Study On Soil Consolidation And Corrosion Resistance Effect Of Typical Slope Protection Vegetation On Wildcat Landslide In The Three Gorges Reservoir Area

Since the mid to late 20th century,global warming has accelerated the water cycle,leading to increasingly frequent and severe extreme rainfall events,exacerbating the occurrence of secondary disasters such as floods,droughts,and landslides.Since the experimental impoundment of the Three Gorges Reservoir area in 2008,due to the periodic changes in water level,the revival of old landslides and the emergence of new geological disasters in the reservoir area have significantly increased.Landslide accidents caused by extreme rainfall are not uncommon.Therefore,studying the erosion reduction performance of landslides on the bank of the Three Gorges Reservoir area under rainfall conditions is of great significance for the stability of the bank slopes of the Three Gorges Reservoir area.The research results can provide a theoretical reference for soil erosion control on the slopes of the Three Gorges Reservoir Area and for promoting the protection and restoration of ecological environment of the Yangtze River.In order to explore the impact of climate and vegetation coverage changes on the landslide on the bank of the Three Gorges Reservoir Area,this paper takes the wild cat face landslide on the north bank of the Yangtze River in the Three Gorges Reservoir Area as the research object,selects the sliding zone soil and typical undisturbed soil exposed on the slope surface on the site,and through the investigation of the plant population and distribution on the site,selects three typical slope protection vegetation,Bermuda grass,digitaria sanguinalis,and cogon,for tensile test and root composite soil direct shear test,according to the mechanical characteristics of different slope protection vegetation,Select the vegetation with the best slope stabilization effect for cultivation experiments,analyze the growth characteristics of vegetation under different precipitation levels,conduct artificial simulated rainfall experiments on vegetation landslide models,and comprehensively analyze the erosion patterns and deformation characteristics of the Three Gorges Reservoir bank landslides under different rainfall intensities(30,50,90 mm/h)and vegetation coverage(0,25%,50%,75%,90%).The main research results are as follows:(1)The results of tensile test and direct shear test of root composite soil show that the maximum tensile strength and tensile strength of roots of different slope protection vegetation increase and decrease in a power function relationship with the increase of root diameter respectively;Among different slope protection vegetation,the tensile strength of bermuda grass is the highest,while that of cogon is the lowest;Compared to undisturbed soil,slope protection vegetation roots can effectively enhance the shear strength of the soil.Among different vegetation root systems in composite soil,bermuda grass has the highest cohesion,while cogon has the lowest cohesion.(2)Bermuda grass exhibits a unique response pattern to precipitation changes due to its own growth advantage.The cultivation period of 0-30 days is a gentle growth period.Compared to 100 millimetre and 300 millimetre precipitation,the highest growth height of plants can reach5.2 centimetre under 200 millimetre precipitation,indicating that too little or too much precipitation is not conducive to the initial growth of vegetation;Cultivate for 30-90 days and enter a rapid growth period,with plants growing up to a maximum height of 16.3 centimetre under 300 millimetre of precipitation;Under different growth stages,the length,surface area,and volume of vegetation root systems all increase with the increase of precipitation,and their root system indicators reach their maximum values at a precipitation of 300 millimetre.(3)The results of vegetation landslide model tests indicate that the deformation and failure form of the reservoir bank landslide is shallow damage caused by erosion;The overall evolution trend of the surface moisture content of landslides during the rainfall process can be divided into three stages: stable-rapid-gentle.With the increase of vegetation coverage,the change in moisture content at the foot of the slope is the largest;When the rainfall lasts for 30 minutes,the stress on the slope surface increases with the increase of rainfall intensity under different vegetation coverage levels;Under different rainfall intensities,the overall evolution of internal stress at the top of the slope shows an upward trend,but the amplitude of the increase is not significant.The stress variation at the slope body is the largest,while the stress at the foot of the slope is the highest.(4)The results of vegetation landslide model tests indicate that the deformation and failure form of the reservoir bank landslide is shallow damage caused by erosion;The overall evolution trend of the surface moisture content of landslides during the rainfall process can be divided into three stages: stable-rapid-and-gentle.With the increase of vegetation coverage,the change in moisture content at the foot of the slope is the largest;When the rainfall lasts for 30 minutes,the stress on the slope surface increases with the increase of rainfall intensity under different vegetation coverage levels;Under different rainfall intensities,the overall evolution of internal stress at the top of the slope shows an upward trend,but the amplitude of the increase is not significant.The stress variation at the slope body is the largest,while the stress at the foot of the slope is the highest.