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2014 Vol. 31, No. 11
Published: 2014-11-15
Geology and Subgrade
Railway and Rail
Bridge Engineering
Tunnel Engineering
Electrification Engrinnering
 
       Geology and Subgrade
1 Design Research on the Subgrade Structure of Heavy Haul Railway Hot!
GUO Kang-mei, WANG Yan, YE Qing-zhi, LIU Jing-lei
Research purposes:Nowadays the design of subgrade thickness of heavy haul railway in China bases on current specification for subgrade design of high speed railway, but work mechanism of the subgrade under the load of heavy haul train and high speed train differs widely from each other. For this purpose, according to elastic theory, track-subgrade three-dimensional finite element model is established in this paper, thus to analyze the dynamic stress distribution and attenuation law of the subgrade at different load levels and in different structural styles. In addition, the design method of dynamic strength control is suggested to confirm the thickness of the subgrade bed of the heavy haul railway under different loads.
Research conclusions:(1) The decay rate of dynamic stress reduces significantly under the load of heavy haul railways on account of the fact that the superimposed effect of shaft should be taken into account. (2) According to the current design method of heavy haul railway, the ratio between dynamic stress and self-weight stress on the design thickness of the subgrade under superimposed load is calculated out to be 0.3~0.5, which does not meet the design requirements. (3) By adopting the dynamic strength design principle, the entire thickness of the subgrade bed should be 2.1~2.3 m under the axle load of 25 tons, 2.8~2.9 m under the axle load of 30 tons, 3.2~3.3 m under the axle load of 35 tons. (4)The conclusions above provide valuable reference for heavy haul railway subgrade bed structure design.
2014 Vol. 31 (11): 1-5 [Abstract] ( 5069 ) HTML (1 KB)  PDF  (809 KB)  ( 467 )
6 Design Research of Cantilever Retaining Wall Based on Limit State Design Method Hot!
WEI Yong-xing, LUO Yi-nong, LIU Chang-qing
Research purposes:The cantilever retaining wall is a common retaining structure used at home and abroad. The research on cantilever retaining wall limit state design is to examine the safety of the wall type designed according to current specification and give the limit state design expression to the external stability for calculation. This paper has summed up the research thought of cantilever retaining wall and analyzed the main calculation results, which provides a reference for standard revision and the further study of the earth pressure.
Research conclusions:(1) The research steps of cantilever retaining wall limit state design are to establish a limit state equation, calculate reliability index and determine the target reliability index, calculate partial coefficient and set up the design expression. (2) The reliability index analysis of cantilever retaining wall such as anti-sliding, anti-capsizing and stress of the basement and strength of components showed that the intensity of cantilever retaining wall can achieve integral sliding resistance and component crack control design. (3) The motion resistance calculation of cantilever retaining wall can be designed according to the design expression recommended in this paper. (4) For the structure design of cantilever plate of cantilever retaining wall, partial coefficient should be adjusted according to the earth pressure calculation. (5) The research conclusion can be used for reference in the design of cantilever retaining wall.
2014 Vol. 31 (11): 6-9 [Abstract] ( 5087 ) HTML (1 KB)  PDF  (386 KB)  ( 166 )
10 Design Research of Pile Plate Retaining Wall Based on Limit State Design Method
LUO Yi-nong , LIU Chang-qing , WEI Yong-xing
Research purposes:The pile plate retaining wall is a common retaining structure. The research on pile plate retaining wall limit state design is to examine the safety of the structure designed according to the current design specification, and give design expression of anchorage segment limit state. This paper has summed up the research thought of pile plate retaining wall and analyzed the main calculation results, which provides a reference for pile plate retaining wall limit state design.
Research conclusions:(1) The research steps of the pile plate retaining wall limit state design are to establish a limit state equation, calculate reliability index and determine the target reliability index, calculate partial coefficient and set up the design expression. (2) The reliability index analysis of shoulder type pile plate retaining wall showed that the reliability index meet or close to the demand of the public. (3) The pile plate retaining wall can be designed with reference to the current code for design of railway retaining structures of railway subgrade, but for the design of the high slope embankment and cutting wall, the partial coefficient of larger loads should be adopted, at the same time in the design attention should be paid to the measures to reduce the earth pressure of slope. (4) The design expression for calculating the shoulder type pile plate retaining wall anchoring segment and recommended values of partial coefficient are proposed. (5) The research conclusion can be used for reference in design of the shoulder type pile plate retaining wall.
2014 Vol. 31 (11): 10-14 [Abstract] ( 4874 ) HTML (1 KB)  PDF  (416 KB)  ( 95 )
15 Design Research of Anchor Rod Retaining Wall Structure Based on Limit State Design Method
LIU Chang-qing, LUO Yi-nong , WEI Yong-xing
Research purposes:The anchor rod retaining wall is widely used in high slope engineering. The research of anchor rod retaining wall limit state design is to examine the safety of the structure in the current design specification, and give design expression to anchorage segment limit state.
Research conclusions:(1) The research steps of anchor rod retaining wall structure limit state design are to establish a limit state equation, calculate reliability index and determine the target reliability index, calculate partial coefficient and set up the design expression. (2) For the anchor rod retaining wall structure reliability index, most of recommended values can satisfy the public demand, but when the slope is higher, the reliability index is low. (3) The anchor rod retaining wall can be designed with reference to the current Code for Design of Railway Retaining Structures of Railway Subgrade, when the slope is higher, it is suggested that the partial coefficient of load is appropriately increased, and attention is paid to the design of slope form and slope surface reinforcement. (4) The research conclusion can be used for reference in the design of anchor rod retaining structure.
2014 Vol. 31 (11): 15-19 [Abstract] ( 4939 ) HTML (1 KB)  PDF  (412 KB)  ( 135 )
20 Detection Test and Condition Assessment on Existing Heavy Hual Railway Subgrade
NIE Ru-song, LENG Wu-ming, YANG Qi
Research purposes:Field tests including the degree of compaction K, water content, direct shear test, N10, K30, the strain modulus Ev2 and dynamic deformation modulus Evd were performed on four typical subgrade diseases worksite of Shenchi-Huanghua Heavy Haul Railway, the compaction performance, deformation behavior and bearing capacity of the subgrade were systematically assessed. For the feasibility and representative of subgrade test of existing railway, ignore the influence of the new rolling residual stress and train load repeated function, a plane strain finite element model was set up to analyze the initial state of subgrade which can give reference for determining the field testing points and confining pressure of dynamic triaxial tests in lab.
Research conclusions:(1) The compaction performance, the deformation behavior and bearing capacity of the four subgrade worksite with diseases fail to meet the requirements of Chinese codes, which need to be reinforced. (2) The initial state of subgrade is very complicated. If the residual stress induced by rolling and train load is neglected, the soil mass 5.5~6.0 m away from the centre of subgrade and 0.6~1.2 m depth from subgrade surface is in K0 condition. (3) When the dynamic triaxial tests in lab for subgrade fillings are performed, the determination of load parameters should take the initial state of subgrade into account. (4)The results are helpful for detection test and condition assessment of railway subgrade.
2014 Vol. 31 (11): 20-24 [Abstract] ( 4786 ) HTML (1 KB)  PDF  (508 KB)  ( 180 )
25 Research on the Correction Method of the Spacing of Acoustic Detecting Pipes in Pile Detection
ZHAO Chang-yao, YANG Dong-tao
Research purposes:Because pile is a concealed engineering, the pipe spacing between measuring points is defaults to edge distance between acoustic detection pipes of pile top surface. So acoustic detecting pipes layout should be parallel to each other. When acoustic detecting pipe layout is not parallel to each other, the spacing between measuring points is not corresponding with the edge distance of pile top surface. Under the circumstances the edge distance of the pile top surface is defaulted instead of the spacing between measuring points which influence the data analysis of pile quality judgement. So correction method must be employed to correct the pipe spacing between measuring points, to bring the pipe spacing return to the site of the real or close to the real pipe spacing, thus to further judge the quality of pile.
Research conclusions:(1) Establish the mathematical model about the spacing position relations of acoustic detecting pipe, deduce the correction method and compile the corrective procedure.(2) When the acoustic detecting pipes are parallel to each other, the revised spacing has no obvious change, which shows that this correction method will not bring external interrupt on normal section of acoustic detection pipe. (3) After abnormal section space of acoustic detecting pipes is modified, the pipe spacing and sound velocity value of measuring points can return to the corresponding real value.(4) The correction method has the very good practical value in pile engineering quality detection.
2014 Vol. 31 (11): 25-29 [Abstract] ( 4842 ) HTML (1 KB)  PDF  (1772 KB)  ( 76 )
       Railway and Rail
30 Design and Optimization of High-speed Railway Lines Based on Comfort
WANG Hai-yong, DANG Jian-wu, WANG Xiao-ming
Research purposes:To enhance the passengers ride comfort on the high-speed trains, the design and optimization of high-speed railway lines should be paid much attention to as well as speed up improving performance of high-speed trains. Therefore, the relationship between the comfort and line parameters of high-speed railway has been systematically analyzed and researched.
Research conclusions:(1) The evaluation model of comfort based on line parameters has been established and the corresponding evaluation interval has been determined. (2) According to code for design of high speed railway (trail), during line parameter design, not only the practical landform and working conditions should be considered, but also the ride comfort ought to meet the needs of passengers. Thus, a relatively reasonable line can be designed by choosing plane and vertical curve parameters. (3) After the analysis of the design and optimization of plane curve radius based on the comfort of passengers, the recommended minimum of plane curve radius under different running speed can be obtained. (4) The research results can provide better guidance for the design and optimization of high-speed railway lines in future.
2014 Vol. 31 (11): 30-34 [Abstract] ( 4829 ) HTML (1 KB)  PDF  (600 KB)  ( 117 )
35 Type Selection of Track Structure on New Baishatuo Yangtze River Bridge of Chongqing-Guiyang Railway Hot!
WANG Ming-hui, LI Kai-lan
Research purposes:Whether the reasonable track structure is adopted or not on large span steel bridge affects directly the normal running of train because a large vertical displacement and greater natural vibration frequency under loads. This paper introduced main track structure types at home and abroad, took new Baishatuo Yangtze River Bridge of Chongqing-Guiyang Railway for example, systematically analyzed the adaptability of track structure and steel bridge, determined reasonable track structure of the bridge.
Research conclusions:(1)The ballasted track structure can better adapt the deformation of steel bridge and deformation caused by the track dead load on New Baishatuo Yangtze River Bridge of Chongqing-Guiyang Railway.(2)The track ballast bed and the mechanical characteristics of the bridge axle vibration is clear, which can also better adapt the characteristics of high natural vibration frequency of the steel bridge.(3)Ease of construction and maintenance comes from the mature and stable technology of the ballasted track structure.(4)The results in this paper has a certain reference value on the selection of track structure on large span or heavy haul steel bridge.
2014 Vol. 31 (11): 35-37 [Abstract] ( 4821 ) HTML (1 KB)  PDF  (404 KB)  ( 35 )
38 Reasonable Style and Mechanical Property of Ballastless Track on Soil Subgrade
YANG Jian, WANG Jin-sheng, PENG Xin
Research purposes:Considering the characteristics of the ballastless track on soil subgrade, the finite element analytical model of slab ballastless track on soil subgrade was established to study the reasonable track structue and to analyze the effects of base dimensions on the mechanical property of slab track structure on soil subgrade, for purpose of providing references in the application and design of ballastless track structue on soil subgrade.
Research conclusions:(1) Compared with the solid slab, frame slab can effectively reduce the stress and displacement of the track slab under the action of load, the maximum stress and displacement of frame slab decreased about 16% and 11% respectively, meanwhile, the dead load of the frame slab decreased about 30%, and laying the frame slab on soil subgrade has a high level of techno-economic advantages. (2) The mechanical property of frame slab ballastless track is influenced more by the thickness of base than by the width. (3) The change of the base dimension won't affect the stress distribution rules of the frame slab. (4) The reasonable recommended values of the width of roadbed on soil subgrade is about 300~320 cm and the thickness is about 30 cm. It's not necessary to increase the size of base for the purpose of reducing the stresses of the structure. (5) The research results can provide theoretical basis for the design and maintenance of ballastless track.
2014 Vol. 31 (11): 38-43 [Abstract] ( 4784 ) HTML (1 KB)  PDF  (1097 KB)  ( 28 )
44 Research on the Crack Repairing Materials of CA Mortar of CRTS I Ballastless Track
ZHANG Jian-hua,YANG Yan,LIU Shang-chun, SUN Kun
Research purposes:This paper analysed the causes of crack of CA mortar of the high-speed railway of CRTS I slab ballastless track. The basic technical requirements of the crack repairing was proposed, the performances of the epoxy resins and the high performance modified resins were compared and studied, such as the construction feasibility, the fill adaptability and the durability. Through the contradistinctive experimental research, the new material of crack repairing of CA mortar was got, which had more construction feasibility, fill adaptability and durability.
Research conclusions:(1)Through the comparative analysis, it shows the construction and filling adaptability, RX-SI is suitable for the actual CRTS I CA mortar from the joint construction process. The construction process is simple and feasible.(2)The durability research results show that the elastic modulus, elastic modulus and CA mortar RX-SI perfectly matched, RX-SI can ensure the ballastless track plate repair processing structure safety and durability. (3) The results of the research are specially designed for CRTS I ballastless track CA mortar joints, which can be well widely used in the CRTS I ballastless track CA mortar gap repair.
2014 Vol. 31 (11): 44-49 [Abstract] ( 4830 ) HTML (1 KB)  PDF  (1458 KB)  ( 100 )
50 Experimental Research on the 75N Rail Hot!
LIU Feng-shou, ZHOU Qing-yue, ZHANG Peng-pai, ZHANG Yin-hua, CHEN Zhao-yang, LI Chuang, YU Zhe, LIANG Xu
Research purposes:75 kg/m rail with new profile (75N rail) is designed for adverse match the wheel-rail of the early stages of rail use in Datong-Qinhuangdao railway heavy line. The contact state and the geometry relation are compared and analyzed by simulation before and after optimization of 75 kg/m rail, 75N rail is tested in Datong-Qinhuangdao railway heavy line.
Research conclusions:(1) 75N rail can significantly improve the wheel-rail relationship,The wheel- rail contact position is in rail head tread center area, The wheel-rail contact stress decreases sharply; (2) Regardless of pre-grinding or not pre-grinding, the wheel- rail contact position is centered in a straight line. Gauge corner does not appear the crushing and shelling, Application of The new profile of 75N rail is in good condition; (3) When 75N rail is used in curve, gauge corner does not appear the crushing, it shows good relationship of wheel-rail contact. (4)This research results can be used in rail of heavy haul railway.
2014 Vol. 31 (11): 50-53 [Abstract] ( 4792 ) HTML (1 KB)  PDF  (989 KB)  ( 49 )
       Bridge Engineering
54 Shear Lag Analysis of Simply Supported Box Girders under Prestressing Effect
LIN Peng-zhen, LIU Ying-long,SUN Li-xiang, YANG Zi-jiang, JI Wei
Research purposes:In order to calculate the shear lag effect of box girders due to prestressing, analytical solutions of shear lag effect of simple supported box girders due to straight, harped and draped prestressing tendons are presented based on energy variational principle and equivalent load method. Taking a simple supported box girder as an example, shear lag effect under three tendons arrangements are calculated and compared with numerical solution which using shell finite element method. For 10 typical standard box girders on high-speed railway bridges, shear lag coefficient at the point of maximum stress are calculated.
Research conclusions:The results show the following conclusions:(1) Compared with solution of finite element method, the analytical solutions can effectively calculate the shear lag effect of simply supported beams due to the prestressing action. (2) For typical standard box girders on high-speed railway bridges, the straight tendons arrangement can cause the minimum shear lag effect, followed by draped tendons, harped tendons are the maximum. (3) The research results have theoretical references for the design of prestressed concrete box girders.
2014 Vol. 31 (11): 54-58 [Abstract] ( 4779 ) HTML (1 KB)  PDF  (466 KB)  ( 77 )
59 Research on the Adaptability of High Pier Railway Bridge
CHEN Si-xiao, WU Zai-xin,ZHONG Ya-wei
Research purposes:For the railway across dangerous mountainous area where there are deep canyons, a large number of long-span and high pier bridge is necessary. With the increase of running speed of newly-built railway and height of pier, in order to meet the dynamic performance of bridges, the selection of different types of high pier according to engineering geological characteristics of mountainous terrain is more important to reduce work quantities of pier and to optimize its economic indicator. In this paper, a study is made on the adaptability of high pier for railway bridge to master the mechanical characteristics, application range of rational height and economic indicator of different types of high piers.
Research conclusions:(1) This paper puts forward the economical and reasonable application scope of different high pier types: when H ≤80 m, single slope hollow pier should be the first choice; when 100 m>H> 80 m, the broom-type pier is more economical; when H>100 m, A- type (including herringbone) pier has obvious economic advantage; herringbone pier is suitable for high pier bridge with a height of 100~ 120 m, when H>120 m, A-type high pier should be the preferred choice. (2) Choice of reasonable foundation type for A-type (including herringbone) pier under different geological conditions in the mountainous areas: for the location where topographical slope is relatively steep and geologic condition is relatively good, A-type slant-legged separated foundation with unequal height may be used; for the location where the topographical slope is relatively gentle and the geological condition is relatively poor, A-type pier dumbbell foundation or monolithic foundation may be used. (3) The research achievement in this paper has a guiding significance to rational selection of pier type of railway bridge in the dangerous mountainous area.
2014 Vol. 31 (11): 59-64 [Abstract] ( 4823 ) HTML (1 KB)  PDF  (1114 KB)  ( 45 )
65 Evaluation of Seismic Vulnerability of Reinforced Concrete Circular Hollow High-piers Hot!
ZHOU Chang-dong, CHEN Jing, ZENG Xu-lang, LIU Bin
Research purposes:Cross-section form has a great impact on the mechanical properties of the pier of railway bridges, and hollow concrete high-piers show obvious superiority. However, the research of the seismic behavior for reinforced concrete (RC) circular hollow high-pier needs to be further carried out. The curvatures of the control section of the circular hollow high-pier corresponding to the material damage are chosen as a damage status. This paper presents seismic response of RC circular hollow high-pier under 15 earthquake ground motion records using incremental dynamic analysis, proposes the probability of expected damage modes forms the vulnerability curves, studies the seismic performance of circular concrete high-piers.
Research conclusions:The following conclusions can be got from the above analysis: (1) The damage area of RC circular hollow high-pier appears not only at the bottom of the pier but also in the middle of the pier and on the top of the pier under the earthquake, but the vulnerability at the bottom of the pier is higher than that of other areas; (2)The probability of the complete injury is small, and it indicates that the seismic performance of the RC circular hollow high-pier is good; (3) The seismic vulnerability analysis of circular hollow high pier provide theoretical basis for seismic performance research of the practical engineering.
2014 Vol. 31 (11): 65-71 [Abstract] ( 4845 ) HTML (1 KB)  PDF  (1675 KB)  ( 177 )
72 Research on the Checking Indexes of Concrete Gravity Type Piers with Low Longitudinal Reinforcement Ratio under a Low-level Earthquake
ZHANG Yong-liang,CHEN Xing-chong,DING Ming-bo, PEI Lu
Research purposes:Concrete gravity type piers with low longitudinal reinforcement ratio are extensively used in high-speed railway in China. However, how to check such structures is not specified in current technical codes. With the round end pier of 32 m simply-supported girder bridge as research subject, how to check the structures by eccentricity and stress indexes is studied. The effect of longitudinal reinforcement on improving the bearing capacity and stability of the pier is discussed.
Research conclusions:(1) The allowable stress approach or section eccentricity could be used to check concrete gravity type piers with low longitudinal reinforcement ratio. Strength and stability of the pier can be ensured when the allowable stress approach is used. (2) When section eccentricity is used as checking index, the restriction values may vary from longitudinal reinforcement ratio. (3) For the round end piers with longitudinal reinforcement ratio of 0.1%, 0.2%, 0.3% and 0.4%, permissible eccentricity can be magnified to corresponding values for 0.90S, 1.0S, 1.1S, 1.2S. (4) The results can provide a theoretical basis for calculation method of the concrete gravity type pier with low longitudinal reinforcement ratio under low-level earthquakes.
2014 Vol. 31 (11): 72-76 [Abstract] ( 4800 ) HTML (1 KB)  PDF  (1062 KB)  ( 51 )
77 Dynamic Characteristic Analysis of Girder Hoisting Machine Structure Based on Linear Stiffness Ratio Hot!
CHEN Shi-tong, SUN Zhi-xing, LI Xiang-dong, WANG Hai-lin
Research purposes:Large-tonnage girder hoisting machine often need to be transformed to meet the engineering environment. The dynamic characteristic change is easily ignored in the conventional transformation, resulting in unnecessary engineering accident. Therefore, based on the linear stiffness ratio of girder hoisting machine leg and main girder line, the influence law of the leg height on dynamic characteristics was systematically analyzed so as to offer the reference for transform and design of the girder hoisting machine.
Research conclusions:(1) The longitudinal and lateral dynamic characteristics are sensitive to the change of linear stiffness ratio of girder hoisting machine leg and main girder line, the change of the linear stiffness ratio will cause the significant changes of the vibration frequency and vibration model. (2) The vertical dynamic characteristics are not sensitive to the change of linear stiffness ratio, but are sensitive to the change of vertical load. (3) To ensure the operation safety of the girder hoisting machine, the dynamic coefficient of lifting must be researched in the process of the transformation. (4) According to the practical engineering for analysis, the research results is suitable for the girder hoisting machine transformation and new equipment design and development.
2014 Vol. 31 (11): 77-81 [Abstract] ( 4792 ) HTML (1 KB)  PDF  (1334 KB)  ( 45 )
       Tunnel Engineering
82 Research on the Numerical Simulation Method of Grouting in Tunnel Hot!
GAO Feng, TAN Xu-kai
Research purposes:For improving the accuracy and calculating precision of simulation method for the reinforcing measure in tunnel construction, the calculation error caused by routine method was studied. The reason for the calculation error was analyzed by finite element theory. And then two improved methods were brought up.
Research conclusions:(1) For the nodal displacement or strain in last load step, improving element′s parameters directly in reinforcing area makes nodes′ internal load increasing in the load step, which will arouse false results. (2) Two improved methods are taken to simulate the reinforcing measure. The one is that a layer of elements are adhered to each element in the reinforcing area to simulate the reinforcement, the another is that improving surrounding rocks parameters after relieving the strains field and retaining the stress field of last step. (3)The improved methods to simulate the reinforcing measure are verified by model test. (4)The improved methods in this paper can improve the calculating precision for the reinforcing measure simulation in tunnel engineering and geotechnical engineering.
2014 Vol. 31 (11): 82-86 [Abstract] ( 4774 ) HTML (1 KB)  PDF  (527 KB)  ( 84 )
87 Study and Application of Safety Grade of Surrounding Rock Deformation in Construction of Railway Tunnel
ZHANG Min-qing,HUANG Hong-jian,WU Chuan
Research purposes:There are more than 4000 railway tunnels under construction which are about 8 000 km in China.In recent years the tunnel collapse accident occasionally occurred, causing casualties, economic losses and social influence of certain. Establishing the safety grade of railway tunnel surrounding rock deformation is very important for site management. On the basis of research results at home and abroad, this paper analyzed safety monitoring data, which is supplemented by theoretical calculation and based on the safety of initial support, formulated the railway tunnel deformation control safety management numerical value.
Research conclusions:(1) The current safety grade management of railway tunnel surrounding rock deformation can not integrate with the international standards. (2) By using standard design parameters and numerical simulation computation, vault settlement after excavation supporting of surrounding rock grade Ⅳ tunnel is 11 mm, the surrounding rock grade V tunnel is 19 mm, and field measurement is far larger than the value. Therefore, the deformation of tunnel surrounding rock is mainly controlled by the excavation method, the initial supporting construction quality, and the initial support closed timeliness. (3) The management of early warning level 2 and warning level 1 is carried out according to the total deformation and deformation rate of tunnel surrounding rock deformation, total deformations of grade Ⅲ are 40 mm and 80 mm respectively, grade IV are 50 mm and 100mm,grade V and VI are 75 mm and 150 mm, deformation rate are 5 mm/d and 10 mm/d. (4) The research results can be used for railway tunnel surrounding rock deformation monitoring and safety management.
2014 Vol. 31 (11): 87-93 [Abstract] ( 4938 ) HTML (1 KB)  PDF  (503 KB)  ( 78 )
       Electrification Engrinnering
94 The Application Prospect of Amorphous Alloy Core Transformer in Railway Power Supply Systems
MA Feng-chao, NIU Da-peng, HAN Cheng
Research purposes:With the rapid increase of power load application requirements of communication base station, repeater station, disaster prevention, signal relay station, auxiliary power of traction substation, switching station and other interzone, the number of 10/0.4 kV transformer is increasing consequently for those power loads, which aggrandizes the wastage of the transformer. For the purpose of reducing the wastage of existing transformers, this paper compares the annual power loss of amorphous alloy transformer with S11 transformer, calculates and contrasts TOC value of the two type transformer with comprehensive cost of energy efficiency method, which illustrates the energy conservation value of the amorphous alloy transformer.
Research conclusions:(1) The no-load loss of amorphous alloy transformer is about 75% lower than S11 transformer, and the annual power loss of amorphous alloy transformer is about 30% less than S11 transformer; (2) The TOC value of amorphous alloy transformer is at least 20% less than S11 transformer; (3) With the increase of capacity, the TOC value difference between amorphous alloy transformer and S11 transformer is also increasing. (4) The amorphous alloy core transformer can be widely used in pole-mounted transformer, prefabricated substation,and indoor substation for railway power supply systems.
2014 Vol. 31 (11): 94-97 [Abstract] ( 4764 ) HTML (1 KB)  PDF  (343 KB)  ( 95 )
98 Research on the Construction Control and Numerical Simulation of the Existing Civil Air-defence Tunnel Reconstruction
LIU Ming-hui,YIN Ai-guo, GUO Wei
Research purposes:The existing civil air defense tunnel reconstruction gets few examples in China. This paper relies on monitoring measurement technology and the theory of finite element analysis, studies the displacement, deformation, and stress characteristics on different stages of dynamic tunneling during the single and bilateral excavation. We improved construction plan, strengthened the construction process control, and compared the numerical simulation results with site measures to ensure the safety of tunnel reconstruction.
Research conclusions:(1) The main parameters such as the maximum ground settlement caused by unilateral and bilateral excavation and the stress of surrounding rock meet the code and design requirements. This shows that the construction scheme is reasonable. (2) The rock structure experiences a trend of decreasing tensile stress and increasing compressive stress with the excavation. The maximum tensile stress of the rock structure drops dramatically as the initial support and temporary support. The maximum compressive stress increases dramatically when the top structure is excavated. (3) A two-meter single side excavation of the existing structure is followed by a ground surface sedimentation of 15.10 mm while a one-meter bilateral excavation expects a ground surface sedimentation of 23.67 mm, which is very close to the designed warning value (24 mm) and shall be strictly controlled during the construction. (4) This paper presents the construction methods and measures such as temporary vertical advance reinforcement, side wall and invert, radial grouting, supported by pipe shed, excavation and so on, which can make the internal force change under control, control the displacement of vault, the inverted arch and surface effectively, and ensure the safe of structure and construction. (5) This paper summarizes the deformation rules of surrounding rock, surface, liner structure and so on, which can provide references for the design and construction of similar projects.
2014 Vol. 31 (11): 98-103 [Abstract] ( 4813 ) HTML (1 KB)  PDF  (1078 KB)  ( 358 )
104 Visual Monitoring Technology for Structure Stress of Metro Shield Tunnel
HE Chun, ZHANG Kao, ZHOU Cheng
Research purposes:As the subway tunnel is an important infrastructure in the city, safety monitoring during construction will become necessary. In view of the shortcomings of the current segment monitoring, such as security flaws, inefficient judgment lag in data analysis and visualization to synchronization, in this paper we have adopted a set of visual monitoring device, which takes advantage of the vibrating wire sensor technology, to monitor the safety of the lining process during the construction of Wuhan Metro Line Four phase two project of the tunnel, and monitoring includes the steel bar stress of the segment and the strain of concrete in the segment. Using ARIMA modeling to analyze the monitoring results, we have verified the reliability of the visual monitoring device to obtain data.
Research conclusions:The visual monitoring device we adopted in the project, which is combined with the vibrating wire sensor technology, has so many advantages, such as high frequency data acquisition, real-time visual surveillance, stable data acquisition and so on. Through ARIMA model analysis of the monitoring data in August, 2013, we have obtained the following conclusions:(1)The time sequence of strain of concrete and the steel bar stress showed a tendency generally, meanwhile there exists fluctuation partially, it is a non-stationary time sequence. (2)The time sequence changes slowly, the monthly change of concrete strain is in the range of 16~20 με, reinforcement stress amplitude is at about 1 kN. (3)After the first order difference, the nonstationary time sequence turns to be stable. (4) The concrete strain time sequence shows the partial correlation significantly, and the reinforcement stress time sequence presents self-correlation as well as partial correlation. (5) The visual monitoring technology mentioned in this paper can monitor structure stress of metro shield tunnel in the complicated environment.
2014 Vol. 31 (11): 104-110 [Abstract] ( 4913 ) HTML (1 KB)  PDF  (696 KB)  ( 105 )
111 The Application of LTE in Wireless Transmission of Subway Passenger Information System
HUANG Jia-qiang
Research purposes:With the rapid development of urban rail transit construction in our country, the passenger demand for information system also is increasing day by day, the deep industrial upgrading of the rail transit industry is driving industry wireless private network to broadband networks, which need to support real-time mobile broadband access under the condition of high-speed. With the characteristics of wide range, high bandwidth, a number of concurrent users, strong anti-jamming capability, safe and reliable, LTE is becoming the choice of wireless private network of rail transit industry to develop new technologies. Through the analysis and study of the application of LTE in wireless transmission of subway passenger information system, this paper can provide the reference for the similar problems in the subway design and construction.
Research conclusions:Through the study, it is concluded that: (1) Suggest that the wireless network subsystem of the subway passenger information system is made of TD-LTE technology, the frequency of use is 1 795~1 805 MHZ. System is made of switching equipment setting up in the control center, baseband equipment (BBU) setting up at the station, remote device (RRU) and road equipment setting up in the interval, car wireless devices and transmitting antenna and optical cable laying in interval tunnel, etc. (2) The long distance underground tunnel is recommended to use RRU cascade to extend coverage. Suggest system adopt community merging method, reduce the number of community, and reduce the number of switch. (3) The proposed system solutions offer the reference for the future wireless network design in urban rail transit.
2014 Vol. 31 (11): 111-120 [Abstract] ( 4826 ) HTML (1 KB)  PDF  (589 KB)  ( 104 )
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