Study On Permeability Evolution Of Coarse-Grained Soil Under Seepage Failure Condition

The coarse grained soil has the advantages of low compressibility and high shear strength and bearing capacity.It is a common foundation soil and dam material.However,due to the relatively large particle size,and the adhesion and impermeability is weak,soil particles easily under the action of seepage gradually loss,the formation of progressive damage deformation,as the slope of the main safety hazards.Therefore,it is of practical significance to study the mechanism of particle migration under the condition of infiltration and deformation.Based on the physical test basis,the discrete element software PFC3D is developed,and the numerical simulation of the seepage process is carried out.The results are combined with the physical test The results show that the numerical simulation is carried out by using the vertical osmometer to carry out the infiltration deformation test and the lateral compression test The results are analyzed and the seepage fine rule is obtained.The results show that:1.In Physical test,the process of osmotic damage can be divided into osmotic damage and skeleton mechanical damage process.The variation of permeability coefficient,porosity and compressive modulus can quantitatively describe the damage behavior.In the experiment,there were phenomena such as particle runout,froze,and cracks.And the greater the content of fine particles,the more the phenomenon of osmotic deformation,the damage caused by the damage caused by the more severe damage.2.The migration behavior of the fine particles under the action of the permeation force will produce the osmotic compaction effect in the relatively dense area of the percolation path,and the osmotic compaction zone will be formed,which will lead to the decrease of the local porosity,the decrease of the permeability coefficient,Sex can be short-term promotion,followed by increased penetration in the crowded area was broken.3.In the process of numerical experiment,there are phenomena such as particle runout,large area particle discharge and crack of specimen,which are similar to the physical test phenomenon.The fine particle content has the same effect on the infiltration deformation of numerical specimen.4.The evolution process of the permeability parameters of the specimen is similar to that of the physical experiment The phenomenon of particle migration and osmotic compaction is highly reduced.Therefore,the meso-numerical method of PFC3D can reproduce the osmotic deformation process of coarse-grained soil.