季节性冻融过程黄土斜坡地下水响应

Groundwater response of loess slope during seasonal freeze-thaw process

冻融型地质灾害是黄土高原区地质灾害的主要形式之一,在季节性冻融过程中地下水变化是黄土地质灾害的主要驱动因素。选取甘肃省永靖县黑方台典型斜坡,通过野外监测、室内模拟,研究了季节性冻融过程中黄土斜坡地下水的响应过程。通过构建季节性冻融过程黄土斜坡地下水响应数值模型,模拟了季节性冻融过程黄土斜坡水分运移和溢出量变化规律。结果表明,在冻结前期,地下水溢出带溢出量减少,坡脚地下水水位整体略有上升,幅度约1.5 m;在冻结期,黄土斜坡冻结深度扩大,溢出带部分阻塞,地下水位在坡脚抬升,坡脚地下水位最高上升达8.18 m,饱和区持续扩大;在融解期,溢出带逐渐恢复排泄,斜坡整体地下水位下降,幅度小于2 m,坡脚地下水水位下降显著,饱和区缩小,最终基本恢复至冻结前水平。通过模拟黄土斜坡季节性冻融过程地下水响应全过程,为研究季节性冻融型滑坡失稳机理提供科学依据。

Freeze thaw geological hazards are one of the main forms of geological disasters in the Loess Plateau.Groundwater changes are the main driving factors of geological disasters in the process of seasonal freezing and thawing.In this paper,the response process of groundwater in Loess Slope during seasonal freeze-thaw process was studied by field monitoring and indoor simulation.Based on the numerical model of groundwater response in Loess Slope during seasonal freeze-thaw process,the variation law of water movement and spillover of loess slope during seasonal freeze-thaw process was simulated.The results show that in the early stage of freezing,the overflow amount of groundwater in the overflow zone decreases,and the groundwater level at the foot of the slope rises slightly,with an amplitude of about 1.5m;in the freezing period,the frozen depth of loess slope expands,the overflow zone is partially blocked,and the groundwater level rises at the foot of the slope,and the maximum groundwater level at the foot of the slope rises to 8.18m,and the saturated area continues to expand;in the thawing period,the overflow zone gradually recovers to discharge and the slope is straightened The groundwater level of the slope toe decreased significantly,and the saturation area narrowed,and finally recovered to the level before freezing.By simulating the whole process of groundwater response in the process of seasonal freeze-thaw on loess slope,this paper provides scientific basis for studying the instability mechanism of seasonal freeze-thaw landslide.