Study On Influence Of Vegetation Hydrological Effect On Slope Stability

Loess is the main soil type in the western region of China.Its good permeability,and easily collapsible disintegration characteristics determines that it is susceptible to damage from the natural environment,its stability is very poor.In recent years,with the proposal of vegetation slope protection,planting plants on the slopes can not only satisfy the stability requirements of the slopes,but also meet the requirements of greening and beautifying the environment,it has gradually become the preferred method for controlling soil erosion and protecting slopes.The hydrological effect of plants has the effect of rainfall interception,inhibition of surface runoff,and increase of soil permeability,and the root water absorption and plant transpiration can reduce the pore water pressure.In this paper,the hydrological effect of vegetation is used as the entry point.The following aspects are mainly studied.(1)Combining unsaturated soil theory with heat and moisture coupled non-isothermal flow equations,establish an atmospheric-vegetation-unsaturated soil interaction model,it provides a theoretical basis for the subsequent quantitative analysis of the hydrological effects of vegetation on the stability of slopes.(2)The transpiration of plants can reduce the volumetric moisture content in the soil,thereby increasing the suction and shear strength of the soil and improving the stability of the slope.Finite element software was used to quantitatively analyze the characteristic parameters such as leaf area index(LAI)and root depth range of the plant and analyze its influence on transpiration.The effects of slope height and slope ratio on transpiration and slope stability were analyzed.(3)Under the rainfall-transpiration condition,a comparative analysis of the vegetated slope and the non-vegetated slope was conducted for the homogeneous loess type slope,simulating the influence factors of soil permeability coefficient,rainfall intensity,rainfall duration,rainfall rain type,and groundwater level height of different root soils,the volumetric water content and negative pore water pressure of the soil inside the slope change with time and changes in the safety factor of the slope.(4)Based on the local plant growth conditions,plant characteristics and climatic conditions in Xifan,the dynamic responses of the vegetation to slope stability under long-term conditions are established.Analyze the change curve of volumetric water content,negative pore water pressure and safety factor of the soil inside the slope under the condition of long-term wet-dry cycle,transpiration,evapotranspiration,evaporation and irrespective of vegetation.