The equivalent inter-granular void ratio appears to be a pertinent density variable in analysing ... more The equivalent inter-granular void ratio appears to be a pertinent density variable in analysing the mechanical response of silty sand. Using this density variable, the critical state locus (CSL) in the void ratio against mean effective stress plane for soil mixtures with various fines content can be normalised into a narrow band to give a single CSL. The equivalent inter-granular void ratio is defined as a function of fines content and a parameter b. However, the parameter b is vaguely defined as the fraction of active fines, which is considered to be a constant by some researchers and also as a function of fines content by other researchers. Until now, there are no conclusive ways of determining parameter b. In this respect, a new formula of the equivalent inter-granular void ratio is derived from the perspective of a recently proposed particle packing model. The new formula also shows that the parameter b is a function of specific volumes of coarse and fine particles. The two spe...
Microstructural continuum modelling is applied to study the mechanical properties of cemented san... more 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. Un modele à continuum microstructural est utilisé pour étudier les propriétés mécaniques des sables cimentes sous chargement oscillatoire d...
Vertical and Horizontal Deformations of Foundations and Embankments, 1994
Empirical equations for one dimensional compression of sand do not include parameters characteriz... more Empirical equations for one dimensional compression of sand do not include parameters characterizing properties of sand grains (e.g. moduli, size and shape of sand grains, and friction properties between grains). In this paper, close-form expressions of compressibility and lateral earth pressure are derived for spherical particles in a body centered arrangement. The predicted results are compared with experimental measurements for sands under both loading and unloading conditions. The effects of micro-scale properties and macro-scale responses are discussed to provide insights for future improvements in abilities of predicting settlement under complicated loading conditions.
This paper gives a review of newly developed probabilistic methods for analysis of the effect of ... more This paper gives a review of newly developed probabilistic methods for analysis of the effect of randomness in geometry and physical properties at the microscale on their macroscale response for granular material. Two problem areas are discussed: 1) characterization of the stochastic geometry for granular material as a collection of particles, and 2) averaging process for obtaining macroscale response.
The equivalent inter-granular void ratio appears to be a pertinent density variable in analysing ... more The equivalent inter-granular void ratio appears to be a pertinent density variable in analysing the mechanical response of silty sand. Using this density variable, the critical state locus (CSL) in the void ratio against mean effective stress plane for soil mixtures with various fines content can be normalised into a narrow band to give a single CSL. The equivalent inter-granular void ratio is defined as a function of fines content and a parameter b. However, the parameter b is vaguely defined as the fraction of active fines, which is considered to be a constant by some researchers and also as a function of fines content by other researchers. Until now, there are no conclusive ways of determining parameter b. In this respect, a new formula of the equivalent inter-granular void ratio is derived from the perspective of a recently proposed particle packing model. The new formula also shows that the parameter b is a function of specific volumes of coarse and fine particles. The two spe...
Microstructural continuum modelling is applied to study the mechanical properties of cemented san... more 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. Un modele à continuum microstructural est utilisé pour étudier les propriétés mécaniques des sables cimentes sous chargement oscillatoire d...
Vertical and Horizontal Deformations of Foundations and Embankments, 1994
Empirical equations for one dimensional compression of sand do not include parameters characteriz... more Empirical equations for one dimensional compression of sand do not include parameters characterizing properties of sand grains (e.g. moduli, size and shape of sand grains, and friction properties between grains). In this paper, close-form expressions of compressibility and lateral earth pressure are derived for spherical particles in a body centered arrangement. The predicted results are compared with experimental measurements for sands under both loading and unloading conditions. The effects of micro-scale properties and macro-scale responses are discussed to provide insights for future improvements in abilities of predicting settlement under complicated loading conditions.
This paper gives a review of newly developed probabilistic methods for analysis of the effect of ... more This paper gives a review of newly developed probabilistic methods for analysis of the effect of randomness in geometry and physical properties at the microscale on their macroscale response for granular material. Two problem areas are discussed: 1) characterization of the stochastic geometry for granular material as a collection of particles, and 2) averaging process for obtaining macroscale response.
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Papers by Ching S. Chang