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As the highest altitude and the longest plateau railway line, the Qinghai-Tibet railway passes through a large area of continuous permafrost. As the key position of the combination of roadbed and bridge, the stability and strength of the bridge approach directly affect the smoothness of the whole line. Through an indoor model test, the distribution pattern of space temperature field and the change law of temperature measuring points in the bridge approach of gravel sandwich are studied. With the increase in the depth from the subgrade surface, the influence of the temperature change in the upper atmosphere decreases gradually at the 2.5-m platform back of the subgrade center section, resulting in an obvious lag in the subgrade. By comparing the temperature measurement data of different bridge approaches of the gravel interlayer road bridge and the bridge approach of the U-shaped block gravel road bridge, it is shown that the U-shaped structure not only has a better overall cooling effect, but also the cooling effect gradually increases with the increase in the distance from the abutment back. The influence range of the road-bridge transition section on the spatial temperature field is approximately 14 m in the back of the abutment, and the influence range at 7.5 m is the most severe. The research results have important practical significance and engineering application value for the operation and maintenance of the Qinghai-Tibet railway. [ABSTRACT FROM AUTHOR]

Wind and sand disasters frequently impact the newly constructed railroad along the Hongyi line in Qinghai Province's Qaidam Basin. The existing wind and sand prevention measures, primarily comprising polyethylene (PE) nets, have shown limited effectiveness. To this end, this study introduces an innovative combined sand barrier: A new type of porous sand fixing bricks (PSBs) are made from local aeolian sand, arranged in a square grid like low vertical sand barrier, and combined with a high vertical porous mesh plate (PMP) to form a combined sand barrier. Wind tunnel experiments were conducted to optimize the combined sand barrier's structure. The results indicate that incorporating porous sand-fixing brick sand barrier (PSBSB) on the leeward side of the PMP substantially impacts the near-surface flow field and plays a crucial role in decreasing wind velocity while enhancing sand control. The PSBSB with five rows of PSBs, positioned 18H from the PMP's leeward side, maximizes windproof and sand control efficiencies. Notably, the PSBs exhibit excellent self-stability under wind load, eliminating the need for additional fixing measures. This combined sand barrier presents a replicable, cost-effective solution for wind-blown sand disaster prevention in aeolian sand regions like the Hongyi line, promising advancements in sand barrier technology. • Innovative sand barrier using porous bricks and mesh plates improves sand control. • Optimal barrier design: 5 rows of bricks, 18H from mesh, 93.27% sand suppression. • Combined barrier offers cost-effective, replicable solution for aeolian regions. [ABSTRACT FROM AUTHOR]