| The compaction degree of soil and the bearing capacity of soil layer after compaction are very important in the rolling process of overlying soil.Roller model for the soil rolling effect has a great impact,this paper is based on the actual engineering projects,engineering projects mainly use the bulk soil for coal seam overlaying,and then use the roller rolling.The compaction degree of soil is very high in the layered rolling and releasing slope.In this paper,combined with the field soil condition,the discrete element analysis software EDEM and finite element analysis software LSDYNA were used to analyze the condition of the soil rolled by the vibration-free roller.The displacement,porosity and density of soil after rolling and the mechanical properties of soil under dynamic load were obtained.The main conclusions of the study are as follows:(1)When analyzing the engineering characteristics of bulk soil,sieve method is used to analyze the soil particle size distribution curve.Coarse sand contains a certain amount of clay particles,but when the soil is scattered,the structure form of the soil is mainly single grain structure.In the process of rolling,the soil particles have a certain cohesion because the soil compactness is improved and the soil particles bond more closely.(2)The discrete element analysis software EDEM was used to simulate and analyze the changes of density,displacement and porosity of the loose soil before and after rolling.With the increase of the overburden thickness,the displacement and density of the soil increased gradually,and the porosity decreased gradually.(3)In the moving process of the steel wheel,there will be a large uplift and lateral extrusion of the soil in front of the steel wheel.The rolling conditions of different soil thickness are analyzed.The maximum uplift height of the steel wheel is 20 cm when the soil thickness is 30 cm,and the lateral extrusion height is 12 cm.It can be concluded that the height of uplift and the extrusion height of lateral soil mass are related to the thickness of overlying bulk soil layer,and there is a maximum height value.(4)In the roller rolling process,the soil particles have a certain velocity in the contact surface with the steel wheel,and the size and direction of the velocity of the particles have a certain regularity.According to the discrete element analysis method,the velocity range of the particle movement has a certain depth,that is,the improved depth.According to the particle migration,the uplift of the front soil and the lateral soil extrusion can be judged.(5)Finite element analysis shows that with the increase of the thickness of the covered loose soil from 15 cm to 60 cm,the peak value of the additional stress exerted by the roller’s steel wheel on the soil decreases gradually.(6)In the finite element analysis,in the process of steel wheel compaction soil,the spatial distribution of vertical stress in soil is similar to the ideal theoretical calculation form,which has a high similarity and can be used to analyze the spatial distribution of stress in the excavation.(7)With the increase of the cohesion or friction Angle of the soil,the uplift height of the front soil and the extrusion height of the lateral soil decrease gradually in the rolling process of the roller.With the increase of shear modulus,the uplift height of the soil in front of the steel wheel and the extrusion height of the soil in the lateral direction increase.With the increase of cohesive force,friction Angle or shear modulus,the additional contact stress of soil increases gradually. |
