Operation And Maintenance Level Evaluation Of High-speed Railway Lines Based On Engineering Vulnerability Catastrophe Theory

High-speed railways are susceptible to structural damage and functional deterioration such as roadbed damage,settlement and deformation due to the large geographic range,complex geological environment,frequent disasters and other natural factors,coupled with high operational density and high traffic speeds,resulting in operational safety and speed limits,which has become a key bottleneck for the current operation of high-speed railways.Therefore,this paper focuses on the disaster risk of the operating environment,the settlement of the roadbed and the smoothness of the track,etc.,and takes the study of"engineering vulnerability" as the conceptual framework,equates the external operating environment and the engineering body of the high-speed railway as "disaster-causing body and disaster-bearing body" respectively,and constructs a disaster model based on the disaster theory of engineering vulnerability for the extraordinary disaster risk and the normal service state faced by the operation and maintenance of the high-speed railway.This paper carries out the evaluation of the operation and maintenance level of high speed railways by means of site survey,Geographical Information System(GIS),Interferometric Synthetic Aperture Radar(InSAR),track inspection vehicle dynamic inspection monitoring,theoretical analysis and evaluation calculation.The evaluation of operation and maintenance levels,while compensating for the drawbacks of the existing methods such as the difficulty in producing convergence closure results,achieves downward compatibility and supplementary validation of the current monitoring and evaluation results,which is of great significance to the dual objectives of ensuring operational safety and high speed.The research results of this paper enrich the connotation of the concept of engineering vulnerability and realise its development from point structure to line area engineering,which helps to achieve the dual objectives of high speed railway operation safety and high speed.The main research work and results of this paper are as follows:(1)Based on catastrophic theory,this paper considers that the disaster prevention and control(extraordinary maintenance)and line smoothness monitoring(normal maintenance)faced by the long-term operation of high-speed railways are similar to the disaster-causing process,and compares the external operating environment of high-speed railways to the"disaster-causing body" and the engineering characteristics of high-speed railways to the"disaster-bearing body".(2)By means of data collection and GIS,a system of operational environmental hazard and vulnerability indicators for the study area was constructed.Considering that the study area is located in a low mountainous area,the frequency and intensity of disasters are lower than those in a high mountainous area,but the population density in the area is high,the disaster-bearing bodies are more vulnerable and the prevention and control measures are insufficient.(3)Settlement and TQI monitoring of the Hunan section of the Shanghai-Kunming High Speed Rail using SBAS-InSAR technology and dynamic inspection of rail inspection vehicles.The average settlement of the line was 2.31mm and the maximum settlement was 14.3mm,with the TQI values fluctuating within the range of 2 to 3mm,with most of the individual indicators exceeding the limits of "high and low".By comparing the TQI and settlement results of the Hunan section of the Shanghai-Kunming High Speed Railway,there is a mismatch between the "small settlement but large TQI" and "large settlement but small TQI" conditions,resulting in inconsistent ratings of the two monitoring results,making it impossible to derive a convergent basis for operation and maintenance decisions.(4)Taking the Hunan section of the Shanghai-Kunming high-speed railway as the engineering background,introducing the theory of engineering vulnerability to disasters,selecting the disaster-causing factors of the high-speed railway operating environment and multiple index factors such as settlement and TQI,establishing a comprehensive evaluation index system for the operation and maintenance level of high-speed railway lines,obtaining a comprehensive operation and maintenance level of "medium and medium-low"results,and comparing with the results of non-standard and normal operation and maintenance for verification.The conclusion shows that the evaluation results of the comprehensive level of operation and maintenance of high-speed rail can be compatible with the evaluation of the risk of high-speed rail operating environment,the degree of disease of high-speed rail infrastructure such as settlement and TQI,and the evaluation results are more in line with the engineering reality,which can make up for the disadvantages of the existing methods that make it difficult to produce convergence closure results,achieve the downward compatibility and supplementary verification of the existing monitoring methods and evaluation results,and leapfrogs the concept of engineering vulnerability studies from point structures to line-domain engineering.