Grading-dependency of granular soils

Introduction

Mechanical properties/behaviours are significantly affected by the grain size distribution of the granular soil, which is called “grading-dependency”. The grading change can be induced by grain breakage. Bigger sized grains are easier to be crushed. If the soil is gap-graded, the change of fines content can be induced by seepage force so-called suffusion/internal erosion. Currently, we focuses on how the soil grading evolves, what is mechanical consequence, and how to model the full coupling for engineering design.


Topic 1: Grain breakage effect

Particle crushing often results in more compressibility and less strength for granular assemblies. Therefore, the researches on the influences of particle crushing on the mechanical behavior of soils are important. This topic focuses on how to quantify the amount of particle breakage, how this amount relates to the critical states, and how this amount results in mechanical degradation through laboratory tests, discrete element method, constitutive modelling, and engineering application.



  • Chen WB, Liu K, Yin Z-Y*, Yin JH (2020). Crushing and Flooding Effects on One-dimensional Time-dependent Behaviors of a Granular Soil. Int. J. Geomech. ASCE, 20(2): 04019156.
  • Wang P#, Yin Z-Y* (2020). Micro-mechanical analysis of caisson foundation in sand using DEM: particle breakage effect. Ocean Eng., 215: 107921.
  • Hu W, Yin Z-Y*, Scaringi G, Dano C, Hicher PY (2018). Relating fragmentation, plastic work and critical state in crushable rock clasts. Eng. Geol., 246: 326-336.
  • Jin Y-F#, Yin Z-Y*, Wu Z-X, Daouadji A (2018), Numerical modeling of pile penetration in silica sands considering the effect of grain breakage, Finite Elem. Anal. Des., 144: 15–29.
  • Jin Y-F#, Yin Z-Y*, Wu Z-X, Zhou W-H (2018), Identifying parameters of easily crushable sand and application to offshore pile driving, Ocean Eng., 154, 416-429.
  • Yin Z-Y*, Hicher PY, Dano C, Jin YF (2017). Modeling the mechanical behavior of very coarse granular materials. J. Eng. Mech. ASCE, 143(1): C401600.


Topic 2: Size effect

For granular materials, samples with different grain sizes exhibit different deformability and strength. We have focused on investigating the size effect of granular materials in two aspects: under mechanical loading with significant grain crushing, the sample with bigger grain size has more deformability and less strength, whilst under mechanical loading with few or no grain crushing but significant shear band, the sample with bigger grain size has bigger strength. Our work includes experimental study, discrete element modelling and continuum mechanics modelling up to the engineering application.



  • Yin Z-Y*, Hicher PY, Dano C, Jin YF (2017). Modeling the mechanical behavior of very coarse granular materials. J. Eng. Mech. ASCE, 143(1): C401600.
  • Jiang-Xin LIU (10/2014-03/2018), PhD topic: Numerical study of strain localization in geotechnical structures under the framework of micro-polar theory. (Nantes) Supervisor: Zhen-Yu YIN, Pierre-Yves HICHER


Topic 3: Suffusion effect (internal erosion)

We are investigating the phenomenon of sufussion and its consequences on the mechanical behaviour of soils through CFD-DEM approach. We are also developing a coupled numerical model in the framework of continuum mechanics (a four-constituent numerical approach). The numerical approach has been applied to dike, dam, tunnel with problems of suffusion.




  • Liu Y#, Yin Z-Y*, Wang L, Hong Y (2021). A coupled CFD-DEM investigation of internal erosion considering suspension flow. Can. Geotech. J., DOI: 10.1139/cgj-2020-0099.
  • Xiong H#, Yin Z-Y*, Zhao J, Yang Y (2021). Investigating the effect of flow direction on suffusion and its impacts on gap-graded granular soils. Acta Geotech.. DOI: 10.1007/s11440-020-01012-9.
  • Yang J#, Jin YF#, Yin Z-Y, Laouafa F, Hicher P-Y (2021). Identifying the parameters of a hydro-mechanical model for internal erosion occurring in granular soils by using an enhanced backtracking search algorithm. Eur. J. Environ. Civ. En..
  • Liu Y#, Wang L, Hong Y, Zhao J, Yin Z-Y (2020). A Coupled CFD-DEM investigation of internal erosion of gap graded soil: coupling effect of confining pressure and fines content. Int. J. Numer. Anal. Methods Geomech., 44(18): 2473-2500.
  • Yang J#, Yin Z-Y*, Laouafa F, Hicher P-Y (2020). Three-dimensional hydro-mechanical modelling of internal erosion in dike-on-foundation. Int. J. Numer. Anal. Methods Geomech., 44(8): 1200-1218.
  • Yang J#, Yin Z-Y*, Laouafa F, Hicher P-Y (2020). Hydro-mechanical modeling of granular soils considering internal erosion. Can. Geotech. J., 57(2): 157-172.
  • Yang J, Yin Z-Y*, Laouafa F, Hicher P-Y (2019). Modeling coupled erosion and filtration of fine particles in granular media. Acta Geotech., 14(6), 1615-1627.
  • Yang J#, Yin Z-Y, Laouafa F, Hicher P-Y (2019). Analysis of suffusion in cohesionless soils with randomly distributed porosity and fines content. Comput. Geotech., 111: 157-171.
  • Yang J#, Yin Z-Y, Laouafa F, Hicher P-Y(2019). Internal erosion in dike-on-foundation modeled by a coupled hydro-mechanical approach. Int. J. Numer. Anal. Methods Geomech., 43(3): 663-683.