Experimental Study On Infiltration Erosion Of Gravel Soil

Under the influence of water infiltration,geotechnical structures such as earth-rock dams and dykes often cause osmotic damage such as piping and flowing soil.In severe cases,the overall instability of the building will occur.The main reason is that the internal structure of the gravel soil structure is infiltrated by osmosis.Erosion eventually leads to the destruction of the soil structure.The indoor experiment and numerical simulation method are used to study the seepage erosion of gravel soil,explore the erosion mechanism and reveal the erosion law,which has theoretical significance and practical value for in-depth study of the penetration stability of geotechnical buildings.Firstly,by summarizing the research results of existing soil infiltration and erosion,the disintegration test device for gravel soil was developed.Secondly,using this device,the osmotic erosion test of gravel soil considering the factors of particle gradation,gravel size,compactness and osmosis slope is carried out.The results show that under the condition of equal coarse grain content,the size of gravel is more Large,the smaller the critical hydraulic gradient,the larger the flow rate,the more the total amount of sand,the more obvious the movement of fine particles,and the worse the stability of penetration resistance.When the dry density is different,the lower the dry density,the poor resistance to penetration of the sample.The decrease in density will significantly reduce the critical hydraulic gradient,although it also increases the total amount of sand,but the impact is relatively small compared to the critical hydraulic gradient and flow rate.Thirdly,the triaxial shear strength test of reconstructed gravel soil under different erosion conditions was carried out.The results show that the internal friction angle and cohesive force of the shear strength index of the gravel soil are reduced after the osmotic erosion.Its cohesive force is reduced more.Thereafter,the Fish and Python programming language was used to calculate the fluid-solid coupling of the gravel soil by PFC3D-CFD.The results were consistent with the results of the indoor penetration test of the gravel soil.Finally,the numerical simulation of PFC3D in the triaxial test of gravel soil was carried out,and the results were basically consistent with the results of the indoor triaxial test.