Search Results (4)

Railway system insulators are affected by pollution, altitude, and other environmental situations during operation, which causes reduced electrical performance or even flashover accidents. These factors threaten the safety of railway operations in high-altitude areas. However, the natural contamination characteristics of a railroad in a plateau area is still unclear. In this study, a natural pollution accumulation test for railway insulators in a high-altitude area was carried out, and the distribution rules of nonsoluble deposit density (NSDD), equivalent salt deposit density (ESDD), NSDD/ESDD ratio, and nonuniformity (T/B) of the pollution distribution of the tested insulators were calculated. Meanwhile, the chemical compositions of the pollution from different test sites were analyzed. The differences of pollution accumulation between railway insulators and suspended insulators of a power system and the influencing factors were compared and analyzed by combining with a numerical simulation. The results show that the pollution level of railroad insulators is mainly distributed in level b and above. A pollution sample is mainly composed of sodium chloride, while the NSDD/ESDD ratio of pollution is mostly distributed from 0 to 5, with T/B value ranges from 1/0.62 to 1/1.76. The amount of insulator contamination is influenced by the location inside and outside the tunnel. Additionally, the pollution amount is influenced by the structure and type of insulators. Finally, this paper studies the creepage distance and structural height required by railway insulators in a plateau area according to the natural pollution accumulation characteristics of railway insulators, which can provide a reference for a railway electrical external insulation configuration in a high-altitude area. Full article

One-third of the Earth in China is formed by Karst topography, which exposes different Karst landforms in three topography grades from southeast to northwest, corresponding to below several hundred meters for the first grade, one to two thousand meters for the second grade, and more than 4000 m for the in Qinghai-Tibet Plateau. Through the hydrochemical and D-¹⁸O stable isotopes of 64 water samples collected along two railway lines and the topography fractal characteristics of three typical Karst areas in different topography grades, the changes in Karst development degree, changes in groundwater activities, and the influence of tunnel excavation effects on groundwater environment were analyzed. The results indicated that: (1) the Karst development degree and the influence of Karst tunnel excavation on the groundwater environment are somehow similar in the first and second grades, while there are significant differences between the slopes area from second to third grade and the third grade area. (2) In detail, the relatively weaker Karst development degree and flow seeping in the second grade relatively weaken the influences of tunnel excavation, including the distribution pattern of water resources, the groundwater flow field, and water circulation, while the tunnel elevation has little room to rise. (3) There are many large faults in the north-southward direction in the third topography grade, and the transportation lines in the eastern-western direction will inevitably encounter them. In the intersection area, the tunnel excavation has great effects on the groundwater environment. (4) The lighter hydrogen and oxygen isotopes are enriched in Karst water from the first grade to the third grade, indicating that the recharge source of Karst water presents obvious elevation effect. Full article

Under China’s modern development concept, it is necessary to promote the application of electric equipment to improve the construction environment of high-altitude railway tunnels and to address the efficiency reduction in high-altitude construction of traditional fuel oil equipment. Based on the analysis of the development status of electric equipment for tunneling projects in China, a tripartite evolutionary game approach is used to establish the game payment matrix of the government, equipment manufacturers, and construction units. The impact of the relevant parameters on the tripartite strategy is investigated based on numerical simulations. It has been shown that in the early stages of popularization and application, the government should actively regulate and control, and in the later stages of popularization and application, the government should play a leading role in market mechanisms. Evolutionary stability strategies are affected by the brand revenue that manufacturers earn through technological innovation on electric equipment and the additional research and development costs that need to be paid. The conclusions of this study can help provide a reference for the promotion and application strategy of electric equipment in China’s plateau railway tunnels. Full article

As China’s railways continue to expand into the Qinghai–Tibet Plateau, the number of deep-buried long tunnels is increasing. Tunnel-damaging geothermal disasters have become a common problem in underground engineering. Predicting the potential geothermal disaster areas along the Yunnan–Tibet railway project is conducive to its planning and construction and the realization of the United Nations Sustainable Development Goals (SDGs)—specifically, the industry, innovation and infrastructure goal (SDG 9). In this paper, the Yunnan–Tibet railway project was the study area. Landsat-8 images and other spatial data were used to investigate causes and distributions of geothermal disasters. A collinearity diagnosis of environmental variables was carried out. Twelve environmental variables, such as land surface temperature, were selected to predict potential geothermal disaster areas using four niche models (MaxEnt, Bioclim, Domain and GARP). The prediction results were divided into four levels and had different characteristics. Among them, the area under receiver operating characteristic curve (AUC) and kappa values of the MaxEnt model were the highest, at 0.84 and 0.63, respectively. Its prediction accuracy was the highest and the algorithm results are more suitable for the prediction of geothermal disasters. The prediction results show that the geothermal disaster potential is greatest in the Markam-Deqen, Zuogong-Zayu and Baxoi-Zayu regions. Through jack-knife analysis, it was found that the land surface temperature, active faults, water system distribution and Moho depth are the key environmental predictors of potential geothermal disaster areas. The research results provide a reference for the design and construction of the Yunnan–Tibet railway project and associated sustainable development. Full article