA Yang, LI Xu, CAO Yu, SU Wei
Research purposes: Considering the influence of high altitude on evacuation capacity and smoke diffusion in trains, the evacuation and rescue mode and new type of emergency rescue station in and out of high-altitude railway tunnel are discussed. At the same time, numerical simulation is used to analyze the law of smoke diffusion in high altitude and large longitudinal slope tunnel, so as to clarify the type and structural design parameters of the new emergency rescue station.
Research conclusions: (1) High-altitude railway tunnels can select two evacuation modes, i.e. evacuation outside the tunnel and evacuation inside the tunnel, based on factors such as climate environment outside the tunnel and safe evacuation time. (2) The external rescue of tunnel can adopt three rescue modes: railway rescue, road rescue and air rescue, the high altitude railway tunnels should adopt the mode of railway rescue. (3) It is recommended to adopt the new emergency rescue station rescue mode consisting of train fire parking area + isolation transition area + rescue train parking area in the high-altitude railway tunnel. (4) Both elevation and slope increase aggravate the spread of smoke in tunnel, and the influence of slope change on the spread rate of fire is more significant than that of altitude change. (5) The research results can guide the design of disaster prevention, evacuation and rescue engineering of high-altitude railway tunnel.
2022 Vol. 39 (8): 66-70 [Abstract] ( 4065 ) HTML (0 KB)  PDF  (771 KB)  ( 1941 )
71 Cause Analysis and Preventive Measures of Blind Drainage Pipe Clogging in Tunnel
CHANG Juyou, LIU Xiang, ZHANG Xinping, YANG Xiangrong, ZHAO Zhong, YANG Wenji
Research purposes: The causes of the blockage of blind drainage pipes in tunnels have not been thoroughly studied, resulting in the seepage and collapse of the weak part of the concrete lining of the second tunnel, which seriously affects the safe operation of trains. Therefore, the reasons for the blockage of blind drainage pipes in tunnels and how to control the blockage of blind drainage pipe in tunnel are studied.
Research conclusions: (1) The blockage of blind drainage pipe of tunnel mainly comes from karst passageway, joint plane and bedding plane of tunnel, and it is the white powder of fine crystal particles in the initial stage when limestone and water produce heavy CaCO3, and it is collected by the hydraulic power of surrounding rock with a large amount. The secondary source is from the tunnel blasting and bolt construction, the fine-grained white powder attached to the cracks and surface of the surrounding rock of the tunnel, and the fine-grained white powder produced from the inside of the shotcrete, which are also collected by the hydraulic power of surrounding rock, and the quantity is less. (2) If the surrounding rock of the tunnel is not limestone and there is fine white powder in the blind drainage pipe, the main source is in the shotcrete. (3) Under the hydraulic action of the surrounding rock of the tunnel, mixing with all the fine white powder to form mixed water, one part of which passes through the surrounding rock to the outlet of the drainage pipe, the other part passes through the permeable layer of shotcrete and collects in the drainage blind pipe. (4) Because of the small diameter of drainage blind eye, the rate of discharging mixed water is reduced, and the white powder is deposited, which causes the drainage blind pipe to discharge unsmoothly and form blockage. (5) The prevention measures include water injection method for blasting hole, high pressure air blast method, special drainage channel, increasing the diameter of blind eye and blind pipe, increasing the outlet of blind pipe, not covering the blind pipe with geotextile, and paying attention to the construction quality of shotcrete. (6) The rate of mixed water discharged from the blind drain to the outlet should be the same as that imported into the front end of the blind drainage pipe. (7) The research results can provide reference for the prevention of blind pipe clogging in the field of railway and highway tunneling.
2022 Vol. 39 (8): 71-74 [Abstract] ( 3355 ) HTML (0 KB)  PDF  (702 KB)  ( 1945 )
       Main Line: Electrification Engineering
75 Research on the Intelligent Traction Substation Area Backup Protection System
SHAO Ming
Research purposes: In order to take full advantage of the characteristics of network data sharing in intelligent traction substation and improve the overall performance of relay protection in traction substation, the disadvantages of traction substation conventional backup protection are analyzed, the functional requirements of backup protection in the station area of traction substation are proposed, the implementation schemes of traction transformer backup protection, bus main and backup protection, feeder remote backup protection, failure protection and dead zone protection based on comprehensive utilization of station area information are discussed, and the backup protection system of traction substation is constructed.
Research conclusions: (1)The traction substation area backup protection system comprehensively utilizes the station information of traction substation, and makes comprehensive judgments based on protection direction selectivity and logic selectivity. (2)The area backup protection system realizes traction transformer backup protection, bus main and backup protection, feeder remote backup protection functions. (3)The analysis of protection action under typical fault conditions shows that the area backup protection system can improve and enhance the performance of traditional backup protection, achieve the goal of fast and accurate removal of faulty components, and improve the reliability of intelligent traction substation backup protection.(4)The research results can provide reference for the optimal configuration of relay protection in intelligent traction substation.
2022 Vol. 39 (8): 75-80 [Abstract] ( 3896 ) HTML (0 KB)  PDF  (440 KB)  ( 1926 )
       Terminal,Station yard and Building
81 Research on the Key Technologies of Application of Exposed Concrete in Xiong'an Railway Station
GU Qiongying, ZHONG Jing, DU Yulin
Research purposes: Xiong'an Railway Station is an elevated type station. Exposed concrete have been applied on all of the main public space. This is the first time that exposed concrete has been massively applied on railway station waiting concourse with concentrated passenger flows and high standard construction. It is not only necessary to solve numbers of problems such as application forms, space effect, equipment and pipeline arrangement, and colour and skin of the envelope, but also need to solve safety and durability problems of structure and architectural aesthetics for Xiong'an Station steel reinforced concrete with huge volume and higher strength.
Research conclusions: (1) By the principle of outstanding professions subject to better system, complete system design is the fundament of exposed concrete application on giant complex architecture. (2) By the principle of integrated thinking of building envelope and skeleton, pithiness and elegant architectural space can be configured by the structure form of curvature concrete beams and columns. (3)The tight coordination between design and construction is an important factor that can guarantee a safe and durable exposed concrete structure, and achieve the expectation of skin and colour effect and beam and column details. (4) Exposed concrete has a wide application prospect in public buildings and large passenger stations.
2022 Vol. 39 (8): 81-86 [Abstract] ( 3896 ) HTML (0 KB)  PDF  (1088 KB)  ( 1933 )
87 Experimental Research on the Joint Seismic Performance of Prefabricated Entrance in the Subway Station
XU Junlin, PAN Zhengyi, XU Junchao, GUO Zhengxing, FANG Cheng, ZHU Zhangfeng
Research purposes: Prefabricated concrete technology has been widely used in underground structures because of its advantages of high production efficiency, easy connection, energy conservation and environmental protection. In view of the poor seismic performance of prefabricated member connections, this paper proposes a fabricated access structure with section steel plug-in connections, and discusses its joint seismic performance. Through the low cycle repeated test, the bearing capacity, energy dissipation capacity, stiffness, failure mode and other indicators of the steel connection joints are obtained and the seismic performance of the steel socket joints is evaluated.
Research conclusions: (1) The test and analysis results show that the failure mode of the specimens is the flexural ductility failure of the side wall as a whole. (2) Compared with cast-in-place specimens, the peak load-bearing capacity, stiffness, ductility and energy consumption of fabricated specimens are basically similar to those of cast-in-place specimens. (3) On the premise that the peak bearing capacity is basically the same, the specimen with a length of 500 mm of section steel has good ductility and energy dissipation performance, and is relatively economical. It is recommended to be used as the preferred scheme for the connection structure of prefabricated access joints.
2022 Vol. 39 (8): 87-92 [Abstract] ( 3739 ) HTML (0 KB)  PDF  (1136 KB)  ( 1908 )
       Urban Railway Development and Technology Research
93 Research on the Inter-connectivity Technology between Suburban Railway and Built Subway
LIU Liefeng, LU Shuai, JIANG Lingchao
Research purposes: The network planning and construction planning of early urban rail transit mainly focused on the internal rail transit and seldom planned the layout of the suburban railways serving the periphery of the city in advance. Most of the important corridors are occupied by urban rail transit, and it is extremely difficult to select the line for suburban railway through the central city. The demand for direct passenger flow to the central city cannot be effectively alleviated. It is of great significance to study the inter-connectivity technology between suburban railway and built subway in order to reduce transfer times, make full use of existing corridor, attract passenger, reduce investment and improve service quality.
Research conclusions: (1) Combined with the technical standards of the existing subway, it is recommended to adopt dual-current system vehicles for inter-connection between urban railway and subway. (2) The structure gauge should meet the requirement of dual-current vehicles passing. (3) AC 25 kV and DC 1 500 V power supply modes are adopted. (4) A transition neutral section or system separation section is set between different power supply systems. (5) If the existing signal system is not inter-connected, products should be used from the same manufacturer to meet compatibility requirements. (6) Overhead catenary is generally adopted in dual-current system, and the overhead catenary in transition section should be adopted in the form of neutral insulated anchor joint. (7) These turn-back stations of the existing subway line should meet early, near-term, forward operating-diagram. (8)Through analyzing the problems of inter-connection in the vehicles, power supply and transformation, communication signals and civil sidings, the solutions are put forward to break through the technical obstacles of inter-connection between suburban railway and built subway, and provide technical support for the operation of cross-line trains.
2022 Vol. 39 (8): 93-97 [Abstract] ( 3996 ) HTML (0 KB)  PDF  (484 KB)  ( 1928 )
98 Experimental Study on Design of Near Rail Noise Barrier for Wenzhou Surburban Railway
DING Yachao
Research purposes: Our country encourages surburban railways to adopt elevated or ground laying system, which need low noise elevated rail transit technology to provide environmental protection support. Through this research, a new method to reduce railway noise in surburban railways is found.
Research conclusions: (1) It is the first time in China to adopt the method of combining design research and engineering test for the near rail noise barrier of Wenzhou S1 line. Based on the analysis of noise sources, considering load, clearance, connection with existing bridge deck system, acoustic performance of sound barrier unit plate, structural safety and other factors, the combination design of near rail sound barrier and track bed is proposed. (2) The effect is verified by engineering test, the noise source intensity of the train 25 m away from the track center line and 3.5 m above the track surface is reduced from 80 dB to 66 dB, the insertion loss of near orbit noise barrier is 11～13 dB, the project cost is saved by 21%～46% compared with the traditional noise barrier. (3) The noise reduction effect of near rail noise barrier technology is good, the investment is low, the construction is simple, safe and reliable, the landscape is good, and it can provide reference for the vibration and noise reduction scheme of surburban railway.
2022 Vol. 39 (8): 98-104 [Abstract] ( 3382 ) HTML (0 KB)  PDF  (987 KB)  ( 1922 )
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