Consideration on Characteristics and Recognition Theories of Soils

Author gives out his views of point on some fundamental concepts commonly used in soil mechanics based on author' s understanding. Discussed properties of soils include: ELAS- T1CITY and PLASTICITY, discussion is focused on how different definitions of elasticity have the effect on theory verification. HOMOGENEITY and MICROSTRUCTURE. Pore motion and evolution and the sublayer of microstructures, which consists of heterogeneity, is the essence of intricate mechanical behaviors of soils. MACRO-FIELD and MICROFIELD. The first is how to express micro-field complextely ,fractal may be a useful tool. The second is how to connect the complex index with macroscopic mechanical behaviors. A method is suggested which considers energy dissipation mechanism in microscopic scale. DILATANCY and DEVIATORIC PLASTICITY. A definite relation is verified by many experimental data. Author derived out it from a micromechanical model. Discussed recognition theories include two:RELATIONSHIP BETWEEN DRUCKER POSTULATE, I-LYUSHIN POSTULATE and IRREVERSIBLE THERMODYNAMICS. The postulates are the direct sequence of entropy inequality, expressing complementary energy (Drucker) and free energy (I-Ivushin) reach maximum and minimum respectively,and are unnecessary for plasticity. So it is impossible to describe total behaviors of soils based on them. MACRO / MICRO COMBINATION THEORIES. A simplified micromechanics method, whose material functions and constants determined by macroscopic test data,makes micromechanics applicable in engineering. Other problems are also discussed in this paper.

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TU43