Study On The Mechanism Of Vegetation Slope Stability Under Strong Wind-Load

China,mainly mountainous areas and vast with complex geology,is one of the most serious geological disaster countries in the world.Geological disasters are natural phenomena occurring on the surface under human activities and geological action.The main forms of disasters are landslide,collapse,debris flow,ground collapse,unstable slope and ground cracks.The slippery slope has the highest proportion in the geological calamity in our country,which is the most main kind of geological calamity in our country.The southeast coastal areas of China are criss-crossed by mountains,mostly hilly and heavily vegetated.Due to the climate and geographical location,the annual precipitation is abundant and often affected by typhoons,leading to frequent landslide disasters Therefore,this thesis takes the red soil slope in Longyan area of Fujian Province as the research object to study the deformation and slip mechanism of the slope under wind load and precipitation.The main research contents of this thesis are as follows:(1)The geometric simplified models and root distribution parameters of Chinese fir,bamboo and Masson pine were obtained by investigating and analyzing the characteristic tree species in the study area.Based on the distribution characteristics of Wind-Load,model parameters of characteristic vegetation and the action mode of wind load on vegetation,the stress of vegetation under wind load was obtained.By comparing the mechanical properties of vegetation,the strength of root-soil complex and the force of wind load,the overturning and breaking of different vegetation under the action of strong wind and the load of the slope root-soil complex under the corresponding wind are obtained.(2)Aiming at the physical properties and permeability coefficient of Fujian red loam under different vertical stresses,mechanical properties of natural water content of red loam under 50 kPa,100 kPa,150 kPa and 200 kPa were tested by Shear TracⅢ direct shear apparatus and variable head soil permeability test apparatus.The shear strength of the red loam at 20%,25%,30%,35%,40% and 50% moisture content at 50 kPa,75 kPa and 100 kPa was tested.The experimental characteristics of the internal friction Angle of the red loam decreased gradually with soil water content,and the cohesion first increased and then decreased with moisture content.The permeability coefficient of red loam soil in natural state was measured and the influence of wind load on slope load was investigated experimentally.(3)The fluid-structure coupling model of FLAC3 D vegetation slope was established to study the change law of soil displacement field and seepage field of plain soil slope and vegetation slope under various natural conditions,such as whether the slope is under wind load and different rainfall conditions.The influence law of vegetation slope under different vegetation coverage and different rainfall conditions on the displacement of slope monitoring points,moisture content and safety factor were revealed,and the variation law of vegetation slope stability under the influence of different vegetation under wind and rainfall conditions was summarized.The stability of slope under different tree density,height,precipitation duration and drainage conditions were analyzed,and the protective measures and suggestions of vegetation slope were put forward.There are 78 figures,34 tables and 88 references.