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为了研究保温护道对拓宽路基温度场的先期影响,根据青藏公路保温护道试验路观测数据,对冻土地温和冻土上限变化过程进行分析,通过建立拓宽路基有限元模型,在考虑护道对冻土层产生先期影响的基础上,计算路基拓宽对路肩下多年冻土热稳定性的影响。结果表明:阳坡侧的保温护道加速了下伏冻土层的退化,高温冻土区阳坡侧的护道对冻土层的影响大于低温冻土区,阴坡侧护道对冻土层热稳定性影响较小;阳坡侧护道对冻土层产生预融效果,使得阳坡侧路基拓宽后路肩下冻土上限未出现明显下降,产生一种预拓宽的效应,对拓宽路基稳定性有利;阴坡侧护道对路基拓宽热稳定性影响较小,无论先期有无护道,路基拓宽后路肩下冻土上限变化过程无明显差异。
In order to study the proactive influence of thermal insulation on the temperature field of widened embankment, according to the observation data of the test road of the thermal insulation embankment on the Qinghai-Tibet Highway, the change process of the upper bound of the temperate and frozen soil in the frozen soil is analyzed. Based on the finite element model of broadening embankment, Permafrost on the basis of the pre-impact of permafrost, the influence of roadbed broadening on the thermal stability of permafrost beneath road shoulder is calculated. The results show that the thermal insulation on the sunny side of the slope accelerates the degradation of the underlying permafrost layer, and the influence of the protection road on the sunny side in the permafrost zone is more than that of the permafrost zone. Layer thermal stability of the impact of small; Yang slope side of the road to the frozen soil pre-thawing effect, making the sunny side slope widened after the roadside frozen soil did not appear significantly lower limit, resulting in a widening effect of premature broadening of the embankment The stability of slope is beneficial. The protection of the shady side guardrail has little effect on the thermal stability of the roadbed. No significant difference is found in the variation of the upper limit of the frozen soil under the road shoulder when the roadbed is widened.