Micromechanical modelling of cemented sands under low amplitude oscillations

Abstract

Microstructural continuum modelling is applied to study the mechanical properties of cemented sands under low amplitude oscillatory loading. The effect of cement in sand is accounted for by considering adhesion in addition to friction at the inter-particle contact. Under the assumption that cemented sands are statistically isotropic random packings of equal spheres, a closed form relationship is derived for the initial shear modulus of cemented sands under isotropic confining stress. Also, the secant moduli and damping ratios are computed numerically for various strain amplitudes. The influence of degree of cementation, initial confining stress, particle size, void ratio and strain amplitude on the mechanical properties of cemented sands are investigated. Comparisons of the theoretically predicted results are made with experimental measurements.

Development of correlations for soil thermal conductivity

“…As shown in Figure 7, the relationship between dry density and thermal conductivity is linear at a given level of saturation. As shown in Figure 8, when the dry density increases, the number of contact points between the soil particles increases [14]. This increase in contact points results in an increase in the effective heat flow area which causes an increase in soil thermal conductivity.…”

On incremental non-linearity in granular media: phenomenological and multi-scale views (Part I)

“…Many studies [53][54][55] have attempted to relate the mean number of contacts per grain in a cohesionless granular assembly in terms of internal variables such as compactness. To exemplify this, the empirical relation proposed by Field [53] can be adopted:…”

On a multilaminate model for soil incorporating small strain stiffness

“…the number of contacts made by a sphere with neighbouring spheres is 6 for the simple cubic packing and 12 for the hexagonal packing. For real granular material having particles of various sizes, Chang et al [30] proposed the following relationship between void ratio (e), the average co-ordination number (C n ) and the mean particle size:…”

“…Yanagisawa [36] also presented experimental data on glass balls and gravel with two different particle shapes. For the application within the MMS, a simple linear relation is adopted as proposed by Chang et al [30]. They provide an approximation of the co-ordination number and the void ratio for the range of 0.38 e 0.87 based on their studies C n = 13.28−8e (14) Figure 3 shows the experimental data of different gravels and results for systematic assemblies of equal-sized spheres together with a plot of Equation (14).…”