Study On Laboratory Model Experiment Of Rainfall Infiltration Law Under Different Loess Slope Ratios

The loess plateau is a disaster area with frequent landslide accidents in China.Rainfall is one of the main factors affecting slope instability and slope Geological disasters.Therefore,it is very important to understand the infiltration law and mechanism of rainfall in the loess slope.The author designed the indoor slope rainfall model box and artificial rainfall system by himself.With reference to a field homogeneous loess slope in Qingyang,Gansu Province,the model of indoor homogeneous loess slope was established under the condition of satisfying the similar premise of similar theory.Rainfall infiltration test of slope with three slope ratios under four different rainfall intensities was carried out.The data and phenomena of water content,substrate suction,slope surface morphology and wetting front were monitored and recorded in the experiment.The rainfall infiltration and erosion laws under different working conditions were analyzed.At the same time,the numerical model of the same size was established and simulated by using Geo-studio,and the experimental results were verified.The main findings of the study include the following:(1)In view of the current shortage of indoor artificial rainfall equipment,this paper has designed a "atomized rainfall" system with strong controllability,good uniformity and high degree of atomization.In terms of raindrop size,rainfall distribution,landing speed and intermittent spraying,it has effectively improved the shortage of rainfall methods in the past,and ideally simulated the rainfall characteristics of natural rainfall in the wild.(2)In this paper,in order to solve the problem of material similarity in the model test,the control factor of rainfall infiltration-the similarity of permeability coefficient,combined with the properties of the powder clay on the prototype slope,is used to control the dry density of this type of soil.Under the condition that the density and gravity acceleration similarity ratio is 1 and the geometric similarity ratio is N,the similarity criterion of the permeability coefficient similarity ratio is n1/2,which satisfies the similar conditions of the test material,and is the key to the similarity of the scale model test phenomenon.(3)This paper has developed and designed a rainfall slope model box on its own.During the rainfall test,rainwater oozes from the surface of the slope to form a wet front.The change of wet front can be directly observed and measured through the glass box wall of the model box.The rainfall infiltration law is summarized,and the experimental phenomenon shows that the infiltration depth of rainfall is different in different positions of the slope,the infiltration depth of the foot of the slope is the largest,the infiltration depth of the top platform is the largest,and the infiltration depth of the middle slope is the smallest;The infiltration rate of rainfall is different in different positions on the surface slope,the infiltration rate of the top platform is the largest,the infiltration rate of the foot of the slope is the largest,and the infiltration rate of the middle slope is the smallest.(4)The same rainfall conditions are applied to the slopes of three groups of different slope ratios.The experimental results show that the larger the slope ratio,the more obvious the slope erosion failure,and the smaller the slope slope,the more full the rainfall infiltration;Four different rainfall conditions are applied to the same slope.The experimental results show that the greater the rain intensity,the more obvious the slope surface erosion effect,the greater the rainfall infiltration depth,the faster the water content response of the soil at the same time,and the faster the infiltration rate.