The soil samples of the roadbed slope of the Datong-Xi'an high-speed railway section are taken as the research object. The frost-heave property of the fiber soil of the roadbed slope under a single freeze-thaw cycle is studied, where the fiber's content is taken into account. The distributions of temperature and humidity fields inside the slope are numerically studied, and the coupling transfer of heat and moisture is revealed. The results are helpful for the optimal design of the roadbed slope

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In this paper, carbon fiber/carbon nanofiber strengthening nonmass concrete slab was designed, and ohmic heating (OH) curing was used to promote the strength formation of the slab under −20°C. COMSOL multiphysical field coupling program has been used to simulate the heating process of nonmass concrete slabs under different conditions. COMSOL analysis results showed that the optimal loading power density of OH cured sample under −20°C was 1000 W/m2∼1200 W/m2. Moreover, numerical analysis results were experimentally validated by the multipoint temperature measurement method. Furthermore, the mechanical properties showed that the compressive strength of the sample cured by 2 days OH curing at −20°C reached up to 48.2 MPa. SEM analysis exhibited that OH curing could improve the interfacial transition zone (ITZ) between the fiber and the matrix, leading to a denser microstructure. This study proved that COMSOL program could provide good theoretical guidance for OH cured nonmass cement concrete under subzero temperature. This work establishes an accurate guideline for electric power supplementation, laying a solid foundation of winter construction with high efficiency and low energy consumption.

The influence of the surrounding building topography of the Datong-Xi?an high-speed railway foundation on the wind environment and the thermal comfort is studied, especially the outdoor wind environment and indoor air-flow organization of the surrounding buildings are analyzed numerically, and the building terrain and the indoor temperature and the wind?s speed distribution are systematically evaluated. The results show that the surrounding terrain of the roadbed has a significant effect on the wind environment of the site, affecting the natural ventilation in summer and wind-proof and energy-saving in winter. The terrain surrounding of the building in summer reduces the wind speed by 30.5%, and it increases in winter by 31.6%; the wind speed in the indoor personnel activity area of the building around the roadbed is less than 0.35 m/s, leading to a comfortable body feeling.