Research On Numerical Simulation Of Force Transmission During Compactions Loess Based On DEM

Northwest China,North China,and parts of Northeast China are all located in the Loess Belt.In accordance with the principle of adapting to local conditions and taking materials locally,such areas will use a large amount of loess as filling materials in road paving and backfilling foundations.Due to the engineering properties of the loess’ s unusual soils,once improperly disposed of in the project will cause irreversible adverse effects on the structural properties of the entire fill and the superstructure,the compaction process and quality of the loess are particularly important.In order to analyze the stress transfer law of the soil during the compaction process under different compaction conditions,DEM was used to study the variation of the particle velocity field during the compaction process of the loess and the formation process of the force chain,revealing the force in the compaction process of the loess from a mesoscopic perspective Transmission law.The main research results of this article are as follows:(1)Based on particle flow theory and indoor triaxial shear test and indoor click test,the authenticity and reliability of the model are verified by comparison with indoor click test data,which lays the foundation for subsequent research.(2)In the process of compaction,the formation of the force chain always slows the movement of the particles.After the particles move into contact with the non-moving particles,a terminal force chain is formed,and then the load is transmitted to the end of the force chain to cause the peripheral particles Movement,began to enter the next force chain formation process.(3)Under the same click work and the same number of compactions,with the gradual increase of the loosening thickness,there are fewer and fewer strong chains in the sample.When the loosening is too thick,only some weak chains are formed between the sample particles.Because the thickness of the sample layer is too large and there are too many sample particles,the impact load can be easily offset by the friction between the sample particles.(4)Under the same number of compaction times and the same loose paving thickness,when the click power is large,the sample can reach the compaction state faster,and the strength chain of the sample after compaction is smaller than that of the single click power.sturdy.The interaction forces between particles are greater.(5)Under the same click function,when the loose thickness of the sample is small,the sample can be quickly covered with strong chains under less times of compaction,and then with the increase of the number of compactions,the shape of the sample force chain basically does not occur Change,the speed of the particles during the compaction process no longer changes,the sample has formed a rigid body-like structure,the relative position of the internal particles no longer changes;when the thickness of the loose paving is moderate,as the number of compactions increases,it can be obvious The movement trajectory of the particles under different compaction times is observed.In the initial compaction process,the particles in the middle of the sample move before the particles in other parts.During the next compaction process,the particles on both sides of the sample are under the action of the upper particles.At the beginning of the movement,the middle particles are relatively stable.During the compaction process,the particles on both sides of the sample are relatively stable,and the speed of the middle particles is accelerated.This means that the movement of the sample particles during the compaction process is not synchronized.The state of the sub-regional movement,the particles in different regions successively circulate until the sample under the click function is compacted;when the thickness of the loose spread is large,with the number of compactions Large sample can not form an effective chain strong,weak force only some chain during flooding,the work described in the current sample click Although real hit,but the interaction between the particles is weak,can not form a strong chain.It can be seen that the sample has the best compaction thickness under a certain click force,that is,the sample can form a strong chain full of the sample under the appropriate number of compactions,and the sample structure is relatively stable.