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Anteneh Biru Tsegaye

Publications and source records attributed to Anteneh Biru Tsegaye.

3 recordsLinked to original sources
arXiv2023

Novel theoretical considerations of the coefficient of earth pressure at rest

One of the well-known and widely applied parameters in soil mechanics is the so-called coefficient of earth pressure at rest (denoted by a K0). Field and laboratory investigations show that this parameter is correlated with the friction angle and the overconsolidation ratio of the soil deposit. For normally consolidated clays, the expression developed by Jaky is considered to hold good. The extension of Jaky's equation for overconsolidated soils is built mainly on empirical observations; and there is lack of a theoretical framework that satisfactorily explains the relationship. In this paper, these relationships are investigated from the nature of energy dissipation of soil aggregates. For the same, the cyclic stress-dilatancy relationship proposed by the author is employed. Then, the stress ratio that maximizes entropy is derived; and this stress ratio is shown to be reasonably close to the coefficient earth pressure ratio proposed by Jaky. An exponential relationship between K0 and OCR is derived; and for a special case, the exponent is shown to be the sine of the critical state friction angle. Finally, some generalizations are given and aspects which need further investigation are highlighted.

physics.geo-ph↗
arXiv2021

Cyclic stress-dilatancy relations and associated flow for soils based on hypothesis of complementarity of stress-dilatancy conjugates

Applicability of associated plasticity for particulate materials such as soils does not yield satisfactory results when Coulomb's theory of shear strength of soils is assumed, and the yield function derived accordingly is used to define both the stress state and the direction of plastic flow. The limitation mainly stems from the fact that Coulomb's theory (and its derivatives) is a simplification that intentionally ignores deformation characteristics that manifest from the particulate nature of such materials. It is thus customary to apply a branch of plasticity called non-associated plasticity for soils and similar materials. In the non-associated plasticity framework, yield functions and plastic potential functions are different. The former defines the mobilization of the stress state while the later defines the direction of plastic flow. For soils, stress-dilatancy theories have become central in the formulation of non-associated flow rules. In this paper, cyclic stress-dilatancy relations are derived based on complementarity hypothesis of stress-dilatancy conjugates. Both loading and unloading are explicitly considered. Then, yield functions are derived based on the resulting stress-dilatancy relations. In so doing, the resulting yield functions are rendered with a quality to be used for the modelling of deformation behavior of soils subjected to monotonic and cyclic loading conditions. The newly derived yield functions are called Associated Cyclic Stress Dilatancy yield functions for which the abbreviation ACStD is used. The theoretical framework is established first for special cases of deformation modes-plane strain and axisymmetric. The framework is generalized for considering Lode angle dependency of the yield function and extending the Matusoka-Nakai criterion.

physics.app-ph↗