Influences of vegetation coverage on hydrothermal change and stability of loess slope in seasonal frozen soil area
The vegetation coverage has a significant effect on the hydrothermal changes of slope soil,and the hydrothermal changes will lead to the change of groundwater level and slope stability.Based on the monitoring data of temperature and water content of soil in vegetation-covered and non-vegetation areas in the Heifangtai slope,the influences of vegetation cover on soil temperature,water content and slope stability were studied in seasonal frozen soil area by means of thermo-hydromechanical coupling numerical model.The results show that:1)The soil in the non-vegetation area has a thicker freezing depth and a longer freezing duration,which promotes the seepage of groundwater to the vegetation-covered area,resulting in higher soil moisture in the vegetation-covered area.2)In the freezing period,the increase of groundwater table in the non-vegetation area is higher than that in the vegetation-covered area.Under the same irrigation conditions,the vegetation-covered area is more prone to landslides,and it's slip surface is steeper.3)The landslides in the vegetation-covered area have the characteristics of gradual retrogressive evolution.The slip surface will occur along the bottom of the groove on the back wall of the landslides,forming a gradual failure mode.