Evolution Law Of Non-uniform Seepage Flow In A Slope With Dual Structure Of Gravel Soil-clay

In the internal and dual structure of the soil slope,the non-uniform seepage field of the strong space variability of the gravel soil is affected by the flow of the water layer(clay)surface,which can influence the stability of the slope,and the relevant research can help to deepen the understanding of the mechanism of the destruction of the gravel slope.However,the research on the mechanism and seepage rule of the surface of the gravel soil and its underlying contact surface is not perfect.Therefore,the research focuses on several scientific problems of the internal seepage properties of the gravel soil binary structure,and the non-uniform flow patterns and particle migration characteristics of the flow field of the gravel soil are analyzed based on the basis of the gravel soil reform.The effect of the seepage system on the stability of the gravel soil and clay slope is revealed in the case of the water network seepage system under different rainfall.The results of the main research are as follows:(1)Using three kinds of the existing internal stability determination criterion of non-viscous soil(H/F single variable decision、Wan & Fell multiple variables decision、fine particle content single variable decision),the applicability of multi-group soil seepage test data is determined,and the main control factors of gravel soil stability are revealed by data statistics and theoretical analysis,and the new guidelines for the determination of gravel flow are established.The results show that the common criterion is high in the miscalculation of gravel.The proportion of uneven uniformity,scale of particle size,the content of fine grain and the porosity of soil porosity have important influence on the surge of gravel.Considering the combination of the influence factors of gravel soil,the criterion of the existing fine particle content is improved,and when the soil uniformity coefficient is greater than 80 or less than 20,the uneven uniformity coefficient is the primary inducer,and when the soil uniformity coefficient is not between 20 and 80,the ratio of the soil size of the soil is mainly the inducer.(2)Using computational fluid mechanics(CFD)and computational fluid mechanics and discrete meta-coupling theory(CFD-DEM),the flow characteristics of the binary structure of gravel soil and the pattern of grain loss are studied,and the formation mechanism and distribution characteristics of the flow channel of gravel flow channel are revealed,the relationship between the average speed and the maximum velocity of the seepage field and the influence of the soil structure parameters on the seepage ability are analyzed.The study shows that the flow velocity of the soil is characterized by the variation of the linear to nonlinear(Darcy flow-Non-darcy flow).The porosity and the loss of fine particles is increased with the flow time and hydraulic gradient,the smaller the particle size of the migration particle,the greater the migration velocity,the gravel soil-the clay contact area is susceptible to the erosion of the flow channel.The large location of gravel soil in continuous pore is easily shaped into a stable seepage channel,and the nearby pore space has a channel branch,and the distribution is larger.Soil structure parameters affect the osmotic capacity of the water,the proportion of coarse grain content and porosity are mainly compared to the permeability of the large pore content,the higher the large pore content and the higher the size of the grain,the better the shape of the grain,the more the water permeability.(3)Based on the distribution characteristics of seepage channels of pipeline network studied above,the seepage system of pipeline network in Anxi gravel soil slope engineering is constructed,and the control ability of the seepage system of pipeline network on the stability of gravel soil slope under different rainfall conditions is analyzed by using the finite element method.The results show that the seepage channel of the pipe network has the most obvious effect on the stability of the slope at the initial stage of rainfall,but the seepage system of the pipe network fails under the condition of long time heavy rainfall or heavy rainstorm,and the slope will be in an unstable state.If the seepage system of the slope pipe network is partially damaged,the drainage capacity of the seepage channel of the pipe gushing decreases sharply.With the increase of rainfall intensity and duration,the seepage channel will fail first compared with the intact state.