214国道不同路面形式下碎石护坡工程效果实测分析

Engineering Effect of Crushed Rock Revetment of Embankments with Asphalt and Concrete Pavements along the National Highway 214

沥青路面和水泥路面是214国道江河源段采用的两种基本路面形式,由于该路段地处高温不连续多年冻土区,碎石护坡等多种工程措施被尝试用来稳定冻土路基.对两种路面形式下碎石护坡路段的地温监测资料进行综合分析发现,碎石护坡能显著降低路基边坡坡面的年平均温度,减小路基边坡坡面温度的年较差,并对坡脚、路肩和路基中心具有从大到小的冷却作用,但并不能有效减少路基左右两侧的阴阳坡差异.对于采用沥青路面的路基而言,碎石护坡仅能减缓路基下地温上升速率,但并不能阻止路基下冻土升温;水泥路面增设碎石护坡以后,尽管地温也有所上升,但同沥青路面相比地温升幅较小,路基下多年冻土基本保持稳定.对两种路面形式下碎石护坡路段的变形监测资料进行综合分析发现,完工2a后的路面沉降变形量都在10～20cm之间,采用沥青路面的路基变形量略大于采用水泥路面的路基变形量.就不同坡向所产生的变形来看,无论沥青路面还是水泥路面,靠近阳坡一侧的路基变形量均大于阴坡.

Asphalt and concrete pavements are the two essential pavements adopted in the headwaters along the National Highway 214（G214）,where crushed rock revetment is applied widely,because the road is located in the warm discontinuous permafrost regions.In order to well understand the cooling effect of crushed rock revetment on the embankment with asphalt and concrete pavements,a testing field was established between K369＋100 and K370＋000 of the G214.More than two years data from the testing field show that the annual mean temperature at the slope surface declined significantly and the annual range reduced a lot.Cooling effect of crushed rock revetment was more and more significant from the embankment centre,the shoulders to the slope toes.For the road with east-west strike,it couldn＇t effectively reduce the ground temperature difference between both sides.For the asphalt pavement,it only slowed down the temperature rising of the roadbed.For the concrete pavement,the ground temperature rose very slightly.Two years after the road was finished,the settlements varied from 10 cm to 20 cm in both asphalt pavement and concrete pavement.The cumulative embankment deformation with asphalt pavement was a little more than that with concrete pavement.Owing to the different solar radiation,the settlement in the south part of an embankment was always larger than that in the north part.The result is expected to be applied to the highway construction in permafrost regions with asphalt and concrete pavements in the future.