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Analysis of transverse thermal regime difference of high-speed railway roadbed in seasonally frozen regions 15

Analysis of transverse thermal regime difference of high-spe...

15th International Conference of the International Association for Computer Methods and Advances in Geomechanics, IACMAG 2017

作者： Zhang, Yuzhi Wen, An Cheng, Boyuan Key Laboratory for Health Monitoring and Control of Large Structures in Hebei Province Shijiazhuang Tiedao University Shijiazhuang Hebei050043 China

The transverse thermal regime differences are widespread for high-speed railway roadbed in seasonally frozen regions. Based on the monitored data of four typical roadbed sections from Harbin-Dalian high-speed railway in seasonally frozen regions of China, the external influence and heat absorption of roadbed different parts are studied quantitatively through the comparisons of the temperature amplitude and average temperature, and then the characteristics of the frost penetration development are analyzed. The temperature variation laws of the coldest and hottest months with depth are also analyzed. On the basis of the above analysis, the influence factors and potential hazards of the transverse differences are discussed. It is stated that: the west shoulders are most influenced by the external environment. The coldest and warmest month temperatures at a certain depth are characterized by a spindle shape. The increase of the latitude and roadbed height may aggravate the transverse thermal regime difference. In addition, the roadbed transverse thermal difference may induce the uneven roadbed deformation, hence, the roadbed stability and the ride comfort of track structure maybe threated. Therefore, the relevant monitoring and deformation mechanics studies should be further reinforced. © 2017 15th International Conference of the International Association for Computer Methods and Advances in Geomechanics

关键词： Deformation

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Construction of stability monitoring and evaluation system for high-speed railway roadbed in cold regions 8

Construction of stability monitoring and evaluation system f...

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8th International Conference on Structural health monitoring of Intelligent Infrastructure, SHMII 2017

作者： Zhang, Yuzhi Sun, Baochen Zhao, Weigang Wen, An The Key Laboratory for Health Monitoring and Control of Large Structures in Hebei Province Shijiazhuang Tiedao University Shijiazhuang Hebei050043 China

ISBN: (纸本)9781925553055

Along with the development of economy, the high-graded transportation line project are extending towards the cold regions gradually. The high-speed railway (HSR) in cold regions requires extreme high stability, thus the rigorous enigineering demands challenge the roadbed stability severely. The construction of the automatic monitoring and evaluation system of the HSR roadbed in cold regions, to master the safety conditions in real time, will guarantee the safe operation of high-speed train strongly. Through the characteristics analysis of the HSR roadbed in cold regions, the monitoring indices, static deformation combined with dynamic responses, are determined. The layout plan of monitoring points, which integrates the transverse discontinuity with horizontal continuity, is put forward. On the basis of conquering the continous high-precision collection sensors and technology suitable for the severe environment in cold regions, the automatic continous monitoring system of the HSR roadbed is developed, and the evaluation method of roadbed stability based on the on-site data information mining and numerical model is built. The monitoring system and stability method have realized the continous monitoring and stability evaluation of the Harbin-Dalian HSR under the water-heat-load combined action. This will be conductive to provide the scientific support for the stability change mechanism, the operation and maintenance of the HSR roadbed in cold regions. © 2017 International Society for Structural health monitoring of Intelligent Infrastrucure. All rights reserved.

关键词： Railroads

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Research on Remote Automatic monitoring System of High and Steep Slope Based on FBG Tilt Sensor

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IOP Conference Series: Earth and Environmental Science 2019年第4期267卷

作者： Hongbin Xu Feng Li Weigang Zhao Meng Li Yang Gao Bo Zhang School of Civil Engineering Beijing Jiaotong University Beijing 100044 China School of Civil Engineering Wuhan University Wuhan Hubei 430074 China Structure Health Monitoring and Control Institute Shijiazhuang Tiedao University Shijiazhuang 050043 Hebei China Key Laboratory of Structure Health Monitoring and Control of Hebei Province Shijiazhuang Tiedao University Shijiazhuang Hebei 050043 China

A remote automatic monitoring system for high and steep slope based on FBG tilt sensor was established along Shuohuang railway, and an FBG tilt sensor with a high sensitivity was developed in this monitoring system. The monitoring system is running smoothly, and the monitoring results show that the maximum deformation of the slop is less than 2 mm in the rainy season, slope slip occurs at the location of 9.5 meters above, the overall deformation of slope is small, and the slope is steady.

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Effective concrete surface crack detection based on extreme learning machine 8

Effective concrete surface crack detection based on extreme ...

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8th International Conference on Structural health monitoring of Intelligent Infrastructure, SHMII 2017

作者： Wang, Baoxian Zhao, Weigang Zhang, Hao Wang, Xinmin Zhang, Guangyuan Structural Health Monitoring and Control Institute Shijiazhuang Tiedao University Shijiazhuang050043 China Key Laboratory for Health Monitoring and Control of Large Structures Shijiazhuang050043 China Collaborative Innovation Center of Large Infrastructure Disaster Prevention and Reduction of Hebei Province China

ISBN: (纸本)9781925553055

Concrete surface crack detection has been an important field for the safety of civil engineering structure. However, under the background of high-density data acquiring demand, the existing crack detecting methods could not obtain the favorable efficiency and capability. In this work, we present a novel concrete surface crack detector for efficiently dealing with the massive crack images. Specifically, discrete cosine transformation is firstly utilized to extract the frequency domain characteristics of concrete surface images. Then, with the calculated image frequency features, an emergent learning technique (i.e., Extreme Learning Machine) is exploited to find the optimal separate hyper-plane between the crack object and backgrounds. Experiments on the crack images from the railway ballast-less track slab validate the effectiveness of the proposed method. © 2017 International Society for Structural health monitoring of Intelligent Infrastrucure. All rights reserved.

关键词： Frequency domain analysis

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Analysis of void-disease detection in ballastless track of high-speed railway based on directional filter 8

Analysis of void-disease detection in ballastless track of h...

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8th International Conference on Structural health monitoring of Intelligent Infrastructure, SHMII 2017

作者： Yang, Y. Zhao, W.G. Du, Y.L. Tian, X.S. School of Electrical and Electronic engineering Shijiazhuang Tiedao University Shijiazhuang China Key Laboratory for Health Monitoring and Control of Large Structures in Hebei Province Shijiazhuang Tiedao University Shijiazhuang China

ISBN: (纸本)9781925553055

Owing to the concealment of void disease in cement-asphalt (CA) mortar and the requirements for rapidness, ground penetrating radar (GPR) has a good application prospect in detecting disease on a high-speed railway. Track slab, the covering of the CA mortar layer, is a multi-layer reinforced concrete structure;strong reflection of reinforcement makes disease identification difficult. To solve this problem, directional models were established to study the feature difference of echoes between reinforcement and void disease, and a horizontal filter based on curvelet transform was proposed to identify the void disease in CA mortar. Finally, forward simulation was conducted to validate the performance of the presented algorithm. Results show that the horizontal filter method contributes to the identification of void diseases in the CA mortar layer which were located in the middle of the reinforcement group. This study promotes the application of GPR on disease detection in a high-speed railway. © 2017 International Society for Structural health monitoring of Intelligent Infrastrucure. All rights reserved.

关键词： Ground penetrating radar systems

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Experimental research on wind load distribution of four-center-circle coal shed

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Gongcheng Lixue/Engineering Mechanics 2017年 34卷 59-62页

作者： Wang, Xiao-Jiang Zheng, Yun-Fei Liu, Qing-Kuan Liu, Xiao-Bing Ma, Wen-Yong School Of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China Health Monitoring and Control Institute Shijiazhuang Tiedao University Shijiazhuang050043 China HeBei Province Key Lab of Structure Health Monitoring and Control Shijiazhuang050043 China

According to the requirements of engineering design and experimental research, the wind tunnel tests on a large-span coal shed structure for a thermal power plant were carried out. The influence of wind direction angle on wind-load-shape coefficient was studied. After analyzing the shape coefficient of each measuring point under different working conditions, the wind-load-shape coefficients on the structure surface were obtained. The results showed that: the measuring point had the largest volume coefficient when the angle between the measuring point and the incoming wind was among 30 ~ 40 degree;at different wind direction angles, the coefficients at the top and the edge areas of the model were relatively large, therefore, these areas should be strengthened when building a coal shed. © 2017, Engineering Mechanics Press. All right reserved.

关键词： Coal

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Experimental study on wind pressure distribution and wind-induced interference effects on long-span spherical structure

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Jianzhu Jiegou Xuebao/Journal of Building structures 2016年第10期37卷 140-146页

作者： Liu, Qingkuan Lu, Zhaoliang Zheng, Yunfei Ma, Wenyong Liu, Xiaobing Structural Health Monitoring and Control Institute Shijiazhuang Tiedao University Shijiazhuang050043 China Key Laboratory for Structure Health Monitoring and Control in Hebei Province Shijiazhuang050043 China School of Civil Engineering Shijiazhuang Tiedao University Shijiazhuang050043 China

Spherical shell structure is very sensitive to wind loads. The wind load is one of the most important loads in structural design. By wind tunnel tests, simultaneous multi-pressure measurement on surface of spherical shell structure was carried out under different conditions to study the characteristics of wind load distribution and wind-induced interference effects. Results show that opened and closed sunroofs have significant effect on wind pressure distribution on the outer surface of the structure in partial region, especially, leeward side. For the inner surface of the structure, wind pressure become small when sunroof is closed, which is safe for the outer structure. Coal dump has no effect on wind pressure distribution along wind direction, while in cross wind direction it has effect. Different relative positions of adjacent structures have certain influence on wind-induced interference effects and different regions have different effects. © 2016, Editorial Office of Journal of Building structures. All right reserved.

关键词： Wind stress

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Experimental validation of a vertical wheel load measurement system

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International Journal of Simulation: Systems, Science and Technology 2016年第12期17卷 6.1-6.4页

作者： Song, Ying Du, Yanliang Sun, Baochen School of Transportation Institute Shijiazhuang Tiedao University Shijiazhuang City050043 China Hebei Key laboratory of Structure Health Monitoring and Control Shijiazhuang Tiedao University Shijiazhuang City050043 China

A new on-track measuring method for vertical wheel/rail contact force based on PVDF strain sensors is developed, which overcomes the difficulties found in other conventional methods by resistance strain gauges. A rail model for the measurement was made and a laboratory load test using this method was performed to verify the proposed technique. Firstly, the test was performed under the condition that vertical load acts on various points along the rail direction. Secondly, the interference of bending by lateral force on rail surface strain caused by vertical force was investigated. Finally, the expected correlation between vertical wheel/rail contact force and strain responses measured by PVDF sensors was confirmed. The experimental results are perfectly compliant with the theoretical analysis and simulation calculations, which verify that the proposed method has sufficient practicability of monitoring vertical wheel load on commercial lines. © 2016, UK Simulation Society. All rights reserved.

关键词： Loads (forces)

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Analysis on GPR echo signal enhancement algorithm based on subspace sparsity deconvolution

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Journal of Engineering Science and Technology Review 2016年第6期9卷 43-51页

作者： Yong, Yang Yanliang, Du Weigang, Zhao Baoxian, Wang Hao, Zhao School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing100044 China The Key Laboratory for Health Monitoring and Control of Large Structures in Hebei Province Shijiazhuang Tiedao University Shijiazhuang050043 China Department of Urban and Civil Engineering Ibaraki University Hitachi316-8511 Japan

Strong reflection interference of rebar is the main barrier against ground-penetrating radar (GPR) detection of internal diseases in reinforced concrete structure. Deconvolution can strengthen GPR echo data through acquiring structural layer data. However, existing deconvolution echo signal processing algorithms cannot be applied to process the GPR echo data because of the hypothesis that the wavelet is in the minimum phase system, which is inconsistent with the attenuation of GPR wavelet during two-way travel time. To resolve this problem, a new subspace sparsity deconvolution algorithm was proposed in this paper to enhance the echo signal of rebar lower diseases. A wavelet signal attenuation model of layered structure was firstly established to analyse the influencing factors of disease echo signal attenuation under different conditions. On this basis, the sparsity deconvolution algorithm based on wavelet iteration was placed to enhance GPR echo signal quickly by using the constraint condition of subspace errors. The processing of GPR forward simulation data also reveals that the proposed algorithm can inhibit noises effectively and acquire layer information from the concrete structure when the local signal-to-noise ratio is larger than -19.7dB. The proposed algorithm is clearly superior to the existing automatic gain control algorithm with respect to the echo enhancement effect of GPR. Results show that this method overcomes the minimum phase restriction of deconvolution and it is of great significance to detect and recognize inter-layer diseases of high-speed railway ballastless tracks. © 2016 Eastern Macedonia and Thrace Institute of Technology. All rights reserved.

关键词： Concrete construction

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A Novel Rough-Surface Direct Wave Suppression Algorithm b ased on Energy Adaptive Analysis

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Journal of Engineering Science and Technology Review 2016年第4期9卷 202-208页

作者： Yong, Yang Weigang, Zhao Yanliang, Du Hao, Zhang School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing100044 China The Key Laboratory for Health Monitoring and Control of Large Structures in Hebei Province Shijiazhuang Tiedao University Shijiazhuang050043 China Department of Urban & Civil Engineering Ibaraki University Hitachi 316-8511 Japan

As a nondestructive testing technology, ground penetrating radar (GPR) is widely used in the detection and recognition of high-speed railway subgrade diseases. Rough-surface direct wave suppression caused by locomotive vibration and subgrade irregularity is a challenge in the GPR signal process. Flat-surface assumption makes traditional method difficult to apply directly to the rough terrain environment. To remove rough-surface direct wave and improve the signal-to-noise ratio, a new adaptive algorithm is proposed in this paper. First, according to the characteristic of electromagnetic wave propagation, the echo model of GPR was constructed, and the composition of ground radar echo signal was analyzed. Next, the eigenvalue and eigenvector of the echo signal and ground direct wave were studied. With the increase of relative permittivity, the energy eigenvector of direct wave and echo signal converged to the same vector space. On this basis, a rough-surface direct wave suppression framework based on energy feature adaptive analysis was proposed. Finally, a numerical simulation and field experiment were carried out to verify the feasibility of the algorithm. Results showed that the algorithm effectively suppresses the rough ground direct wave, and the processing result preserves the target echo more completely. Without intervention, this method can be applied in automatic direct wave suppression, which will promote the development of automatic identification technology in the detection of railway subgrade diseases. © 2016. Eastern Macedonia and Thrace Institute of Technology. All rights reserved.

关键词： Vector spaces

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