多冻土地区块石气冷拓宽路基差异融沉处治效果分析

发布时间：2019-06-09 20:04

【摘要】：为了减少多年冻土拓宽路基差异融沉,提出块石气冷拓宽路基处治方案,在路基下伏多年冻土横向差异退化的背景下,以多孔介质自然对流换热理论为基础,建立了块石拓宽气冷路基数值计算模型,对利用旧路拓宽,以及翻挖旧路并原位新建块石气冷拓宽路基两种不同建设模式进行了数值模拟,分析了块石层内空气对流特征、多年冻土层长期热稳定性变化过程以及新旧地基冻土层差异融沉控制效果。结果表明:块石拓宽路基在提高阳坡路肩下多年冻土层热稳定性方面起到了积极作用,拓宽路肩下多年冻土层在新建黑色沥青路面强吸热作用下未出现明显退化,块石拓宽路基在消除阴阳坡冻土差异退化方面效果明显。在既有旧路病害严重路段,需要对旧路地基和拓宽地基起到双重调控作用,适宜采用翻挖旧路并原位新建块石气冷拓宽路基,对新旧路基差异融沉可以起到更好的控制效果。
[Abstract]:In order to reduce the differential melting settlement of permafrost widening subgrade, a treatment scheme of block gas cooling widening subgrade is put forward, which is based on the theory of natural convective heat transfer in porous media under the background of lateral differential degradation of permafrost under the subgrade. The numerical calculation model of block stone widening air-cooled subgrade is established, and two different construction modes are simulated by using the old road widening, digging the old road and building the block stone air-cooled subgrade in situ, and the characteristics of air convection in the block stone layer are analyzed. The change process of long-term thermal stability of permafrost layer and the control effect of differential thawing settlement of new and old foundation frozen soil layer. The results show that the widening roadbed plays an active role in improving the thermal stability of permafrost layer under Yangpo road shoulder, and the permafrost layer under widening shoulder does not degrade obviously under the strong endothermic action of new black asphalt pavement. The effect of widening subgrade by block stone is obvious in eliminating the difference and degradation of frozen soil on Yin and Yang slopes. In the existing road sections with serious old road diseases, it is necessary to play a dual role in regulating the foundation of the old road and widening the foundation. It is suitable to dig the old road and build a new block gas cooling in situ to broaden the roadbed, which can play a better control effect on the differential melting settlement of the new and old roadbed.
【作者单位】：长安大学;中交第一公路勘察设计研究院有限公司;中国科学院寒区旱区环境与工程研究所冻土工程国家重点实验室;
【基金】：国家科技支撑计划(2014BAG05B07,2014BAG05B03) 国家重点基础研究发展计划(八六三计划)项目(2012CB026106) 中交集团科技研发项目(2011-ZJKJ-16);
【分类号】：U416.1

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