多年冻土区路基铺设保温护道的目的在于削弱边坡热侵蚀作用对路基下多年冻土温度状况的影响,防止多年冻土上限特别是阳坡侧冻土上限下降,减少人为活动对路堤坡脚及附近天然地表的破坏;防止路侧地表积水渗入基底;对边坡产生反压,防止路肩滑塌,以保证路基的稳定.结合试验工程监测资料,采用数值模拟方法分析了青藏铁路多年冻土区路基保温护道的效果,结果表明:保温护道并没有达到设计的目的,由于路基和护道几何形状对空气对流和太阳辐射的影响,不仅达不到保护冻土地基的目的,反而加大阴阳坡温度差异,导致路基病害的发生. The purpose of laying thermal insulation roadbed in permafrost embankment is to weaken the influence of slope thermal erosion on the temperature conditions of permafrost under roadbed and to prevent the permafrost upper limit, Foot and near the natural surface damage; prevent surface water on the roadside infiltration into the basement; counter-pressure on the slope to prevent the landslide in order to ensure the stability of roadbed.Combined with the monitoring data of the test project, the numerical simulation method was used to analyze the Qinghai-Tibet Railway for many years The results show that the thermal insulation does not achieve the purpose of design. Due to the influence of the geometric shapes of the roadbed and guardrail on air convection and solar radiation, it not only fails to protect the foundation of frozen soil, Instead, increase the temperature difference between the yin and Yang slope, resulting in the occurrence of roadbed disease.