Discrete Element Analysis Of Reinforced Soil Interface And Reinforced Structures

Reinforced earth structure usually refers to a composite structure composed of soil and reinforced materials.After adding reinforcement,the defects of insufficient tensile strength and low soil strength can be significantly improved,and the bearing capacity and overall stability of reinforced soil can be improved..The function of reinforced-soil interface is a key factor influencing the bearing capacity of reinforced soil structure.The function of the interaction between reinforcement and soil depends to a large extent on the bulk properties of the soil and the properties of the reinforcement.However,most scholars are currently based on the assumption of the continuity of the reinforcement medium.The study of the action of the earth on the reinforcement.In view of this,based on the results of the existing laboratory tests,the discrete element PFC3 D program was used to fully consider the granularity of the soil and the contact between the soil particles and the reinforcement.Based on the research results of the existing macroscopic experiments,the mesostructures were considered.A series of PFC3 D discrete element numerical analysis method was established for the series of reinforced-earth structures to reveal the meso-scopic load transfer mechanism and the meso-scopic evolution law of interface parameters.The main research content is as follows:(1)In order to investigate the numerical results of the triaxial test influenced by the apparent shape of the particles,clump particles with different sphericity were used to simulate the sand particles,and the influence factors of the shear strength of the soil samples with different sphericity particles on the soil samples were analyzed.Reveal the meso-mechanism of the interface effect of triaxial specimens reinforced by geogrids.The results show that the particle shape is one of the main factors affecting the physical properties of soil.The shear strength of reinforced soil samples decreases with the increase of particle sphericity,and the displacement in soil samples increases with the increase of the number of reinforced layers.The number of small soil particles increases,that is,the lateral restraint ability of the grid to the soil particles gradually increases,the more full of the interface between the reinforcement and the soil,the cohesion and internal friction angle of the sample decrease with the increase of the sphericity of the particles.It shows that the greater the sphericity value under the same conditions,the smaller the shear strength of soil samples.(2)Based on the conventional tensile test,the particle flow simulation of the unconfined and confined tensile tests was performed using the discrete element PFC3 D program,and the change of the mesoscopic parameters during the stretching of the grating under two conditions was explored.,Analyze the particle displacement characteristics of the reinforced soil interface.The test shows that compared with the indoor unconfined tensile test,the tensile strength of the grid under the overburden load is obviously increased in the lateral tensile test,and the strain is significantly reduced when the grid is at equal strength compared to the unconfined one.Small;With the increase of the overburden load,the ultimate tensile strength increases,and this difference is positively correlated with the strain;During the process of the geogrid stretching,the internal force of the grid is along the grid grain from left to right Progressively,while the internal force transmission effect gradually decreases with distance from the extension end.(3)Using the discrete element PFC3 D program to simulate a large direct shear test,establish a corresponding particle flow model,according to the indoor test results to calibrate the relevant meso parameters,and then adjust the angle between the reinforcement and the shear plane,analyze the different angles of the reinforced soil The mechanical properties and shear strength of the material are studied from the microscopic perspective of the formation of a reinforced zone during shearing.When there is a certain angle between the grid and the shear plane,the shear strength at the shear plane of the model is greater than that at the plain soil,and the shear strength at the horizontal plane is reduced when compared with the horizontal plane;The presence of soil particles will reduce the porosity of the soil particles around the grid,increase the density of the soil,and further form a regional reinforced zone,which can effectively improve the shear performance of reinforced structures,and enhance the stability of the soil.