多年冻土地区冻融循环下路基变形规律研究

Embankment Deformation Law Under Freeze-thaw Conditions in Permafrost Regions

为研究多年冻土地区路基在冻融循环下的变形规律,考虑水的相变作用,对路基非稳态温度控制方程、应力-变形基本方程和温度-应力耦合方程进行了推导,并以祁连山中高山区山前斜坡地带某段多年冻土路基为例,建立数值模型,进行路基多场模拟计算,结果表明:融化和冻结温度场变化是由于外界温度变化引起的,冻结温度场呈上凸形态;路基坡脚和路肩对外界温度变化极为敏感,且阴阳坡存在温度差异,路肩两侧产生x方向的冻胀力,在坡脚因冻胀力的差异产生y方向的应力,应力的差异使得土体内部产生剪切力,导致坡脚和路肩出现纵向裂缝;受外界温度的变化、重力的作用和温度梯度力的影响,路基含水率发生变化,融化状态、冻结状态的路肩总位移随时间缓慢增加。

To understand the embankment deformation law under freeze- thaw cycles,this research deduced the state temperature control equation,stress deformation equations and thermal stress coupling equations under the action of water.The mountain area of Qilian Piedmont slope zone was taken as an example,a finite element model was first developed,the stress field and deformation field of the numerical simulation,the results show that the melting and freezing temperature field variation is due to changes of external temperature,the freezing temperature field shows a convex shape; the embankment slope and shoulder is very sensitive to external temperature changes,and the slopes of the existence of temperature the difference,the frost heaving force produced in x direction on both sides of the shoulder,the stress generated in the y direction due to the difference of slope heave force,the stress difference makes the soil produces shear stress,guide caused by the foot of the slope and the shoulder occur longitudinal cracks are affected by changes in ambient temperature,gravity effect and temperature gradient force.