Utilizing the Discrete Element Method,this research studied the stiffness distribution of gap-graded soils by modifying the conventional static method.By acknowledging the inherent particle property disparity between ...Utilizing the Discrete Element Method,this research studied the stiffness distribution of gap-graded soils by modifying the conventional static method.By acknowledging the inherent particle property disparity between coarser and finer particles,this research differentiates the stiffness distribution of gap-graded soils from the perspective of contact and particle types.Results indicate that particle property disparity significantly influence the small-strain stiffness characteristics,consequently altering the overall stiffness distribution in gap-graded soil specimens.Specifically,with the equivalent coarser particle property,an increase in particle Young's modulus of finer particles results in an augmentation of small-strain stiffness values,alongside an increased stiffness distribution contribution from finer particles.Nevertheless,this study reveals that even with a higher particle Young's modulus of finer particles,the proportion of small-strain stiffness transferred by finer particles remains consistently lower than their volume fraction.Furthermore,the proportion of stiffness transferred by finer particles may fall below their contribution to stress transmission.This investigation accentuates the subtle yet significant effects of particle property variations on small strain stiffness and its subsequent distribution,providing a foundation for advancing the significance of particle property disparities in evaluating soil responses.展开更多
The design procedure of a dense gap-graded friction course（DGGFC） with coarse aggregate void filling method is presented. Testing results show that a DGGFC mixture possesses a dense stone-matrix structure, good stab...The design procedure of a dense gap-graded friction course（DGGFC） with coarse aggregate void filling method is presented. Testing results show that a DGGFC mixture possesses a dense stone-matrix structure, good stability and almost the same texture depth as stone matrix asphalt （SMA）. It also has a coarse and even surface after paving and has no separation during construction. It is durable and impermeable. It balances and improves the inherent inconsistency of asphalt mixture between the large texture depth for skid resistance and the impermeability for durability. The actual application in the Nanning-Liuzhou Expressway also shows that the performance of the DGGFC is as excellent as that of SMA, while the DGGFC mixture is cheaper than SMA. The DGGFC mixture is good for wearing course of pavement. Further research on DGGFC can be helpful for improving the surface skid resistance, prolonging the life-span period and reducing the construction costs of asphalt pavement.展开更多
Suffusion in gap-graded soil involves selective erosion of fine particles through the pores formed by coarse particles under seepage forces.As the fines content(FC)decreases,the hydraulic and mechanical behavior of th...Suffusion in gap-graded soil involves selective erosion of fine particles through the pores formed by coarse particles under seepage forces.As the fines content(FC)decreases,the hydraulic and mechanical behavior of the soil will change,posing a huge threat to engineering safety.In this study,we first conduct a series of experimental tests of suffusion by using gap-graded soils and then analyze the evolution process of suffusion and the effect of the hydraulic gradient.Subsequently,according to the physical model,a discrete element method(DEM)numerical model with dynamic fluid mesh(DFM)is developed to extend the experimental study to the pore scale.Our results reveal the migration process of fines and the formation of erosion zones.A parametric study is then conducted to investigate the effect of the hydraulic gradient,FC,and K_(0) pressure(which limits the lateral displacement of the sample and applies vertical pressure)on eroded weight.The results show that the eroded weight increases with the increase of the hydraulic gradient and FC but decreases with the increase of K_(0) pressure.展开更多
基金Financial supports from the PolyU Distinguished Postdoctoral Fellowship Scheme are highly appreciatedsupported by the National Natural Science Foundation of China (Grant No.52201008)the Fundamental Research Funds for the Central Universities,the State Key Laboratory of Particle Detection and Electronics (Grant No.SKLPDE-KF-202311).
文摘Utilizing the Discrete Element Method,this research studied the stiffness distribution of gap-graded soils by modifying the conventional static method.By acknowledging the inherent particle property disparity between coarser and finer particles,this research differentiates the stiffness distribution of gap-graded soils from the perspective of contact and particle types.Results indicate that particle property disparity significantly influence the small-strain stiffness characteristics,consequently altering the overall stiffness distribution in gap-graded soil specimens.Specifically,with the equivalent coarser particle property,an increase in particle Young's modulus of finer particles results in an augmentation of small-strain stiffness values,alongside an increased stiffness distribution contribution from finer particles.Nevertheless,this study reveals that even with a higher particle Young's modulus of finer particles,the proportion of small-strain stiffness transferred by finer particles remains consistently lower than their volume fraction.Furthermore,the proportion of stiffness transferred by finer particles may fall below their contribution to stress transmission.This investigation accentuates the subtle yet significant effects of particle property variations on small strain stiffness and its subsequent distribution,providing a foundation for advancing the significance of particle property disparities in evaluating soil responses.
文摘The design procedure of a dense gap-graded friction course（DGGFC） with coarse aggregate void filling method is presented. Testing results show that a DGGFC mixture possesses a dense stone-matrix structure, good stability and almost the same texture depth as stone matrix asphalt （SMA）. It also has a coarse and even surface after paving and has no separation during construction. It is durable and impermeable. It balances and improves the inherent inconsistency of asphalt mixture between the large texture depth for skid resistance and the impermeability for durability. The actual application in the Nanning-Liuzhou Expressway also shows that the performance of the DGGFC is as excellent as that of SMA, while the DGGFC mixture is cheaper than SMA. The DGGFC mixture is good for wearing course of pavement. Further research on DGGFC can be helpful for improving the surface skid resistance, prolonging the life-span period and reducing the construction costs of asphalt pavement.
基金supported by the National Key Research and Development Program of China(No.2020YFC1808102)the National Natural Science Foundation of China(Nos.42077247 and 42002271)。
文摘Suffusion in gap-graded soil involves selective erosion of fine particles through the pores formed by coarse particles under seepage forces.As the fines content(FC)decreases,the hydraulic and mechanical behavior of the soil will change,posing a huge threat to engineering safety.In this study,we first conduct a series of experimental tests of suffusion by using gap-graded soils and then analyze the evolution process of suffusion and the effect of the hydraulic gradient.Subsequently,according to the physical model,a discrete element method(DEM)numerical model with dynamic fluid mesh(DFM)is developed to extend the experimental study to the pore scale.Our results reveal the migration process of fines and the formation of erosion zones.A parametric study is then conducted to investigate the effect of the hydraulic gradient,FC,and K_(0) pressure(which limits the lateral displacement of the sample and applies vertical pressure)on eroded weight.The results show that the eroded weight increases with the increase of the hydraulic gradient and FC but decreases with the increase of K_(0) pressure.
