Simulations of undrained tests were performed in a periodic cell using three dimensional(3D) discrete element method(DEM) program TRUBAL.The effective undrained stress paths are shown to be qualitatively similar to pu...Simulations of undrained tests were performed in a periodic cell using three dimensional(3D) discrete element method(DEM) program TRUBAL.The effective undrained stress paths are shown to be qualitatively similar to published physical experimental results of cohesionless media such as sand.Liquefaction and temporary liquefaction are observed for very loose samples and medium loose samples,respectively.A new micromechanical parameter is proposed to identify whether liquefaction or temporary liquefaction occurs in terms of a redundancy factor.The relationship of redundancy factor and average coordination number is derived theoretically.It is demonstrated that the phase transition dividing the solid-like behaviour and liquid-like behaviour is associated with a redundancy factor of 1,which corresponds to an average coordination number slightly above 4.展开更多
Non-cohesive soils have been widely used in construction of high-speed railway for their excellent physical and mechanical properties,and the determination of maximum and minimum dry density of such soils containing o...Non-cohesive soils have been widely used in construction of high-speed railway for their excellent physical and mechanical properties,and the determination of maximum and minimum dry density of such soils containing oversize particles is an important topic.In this study,the influence of oversize particles on dry density of non-cohesive soils is investigated by packing tests.Test results show that oversize particles will make"extra"voids around their surfaces,which increase significantly if the size ratio of oversize material to matrix material is not very big.The dry density of the total material will be overestimated by Elimination Method due to the omission of the"extra"voids.Thus,a geometric model is proposed by which the"extra"voids can be taken into account,and a new oversize correction method for non-cohesive soils is developed.Test results confirm the applicability of this method on the condition of oversize fraction being less than 40%by mass.展开更多
基金Project(GR/R91588) supported by the Engineering and Physical Sciences Research Council,UK
文摘Simulations of undrained tests were performed in a periodic cell using three dimensional(3D) discrete element method(DEM) program TRUBAL.The effective undrained stress paths are shown to be qualitatively similar to published physical experimental results of cohesionless media such as sand.Liquefaction and temporary liquefaction are observed for very loose samples and medium loose samples,respectively.A new micromechanical parameter is proposed to identify whether liquefaction or temporary liquefaction occurs in terms of a redundancy factor.The relationship of redundancy factor and average coordination number is derived theoretically.It is demonstrated that the phase transition dividing the solid-like behaviour and liquid-like behaviour is associated with a redundancy factor of 1,which corresponds to an average coordination number slightly above 4.
基金supported by the National Basic Research Program of China("973"Project)(Grant No.2013CB036204)
文摘Non-cohesive soils have been widely used in construction of high-speed railway for their excellent physical and mechanical properties,and the determination of maximum and minimum dry density of such soils containing oversize particles is an important topic.In this study,the influence of oversize particles on dry density of non-cohesive soils is investigated by packing tests.Test results show that oversize particles will make"extra"voids around their surfaces,which increase significantly if the size ratio of oversize material to matrix material is not very big.The dry density of the total material will be overestimated by Elimination Method due to the omission of the"extra"voids.Thus,a geometric model is proposed by which the"extra"voids can be taken into account,and a new oversize correction method for non-cohesive soils is developed.Test results confirm the applicability of this method on the condition of oversize fraction being less than 40%by mass.
