As one of the major high-speed railway ballastless track structures in China,CRTSIII slab ballastless track has been laid for more than 6500 km.However,there are no detailed studies on its track irregularity deteriora...As one of the major high-speed railway ballastless track structures in China,CRTSIII slab ballastless track has been laid for more than 6500 km.However,there are no detailed studies on its track irregularity deterioration throughout extended service periods,which may threaten the safety and stability of high-speed vehicles(HSV).In this study,a long-term tracking detection of CRTSIII slab ballastless track irregularities has been conducted,revealing its annual evolution law.An HSV-track coupled dynamics model was established to investigate the HSV dynamic responses under annual evolution of track irregularities.Considering the potential deterioration of track irregularities to extremely bad condition,the recommended classified limits for irregularity are proposed by analyzing the limit-exceeding probability of the safety and stability indexes of HSV.The results show that:taking 10 m wavelength as a demarcation,longer-wavelength irregularities exhibit larger amplitudes,faster evolution rates and a linear increasing trend,primarily affecting the stability of HSV.Conversely,shorter-wavelength irregularities exhibit smaller amplitudes and an insignificant evolution trend,predominantly affecting the safety of HSV.Furthermore,the periodic irregularity induced by the arching of 32 m simply-supported beam bridge should be paid closer attention to,as their evolution rate significantly surpasses that of irregularities at other wavelengths.展开更多
The sunny-shady slopes effect is a phenomenon that impacts the temperature distribution of high-speed railway subgrades,resulting in uneven frost heaving deformation on the subgrade surface,which in turn causes static...The sunny-shady slopes effect is a phenomenon that impacts the temperature distribution of high-speed railway subgrades,resulting in uneven frost heaving deformation on the subgrade surface,which in turn causes static irregularity in the slab track.Based on the hydraulics theory,a thermal-hydro-mechanical(THM)coupled model of frozen soil is established and verified.We explore the process and characteristics of the temperature field and deformation of soil during the freezing process of high-speed railway subgrades and analyze the track irregularity variation law of China Railway Track SystemⅢslab tracks under uneven frost heaving deformation.The results show that,because the left and right slopes of high-speed railway subgrade are exposed to different amounts of solar radiation,which is the key factor causing uneven frost heaving of subgrade.Different strike angles cause changes in temperature of the subgrade’s upper part and the frost heaving amount on the surface,leading to differences in the deformation of the slab track structure:Increased strike angle weakens the rail level irregularity of the down line and marginally increases the rail level irregularity of the up line,and these become consistent in north-south directions.Therefore,when selecting railway lines in seasonal frozen areas,the west-east direction should be avoided to prevent the extremes in sunny-shady slopes effect on subgrades.展开更多
In this paper, we consider the problem of irregular shapes tracking for multiple extended targets by introducing the Gaussian surface matrix（GSM） into the framework of the random finite set（RFS） theory. The Gaussi...In this paper, we consider the problem of irregular shapes tracking for multiple extended targets by introducing the Gaussian surface matrix（GSM） into the framework of the random finite set（RFS） theory. The Gaussian surface function is constructed first by the measurements, and it is used to define the GSM via a mapping function. We then integrate the GSM with the probability hypothesis density（PHD） filter, the Bayesian recursion formulas of GSM-PHD are derived and the Gaussian mixture implementation is employed to obtain the closed-form solutions. Moreover, the estimated shapes are designed to guide the measurement set sub-partition, which can cope with the problem of the spatially close target tracking. Simulation results show that the proposed algorithm can effectively estimate irregular target shapes and exhibit good robustness in cross extended target tracking.展开更多
基金Project(2022YFB2602900)supported by the National Key Research and Development Program of ChinaProject(K2022T002)supported by the Scientific Research Plan of China Railway。
文摘As one of the major high-speed railway ballastless track structures in China,CRTSIII slab ballastless track has been laid for more than 6500 km.However,there are no detailed studies on its track irregularity deterioration throughout extended service periods,which may threaten the safety and stability of high-speed vehicles(HSV).In this study,a long-term tracking detection of CRTSIII slab ballastless track irregularities has been conducted,revealing its annual evolution law.An HSV-track coupled dynamics model was established to investigate the HSV dynamic responses under annual evolution of track irregularities.Considering the potential deterioration of track irregularities to extremely bad condition,the recommended classified limits for irregularity are proposed by analyzing the limit-exceeding probability of the safety and stability indexes of HSV.The results show that:taking 10 m wavelength as a demarcation,longer-wavelength irregularities exhibit larger amplitudes,faster evolution rates and a linear increasing trend,primarily affecting the stability of HSV.Conversely,shorter-wavelength irregularities exhibit smaller amplitudes and an insignificant evolution trend,predominantly affecting the safety of HSV.Furthermore,the periodic irregularity induced by the arching of 32 m simply-supported beam bridge should be paid closer attention to,as their evolution rate significantly surpasses that of irregularities at other wavelengths.
基金Projects(2021YFF0502100,2021YFB2600900)supported by the National Key R&D Program of ChinaProjects(52022085,52278461)supported by the National Natural Science Foundation of ChinaProject(22CXTD0051)supported by Sichuan Youth Science and Technology Innovation Team,China。
文摘The sunny-shady slopes effect is a phenomenon that impacts the temperature distribution of high-speed railway subgrades,resulting in uneven frost heaving deformation on the subgrade surface,which in turn causes static irregularity in the slab track.Based on the hydraulics theory,a thermal-hydro-mechanical(THM)coupled model of frozen soil is established and verified.We explore the process and characteristics of the temperature field and deformation of soil during the freezing process of high-speed railway subgrades and analyze the track irregularity variation law of China Railway Track SystemⅢslab tracks under uneven frost heaving deformation.The results show that,because the left and right slopes of high-speed railway subgrade are exposed to different amounts of solar radiation,which is the key factor causing uneven frost heaving of subgrade.Different strike angles cause changes in temperature of the subgrade’s upper part and the frost heaving amount on the surface,leading to differences in the deformation of the slab track structure:Increased strike angle weakens the rail level irregularity of the down line and marginally increases the rail level irregularity of the up line,and these become consistent in north-south directions.Therefore,when selecting railway lines in seasonal frozen areas,the west-east direction should be avoided to prevent the extremes in sunny-shady slopes effect on subgrades.
基金supported by the National Natural Science Foundation of China(6130501761304264+1 种基金61402203)the Natural Science Foundation of Jiangsu Province(BK20130154)
文摘In this paper, we consider the problem of irregular shapes tracking for multiple extended targets by introducing the Gaussian surface matrix（GSM） into the framework of the random finite set（RFS） theory. The Gaussian surface function is constructed first by the measurements, and it is used to define the GSM via a mapping function. We then integrate the GSM with the probability hypothesis density（PHD） filter, the Bayesian recursion formulas of GSM-PHD are derived and the Gaussian mixture implementation is employed to obtain the closed-form solutions. Moreover, the estimated shapes are designed to guide the measurement set sub-partition, which can cope with the problem of the spatially close target tracking. Simulation results show that the proposed algorithm can effectively estimate irregular target shapes and exhibit good robustness in cross extended target tracking.
