The pile-supported subgrade has been widely used in high-speed railway construction in China.To investigate the ground vibrations of such composite foundation subjected to moving loads induced by high-speed trains(HST...The pile-supported subgrade has been widely used in high-speed railway construction in China.To investigate the ground vibrations of such composite foundation subjected to moving loads induced by high-speed trains(HSTs),three-dimensional(3D)finite element method(FEM)models involving the pile,pile cap and cushion are established.Validation of the proposed model is conducted through comparison of model predictions with the field measurements.On this basis,ground vibrations generated by HSTs under different train speeds as well as the ground vibration attenuation with the distance away from the track centerline are investigated.In addition,the effects of piles and pile elastic modulus on ground vibrations are well studied.Results show that the pile-reinforcement of the subgrade could significantly contribute to the reduction of ground vibrations.In particular,the increase of elastic modulus of pile could lead to consistent reduction of ground vibrations.However,when the pile elastic modulus is beyond 10 GPa,this benefit of pile-reinforcement on vibration isolation can hardly be increased further.展开更多
China’s high-speed railways are always facing the potential damage risk induced by strong earthquakes.And the route design concept of“using bridge instead of embankment”has also greatly increased the probability of...China’s high-speed railways are always facing the potential damage risk induced by strong earthquakes.And the route design concept of“using bridge instead of embankment”has also greatly increased the probability of high speed trains moving on bridges when a strong earthquake happens.In the past decades,a bunch of theoretical and numerical studies have been conducted in the seismic dynamic field of high-speed railway.However,the effective dynamic test system for verifying the given method and theoretical results is still lacking.Therefore,a novel dynamic test system(DTS)consisting of a shaking table array and a train-pass-bridge reduced-scale model is proposed in this paper.Through some crucial technical problems discussion,the effectiveness of similar design scheme and the feasibility of reduced-scale DTS are elaborated,and then the detailed DTS structures are given and displayed as part-by-part.On this basis,the demonstration tests are conducted and compared with the numerical simulation.The results show that the proposed DTS is accurate and effective.Therefore,the DTS can provide a new physical simulation approach to study the high-speed train’s running safety on bridges under earthquakes and can also provide a reference for the construction of related systems.展开更多
The initiation and evolution of short-pitch corrugation in Beijing metro line 4 was studied from the viewpoint of wheelset vibration.A three-dimensional elastic model was set up.Numerical simulations were undertaken w...The initiation and evolution of short-pitch corrugation in Beijing metro line 4 was studied from the viewpoint of wheelset vibration.A three-dimensional elastic model was set up.Numerical simulations were undertaken with this model to analyze the corrugation by the wheelset vertical vibration and torsional vibration.Based on numerical results,the relation between rail corrugation and wheelset vibration,and the relation between the position of electromotor and wheelset vibration were indicated.It is found that avoiding the wheelset-rail resonance is one method of controlling the rail short-pitch corrugation and solving the vibration and noise problem in metro lines.展开更多
In order to study the dynamic response of the rail embankment under different speeds and moving load of following vehicles,a model experiment with a ratio of 1:10 is established to test the time history of acceleratio...In order to study the dynamic response of the rail embankment under different speeds and moving load of following vehicles,a model experiment with a ratio of 1:10 is established to test the time history of acceleration and the earth pressure of the embankment at various train speeds.Using the ABAQUS finite element calculation software,a train load is applied through the FORTRAN subroutine,thereby establishing a three-dimensional finite element model with the same size as the model experiment.The data and conclusions of the finite element method model are verified by the model experiment.The model also makes some supplements to the model experiment.The experimental results show that with the increase of speed,the peak acceleration and earth pressure of the embankment also increase.By analyzing the experimental data,it can also be found that the vertical acceleration of the embankment is much greater than the axial acceleration and the lateral acceleration.In addition,the elastic modulus of the soil and the sleeper pitch also have some influence on the acceleration.展开更多
An experimental study and theoretical analysis were carried out to explore the ground-borne vibration generated by elevated high-speed railway in rock strata.Taking a typical rail line constructed on rock area in Chin...An experimental study and theoretical analysis were carried out to explore the ground-borne vibration generated by elevated high-speed railway in rock strata.Taking a typical rail line constructed on rock area in China as the research object,a set of field tests was performed on Rizhao-Lankao High-Speed Railway,the bridge and ground vibrations were measured as trains passed at 330−340 km/h,then the transferring law and spatial distribution under individual frequencies were investigated.The experiment results indicate that the bridge frequency spectrum exhibited relatively high-frequency vibration peaks caused by short-wavelength irregularity;ground vibration farther than 30 m away can be amplified with a higher frequency and numerous components.Furthermore,the wave propagation equation of a stratified rock strata was established based on direct-stiffness method to explore the vibration attenuation rules via frequency-domain analysis.It is found that the rock area has a weaker correlation between vibration transmissibility and frequency,thicker and harder rock strata loss their vibration attenuation capacity.It can be concluded that the high-speed railways induced vibration on rock strata shows a wide frequency band and large amplitude,the design of reducing vibration aimed at specific frequency is important according to next more detailed numerical study.展开更多
Results of in-situ vibration measurement carried out at Tianjin West Elevated Railway Station which has the trains running on the station structure were reported. The main excitation source is the train passing throug...Results of in-situ vibration measurement carried out at Tianjin West Elevated Railway Station which has the trains running on the station structure were reported. The main excitation source is the train passing through the station. Vibration measurements were recorded in the vertical direction of the supporting track beam, the platform and the steel truss beam of the waiting hall, as well as in the vertical, longitudinal and transverse directions of the roof arch base of the station. Acceleration time responses were obtained. The maximum value, vibration level and one-third octave band RMS spectra of the measured accelerations were studied. The propagation of vibration in different structural floors was discussed. The influence of train speed, distance to the vibration source and the type of train on the structural vibration were analyzed. Results show that the vibration level increases with the train speed, while it attenuates with the distance to the track. Furthermore, the vibration responses of different structural floors were compared, and it is noted that the vertical vibration of the bottom slab of the platform is most severe and the transverse vibration of the roof arch base is the smallest. The results provide reference on the vibration characteristics and vibration energy distribution of this type of "Train on building frame" system used as an elevated railway station.展开更多
基金Project(51978510)supported by the National Natural Science Foundation of China。
文摘The pile-supported subgrade has been widely used in high-speed railway construction in China.To investigate the ground vibrations of such composite foundation subjected to moving loads induced by high-speed trains(HSTs),three-dimensional(3D)finite element method(FEM)models involving the pile,pile cap and cushion are established.Validation of the proposed model is conducted through comparison of model predictions with the field measurements.On this basis,ground vibrations generated by HSTs under different train speeds as well as the ground vibration attenuation with the distance away from the track centerline are investigated.In addition,the effects of piles and pile elastic modulus on ground vibrations are well studied.Results show that the pile-reinforcement of the subgrade could significantly contribute to the reduction of ground vibrations.In particular,the increase of elastic modulus of pile could lead to consistent reduction of ground vibrations.However,when the pile elastic modulus is beyond 10 GPa,this benefit of pile-reinforcement on vibration isolation can hardly be increased further.
基金Projects(51878674,52108433,52022113) supported by the National Natural Science Foundation of ChinaProject(2019RS3009) supported by the Hunan Innovative Provincial Construction,China+2 种基金Project(2021JJ40587) supported by the Hunan Provincial Natural Science Foundation of ChinaProject(21B0309) supported by the Research Foundation of Education Bureau of Hunan Province,ChinaProject(HSR202004) supported by the Open Foundation of National Engineering Research Center of High-Speed Railway Construction Technology,China。
文摘China’s high-speed railways are always facing the potential damage risk induced by strong earthquakes.And the route design concept of“using bridge instead of embankment”has also greatly increased the probability of high speed trains moving on bridges when a strong earthquake happens.In the past decades,a bunch of theoretical and numerical studies have been conducted in the seismic dynamic field of high-speed railway.However,the effective dynamic test system for verifying the given method and theoretical results is still lacking.Therefore,a novel dynamic test system(DTS)consisting of a shaking table array and a train-pass-bridge reduced-scale model is proposed in this paper.Through some crucial technical problems discussion,the effectiveness of similar design scheme and the feasibility of reduced-scale DTS are elaborated,and then the detailed DTS structures are given and displayed as part-by-part.On this basis,the demonstration tests are conducted and compared with the numerical simulation.The results show that the proposed DTS is accurate and effective.Therefore,the DTS can provide a new physical simulation approach to study the high-speed train’s running safety on bridges under earthquakes and can also provide a reference for the construction of related systems.
基金Project(C11H00021) supported by Beijing Municipal Science & Technology Commission of ChinaProject(KCJB11063536) supported by Beijing Jiaotong University,China
文摘The initiation and evolution of short-pitch corrugation in Beijing metro line 4 was studied from the viewpoint of wheelset vibration.A three-dimensional elastic model was set up.Numerical simulations were undertaken with this model to analyze the corrugation by the wheelset vertical vibration and torsional vibration.Based on numerical results,the relation between rail corrugation and wheelset vibration,and the relation between the position of electromotor and wheelset vibration were indicated.It is found that avoiding the wheelset-rail resonance is one method of controlling the rail short-pitch corrugation and solving the vibration and noise problem in metro lines.
基金Project(2018YFE0207100)supported by the National Key R&D Program of ChinaProject(52078426)supported by the National Natural Science Fundation of China+4 种基金Projects(2020YJ0253,2020YFSY0060,2019JDRC0133,2019JDRC0134)supported by the Sichuan Provincial Science and Technology Support Project,ChinaProject(K2019G009)supported by the Science and Technology Research and Development Plan of China National Railway Corporation LimitedProjects(SY2016G003,N2020T004)supported by the China National Railway Group Co.Ltd.Scientific Research ProjectProject(LNTCCMA-20210109)supported by the Key Laboratory of New Technology for Construction of Cities in Mountain Area,ChinaProject(2021M692689)supported by the China Postdoctoral Science Foundation。
文摘In order to study the dynamic response of the rail embankment under different speeds and moving load of following vehicles,a model experiment with a ratio of 1:10 is established to test the time history of acceleration and the earth pressure of the embankment at various train speeds.Using the ABAQUS finite element calculation software,a train load is applied through the FORTRAN subroutine,thereby establishing a three-dimensional finite element model with the same size as the model experiment.The data and conclusions of the finite element method model are verified by the model experiment.The model also makes some supplements to the model experiment.The experimental results show that with the increase of speed,the peak acceleration and earth pressure of the embankment also increase.By analyzing the experimental data,it can also be found that the vertical acceleration of the embankment is much greater than the axial acceleration and the lateral acceleration.In addition,the elastic modulus of the soil and the sleeper pitch also have some influence on the acceleration.
基金Project(2016YFE0205200)supported by the National Key Research and Development Program of ChinaProjects(U1734207,51978585)supported by the National Natural Science Foundation of China。
文摘An experimental study and theoretical analysis were carried out to explore the ground-borne vibration generated by elevated high-speed railway in rock strata.Taking a typical rail line constructed on rock area in China as the research object,a set of field tests was performed on Rizhao-Lankao High-Speed Railway,the bridge and ground vibrations were measured as trains passed at 330−340 km/h,then the transferring law and spatial distribution under individual frequencies were investigated.The experiment results indicate that the bridge frequency spectrum exhibited relatively high-frequency vibration peaks caused by short-wavelength irregularity;ground vibration farther than 30 m away can be amplified with a higher frequency and numerous components.Furthermore,the wave propagation equation of a stratified rock strata was established based on direct-stiffness method to explore the vibration attenuation rules via frequency-domain analysis.It is found that the rock area has a weaker correlation between vibration transmissibility and frequency,thicker and harder rock strata loss their vibration attenuation capacity.It can be concluded that the high-speed railways induced vibration on rock strata shows a wide frequency band and large amplitude,the design of reducing vibration aimed at specific frequency is important according to next more detailed numerical study.
基金Project(50938008)supported by the Natural Science Foundation of Beijing,ChinaProject(2012JBM007)supported by the Fundamental Research Funds for the Central Universities,ChinaProject(NCET-11-0571)supported by the Program for New Century Excellent Talents in University,China
文摘Results of in-situ vibration measurement carried out at Tianjin West Elevated Railway Station which has the trains running on the station structure were reported. The main excitation source is the train passing through the station. Vibration measurements were recorded in the vertical direction of the supporting track beam, the platform and the steel truss beam of the waiting hall, as well as in the vertical, longitudinal and transverse directions of the roof arch base of the station. Acceleration time responses were obtained. The maximum value, vibration level and one-third octave band RMS spectra of the measured accelerations were studied. The propagation of vibration in different structural floors was discussed. The influence of train speed, distance to the vibration source and the type of train on the structural vibration were analyzed. Results show that the vibration level increases with the train speed, while it attenuates with the distance to the track. Furthermore, the vibration responses of different structural floors were compared, and it is noted that the vertical vibration of the bottom slab of the platform is most severe and the transverse vibration of the roof arch base is the smallest. The results provide reference on the vibration characteristics and vibration energy distribution of this type of "Train on building frame" system used as an elevated railway station.
