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Analysis of temperature characteristics of high-speed train wheelset system under co.plex operating co.ditions

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International Journal of Mechanical System Dynamics 2024年第3期4卷 331-345页

作者： Baosen Wang Yongqiang Liu Yingying Liao Yixuan Wang School of Mechanical Engineering Shijiazhuang Tiedao UniversityShijiazhuangChina Hebei Key Laboratory of Mechanical Power and Transmission co.trol Shijiazhuang Tiedao UniversityShijiazhuangChina School of Civil Engineering Shijiazhuang Tiedao UniversityShijiazhuangChina Taiyuan Vehicle Depot Daqin Railway Co.Ltd.TaiyuanChina

With the rapid advancements in high-speed train technology,the importance of ensuring the safety of train operations has beco.e ***,being a critical co.ponent of train bogies,have garnered significant attention for their role in maintaining safety *** the temperature of bearings to evaluate their motion state is a co.mon practice in high-speed trains,emphasizing the need for further research into temperature *** this study,a dynamic model is developed for the bearing rotor system of high-speed *** co.sidering the co.tact points between raceways and rolling elements,the power loss in the bearing is obtained and a transient temperature-field model of the system is *** relationship between node temperature and factors such as ambient temperature,train running speed,and load is illustrated,with a detailed presentation of the influence of bearing fault type and size on node *** analysis results reveal that the node temperature increases with higher values co.responding to those quantifiable factors and is most affected by rolling element ***,it is observed that the temperature rises rapidly in the initial stage and gradually flattens out over *** co.parative analysis of temperature under different fault co.ditions shows that the node temperature is most affected by the rolling element *** and actual line temperature data are used to verify the validity of the *** co.parison results show that the simulation aligns well with experimental and line *** transient temperature-field model of the bearing rotor system in high-speed trains can effectively simulate and predict the temperature change process of each node of the *** simulation results hold certain theoretical guiding significance for further research and practical applications in ensuring train operation safety.

关键词： high-speed train dynamic model transient temperature field bearing fault line data

co.struction technology for deep tunnels crossing superhigh-temperature fault zones with high water surges

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Frontiers of Structural and Civil Engineering 2024年第8期18卷 1267-1280页

作者： Yong ZHAO Tingyu ZHU Li YU Ming LU Sichuan–Xizang railway co. Ltd.Linzhi 860000China School of Civil Engineering Southwest Jiaotong UniversityChengdu 610036China

The harsh environment in tunnels with high geothermal temperatures and humidity can adversely impact machinery,personnel,and *** main causes of specific problems are the unknown mechanisms of local geothermal formation,inappropriate temperature co.trol measures,and insufficient systematic *** this study,three work sections relating to a high geothermal tunnel are:the tunnel face,middle-of-tunnel section,and outside-oftunnel section.A co.ling strategy is proposed to offer technical support in achieving co.prehensive co.ling,overall as well as for each of the ***,a co.prehensive geological survey explores the mechanism and exact location of the heat ***,grouting and centralized drainage measures are used to co.trol the heat release of hot *** ventilation,ice chillers and other applicable measures are used to co.trol the ambient ***,a monitoring and early warning system is established to prevent *** co.ling strategy has been applied in the field with good results.

关键词： high geothermal tunnels co.ling strategy co.prehensive co.ling measures safety and security

Development and engineering application of integrated safety monitoring systems for China’s high-speed trains

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Transportation Safety and Environment 2024年第2期6卷 36-44页

作者： Yan Zhu Tiantian Wang Ruiyuan Shen Jingsong Xie Jingsong Yang Guoqin Zhang Hongqi Tian Xifeng Liang School of Traffic and Transportation Engineering Central South UniversityChangsha 410075HunanChina CRRC Changchun railway Vehicles co. LtdChangchun 130062JilinChina China State railway Group co. Ltd.Beijing 100084China

With the improvement of the running speed of China’s high-speed trains,the demands for running status monitoring and security assurance of High-speed Electric Multiple Units(EMU)have increased ***,the current safety monitoring systems are independent,which is not co.ducive to the co.prehensive monitoring and information sharing of the whole *** temperature monitoring of running gear is insensitive to early *** to develop a train operation safety monitoring system with strong engineering implementation and high integration is a key problem to be *** the monitoring of running stationarity,frame stability and running gear health of China’s high-speed trains,an integrated safety monitoring system framework is designed,and the logic and algorithm for the diagnosis of stationarity,stability and health states of rotating parts are *** software which fused the temperature,high and low frequency vibration data is developed,and the design and installation of the vibration temperature co.posite sensors are *** research results have realized the integration and co.prehensive processing of multiple monitoring systems,co.pleted the improvement from single co.ponent and vehicle-level safety monitoring to multi-system,train-level and interactive *** the process of real vehicle application,the developed monitoring system acquires the vehicle operation status data accurately and in real *** co.structed diagnosis algorithm and logic evaluates the vehicle operation status accurately and in a timely manner,and avoids the progression from fault to *** research results show that the integrated safety monitoring system can provide technical support for train operation safety.

关键词： electric multiple units(EMU) integrated safety monitoring system stationarity stability fault diagnosis

Research on the cuttings discharge in air cushion chamber of slurry shield based on CFD-DEM co.pling method Author links open overlay panel

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Particuology 2024年第8期91卷 88-105页

作者： Han Wang Wantao Ding Weimin Yang Chengzhen Wang Wenduan Yu Zhicheng Wang School of Qilu Transportation Shandong UniversityJinan250002China China railway 14th Bureau Group co. LtdJinan250101China

The rapid discharge of cuttings from the air cushion chamber is crucial for the co.struction safety and excavation efficiency of the slurry *** studies have mainly focused on the transport characteristics of cuttings in the slurry discharge pipe,while the co.plete process of cuttings entering the slurry discharge pipe from the air cushion chamber until they are discharged was often *** on the CFD-DEM co.pling method and co.bined with actual engineering,this paper established a numerical model that can more co.pletely reflect the cuttings discharge process during slurry shield tunneling,and the effects of the slurry velocity at slurry gate and sco.ring pipes,inclination angle of slurry discharge pipe,cuttings diameter and shape co.fficient were investigated by analyzing the variation in the mass flow rate,mass of discharged cuttings,and discharged *** results revealed that increasing the slurry velocity can promote the discharge of *** keep the discharged rate at a high level,it is reco.mended that the slurry velocity at the slurry gate should be greater than 0.15 m/*** the inclination angle of the discharge pipe is co.ducive to the rapid discharge of *** with large diameter or small shape co.fficient are more prone to accumulate in the air cushion chamber and cause clogging *** research results not only help to improve engineers'understanding of cuttings discharge in slurry shield,but also provide practical guidance for formulating relevant co.struction measures.

关键词： Slurry shield CFD-DEM co.pling method Cuttings discharge Aircushion chamber Slurry discharge pipe

Stratigraphic identification using real-time drilling data

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第9期16卷 3452-3464页

作者： Minglong You Zhikai Hong Fei Tan Hao Wen Zhanrong Zhang Jiahe Lv Faculty of Engineering China University of GeosciencesWuhan430074China China railway Siyuan Survey and Design Group co. Wuhan430063China

Identification of stratigraphic interfaces and lithology is a key aspect in geological and geotechnical *** this study,a monitoring while-drilling system was developed,along with a co.responding data pre-processing *** method can handle invalid drilling data generated during manual *** co.relation between various drilling parameters was analyzed,and a database of stratigraphic interfaces and key lithology identification based on the monitoring parameters was *** average drilling speed was found to be the most suitable parameter for stratigraphic and lithology identification,and when the average drilling speed varied over a wide range,it co.responded to a stratigraphic *** average drilling speeds in sandy mudstone and sandstone strata were in the ranges of 0.1e0.2 m/min and 0.2e0.29 m/min,*** results obtained using the present method were co.sistent with geotechnical survey *** proposed method can be used for realtime lithology identification and represents a novel approach for intelligent geotechnical surveying.

关键词： Monitoring while-drilling Drilling parameters Geotechnical stratigraphy Lithology identification

Experimental study on the co.pression-shear performance of a new-type circumferential joint of shield tunnel

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Underground Space 2024年第1期14卷 138-155页

作者： Ziyang Zhou Kun Feng Yiteng Liu Bohan Wu Chunfang Lu Gang Lin Chuan He Key Laboratory of Transportation Tunnel Engineering of Ministry of Education Southwest Jiaotong UniversityChengdu 610031China China Academy of railway Sciences co.poration Limited Beijing 100081China China railway Eryuan Engineering Group co. Ltd.Chengdu 610031China

To investigate the co.pression-shear behavior of a new circumferential joint based on the sleeve-straight bolt co.bination type co.nection of large-diameter shield tunnels,a series of full-scale joint experiments was carried *** the process of the experiment,more attention was paid to the specimen displacement,bolt stress and joint damage *** the basis of these experiment phenomena,this study discussed the co.pression-shear bearing process of the new co.nector,analyzed the damage mode of the joint structure,and finally evaluated the performance of the new *** is found that the bearing process of the joint can be divided into four stages:the transitional stage for overco.ing the friction of the co.crete,the sleeve bearing stage for the sleeve bearing shear loads alone,the co.bined bearing stage for bearing shear loads by the co.nector system,and the structural damage stage for structural instability and *** speaking,affected by co.nector position and hand hole,the positive co.pression-shear stiffness of the joint is less than the negative co.pression-shear stiffness,and the positive shear strength of the joint is greater than the negative shear *** increase of longitudinal axial force will improve the co.pression-shear performance of the *** relationship between longitudinal axial force and joint stiffness is a logarithmic *** use of new type of co.nector can effectively improve the co.pression-shear stiffness of joints under low shear loads,but the application of straight bolts will lose part of the strength performance.

关键词： Shield tunnel New type of co.nector Shear resistance Full-scale experiment Circumferential joint

Effect of local openings on bearing behavior and failure mechanism of shield tunnel segments

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Underground Space 2024年第3期16卷 183-205页

作者： Xiaojing Gao Pengfei Li Mingju Zhang Haifeng Wang Ziqi Jia Wu Feng Key Laboratory of Urban Security and Disaster Engineering Ministry of EducationBeijing University of TechnologyBeijing 100124China Nantong railway co.struction co.ponent co. LtdNantong 226000China

Local failures(loss of co.crete or reinforcement)can severely co.promise the bearing capacity of shield segments,damaging the tunnel *** investigate the effects of local openings on the bearing behavior and failure mechanism,four full-scale bending tests were co.ducted on specimens with different opening positions and diameters;monitoring of load,displacement,and co.crete strain was performed during *** test results reveal that both the opening position and diameter significantly influence the bearing characteristics of the *** failure process includes four sequential stages distinguished by three critical loads,namely the cracking,failure,and ultimate ***,the numerical model of the local failure segment was established using the elastoplastic damage co.stitutive relation of the co.crete and verified by inversing the full-scale test *** on the numerical model,parametric analyses were performed to co.prehensively investigate the influences of the opening position,co.crete loss,and reinforcement loss on the bending ***,an analytical model was proposed,indicating that the opening position is the primary factor decreasing the bearing capacity,followed by the opening diameter and reinforcement *** results of this study can provide a theoretical basis for the safety assessment and remedial design of subway shield tunnels under extreme breakthrough co.ditions.

关键词： Shield tunnel Local opening segment Bearing behavior Failure mechanism

The effect of friction block hole co.figurations on the brake tribological performance of high-speed trains

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Friction 2024年第10期12卷 2241-2258页

作者： Yuanke WU Wei CHEN Youguang ZHU Zaiyu XIANG Honghua QIAN Jiliang MO Zhongrong ZHOU Tribology Research Institute School of Mechanical EngineeringSouthwest Jiaotong UniversityChengdu 610031China China railway Engineering Equipment Group co. Ltd.Zhengzhou 450016China

Three triangular friction block co.figurations are co.monly employed in high-speed train brake systems,namely,unperforated,perforated co.figuration with one circular hole,and perforated with three circular *** this study,we adopted these friction block types to investigate the effect of perforated friction block co.figurations on the brake performance of high-speed trains based on a self-developed brake test *** results indicate the significant impact of the number of the holes on the wear behavior,temperature distribution,and vibration characteristics of the brake *** friction surface of the unperforated block is co.ered by wear debris,while the perforated blocks produce less wear ***,the one-hole block exhibits a more uniform temperature distribution and better vibration behavior than that with three *** friction brake is a dynamic process,during which separation and attachment between the pad and disc alternatively occur,and the perforated structure on the friction block can both trap and expel the wear debris.

关键词： high-speed train block brake performance wear debris flow

Investigation and measurement of old building response to the overlapped shield tunnel of multiple schemes in the sandy co.ble stratum

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Underground Space 2024年第2期15卷 260-274页

作者： Xue Li Aopeng Geng School of Geoscience and Technology Southwest Petroleum UniversityChengduSichuan 610500China China railway co.struction Bridge Engineering Bureau Group co. Ltd.Tianjin 300300China

Ground movements due to tunneling are beco.ing increasingly critical as buildings are located around co.struction *** study proposes a new co.bined reinforcement method using a foundation grouting oblique pipe *** former improves the bearing capacity of the subsoil,and the latter blocks the transmission of soil deformation,which weakens the influence of co.struction during overlapped tunnel *** on this new method,a case study of the shield tunneling response to an old building in Line 6 of China’s Chengdu Metro is ***,three-dimensional numerical models without reinforcement,traditional foundation grouting reinforcement,and the new co.bined reinforcement schemes were *** numerical simulation performance was verified using a set of field instrumentation data,which demonstrated that the old building response to the overlapped tunnels was under co.trol,and the maximum deformation,angular distortion,and principal tensile strain of the building were 5.25 mm,5.1010–6 rad/m,and 0.0081%,*** with the traditional reinforcement scheme,the deformation,angular distortion,and principal tensile strain in the co.bined reinforcement scheme were reduced by 54.78%,71.02%,and 70.22%,*** results have important implications for the design and co.struction of shield tunnels and their response to old buildings.

关键词： Overlapped tunnels Reinforcement schemes Under-crossing Old building Numerical simulation