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冻土层的变化与地 气交接面的能量交换过程有直接的联系.地 气交接面的能量交换过程包含了辐射、对流、热传导三种最基本的热物理过程.利用以此为基础建立的青藏铁路沿线地表和路基表面热力学数值模式(RSTM),将安多站的实测资料作为模式输入,针对梯形路基与边坡朝向和坡度有关的坡面温度变化及两侧坡面温差变化的问题,对无云大气条件下不同坡度和坡向的表面温度变化特征进行了模拟分析.结果表明,对于就地取土修筑的路基而言,安多段路基上表面温度在各季节都高于气温,在夏季具有明显的高表面温度值,尽管在夏季任何坡度和坡向的路基坡面都具有冷却效应,但路基仍处于高温状态;冬季路基上表面温度虽略低于0℃,但路基偏南方向坡面的强烈增温效应,使南坡表面温度远远超过冻土融化温度的临界状态,而路基两侧坡面热效应的相反作用,通过影响冻土层的冻融过程,可能引起路基纵向裂缝的发生.因此,对冻土路基采取有效的防护措施是非常必要的.用实测资料进行的检验表明,RSTM具有良好的模拟性能,对不同防护措施下青藏铁路路基热状况的预测具有良好的应用前景.
The change of permafrost layer is directly related to the energy exchange process of the ground-air interface.The energy exchange process of ground-air interface includes the three basic thermophysical processes of radiation, convection and heat conduction.Based on this, According to the surface temperature and subgrade surface thermodynamic numerical model (RSTM) along the Qinghai-Tibet Railway, the measured data of Anduo Station are input as mode. In view of the slope temperature change and slope temperature change on both sides of the trapezoidal embankment, The results show that the surface temperature of the embankment on the Amdo section is higher than the air temperature in all seasons, In summer, there are obvious high surface temperature values. Although the cooling effect is found on the subgrade slope of any slope and slope in summer, the subgrade is still at high temperature. Although the surface temperature of winter subgrade is slightly lower than 0 ℃, The strong warming effect of the slope makes the surface temperature of the southern slope far exceed the critical temperature of the thawing temperature of the frozen soil and the opposite effect of the thermal effect of the slope on both sides of the subgrade through the shadow The freeze-thaw process of frozen soil layer may cause longitudinal cracks in the subgrade, so it is very necessary to take effective protective measures on the subgrade of frozen soil.Experiments conducted with measured data show that RSTM has good simulation performance, The prediction of the thermal condition of the Qinghai-Tibet Railway embankment under the protective measures has a good application prospect.