岛状多年冻土路基年周期性侧向位移试验研究

在岛状多年冻土区,冻土路基的自适应侧向变形季节性特征较明显,当变形过大时,极易诱发纵裂、滑坡等严重的路基病害,因此准确掌握该类路基侧向位移的规律特征,是提高公路设计质量、保障公路安全通行的关键。因此,以实际工程为依托,选取代表性路基试验断面,通过对工后一年内路基土体侧向位移的试验观测,发现岛状多年冻土路基年周期性侧向位移具有明显的阶段性特点。其中,由于水分迁移导致的位移累积曲线近似呈S状,年周期内路基侧向变形最大位置一般位于路基活动层附近;根据试验结果的对比分析,揭示了冻土上限覆土厚度、含水率对路基侧向位移的影响作用。

Experimental Study of Annual Periodic Lateral Displacement of Patchy Permafrost Subgrade

The seasonal characteristics of self-adaptively lateral deformation of permafrost subgrade are more obvious in patchy permafrost regions,and when the lateral deformation is too large,it\s very easy to bring about a series of serious subgrade damages such as longitudinal cracking,slope sliding,so precisely understand the characteristics and laws of lateral displacement of patchy permafrost subgrade is the key to improve design quality and ensure traffic safety.Therefore,in the paper,based on practical project and representative test sections,through experimental observation of lateral displacement to each sections in one year after the project completion,the obvious stage characteristics of annual periodic displacement process of patchy permafrost subgrade are revealed,the cumulative displacement curves show the approximate model of"S"shape because of moisture migration,and the position of largest lateral deformation generally appears near the active layer of subgrade in the annual duration.According to the comparative analysis of experimental results,the effect of covering thickness and moisture of permafrost table on lateral subgrade displacement are find out.