Study On The Influence Of Particle Size Gradation Of Iron Ore Fine On Liquefaction

In 2011,the International Marine Solid Cargos Code is enforced by the International Maritime Organization,but ship capsize accident caused by easy-liquefied cargoes still occur from time to time.Cargos are divided into different groups according to experience,but the expression of the mechanism of liquefaction are not given in the code.Refering to many studies in recent years,it has been found that easy liquefied is an inherent property of goods,and particle size grading is the most influential factor.Therefore,it is essential to distinguish the goods of different groups and have certain reference significance for the grouping of unknown goods.In this paper,iron ore is used as the research objects of the study,combining physical experiments and numerical simulations,to study the effect of particle size grade on the properties of easy liquefied.In this paper,the Australian Pb fine was used as the research object,seven different sizes of particle size grades were prepared for dynamic triaxial tests to study the effect of particle size on liquefaction.The influence of particle size on liquefatiction are not simplely linear relationship.When the average particle size is about 0.07～0.8mm,the soil sample is easily liquefied,and when average size is greater than 0.8mm,the liquefaction resistance will be stronger with larger average particle size,And when average particle size is less than 0.07mm,the liquefaction resistance will be larger.Through the dynamic triaxial test,we can get the similar result as simulation.Then four iron ore mines are subjected to particle analysis test to determine the particle size gradation,and according to the relevant test procedures,the liquefaction resistance of these four kinds of iron ore fines can be used to preliminariliy determine the degree of liquefaction of easy-flowing goods,and propose the preliminary granulation according to the average particle size of the cargoesBased on the established numerical model in the three-dimensional particle flow software PFC3D(Particle Follow Code),the macroscopic liquefaction characteristics can be characterized by the contact force,coordination number,effective stress and porosity of the particles through theoretical,experimental and numerical simulation analysis,the microscopic mechanism of liquefaction were concluded.