Accession Number : ADA182771

Title :   Flow and Failure of Rocks, Concrete and Other Geomaterials.

Descriptive Note : Final scientific rept. 1 Oct 85-30 Sep 86,

Corporate Author : CALIFORNIA UNIV SAN DIEGO LA JOLLA DEPT OF APPLIED MECHANICS AND ENGINEERING SCIENCES

Personal Author(s) : Nemat-Nasser,S

PDF Url : ADA182771

Report Date : Nov 1986

Pagination or Media Count : 185

Abstract : This research aimed at experimental and theoretical investigation of the micromechanics of flow and failure of rocks, concrete, and other related geomaterials at moderate to very high pressures and temperatures. Macroscopic nonlinear constitutive models have been developed, which reflect realistically the micromechanical events that produce observed macroscopic nonlinear and anisotropic responses of materials of this kind. The theoretical work included calculations of microcrack initiation under overall compression, interaction between cracks, development of plastic of plastic zones and their interaction with cracks, and the final failure mode of, say, rocks. Attention was focused on the influence of the pressure and temperature on the failure mode and on the transition from brittle to ductile response. Modeling of observed axial splitting and faulting at moderate pressures and low temperature was completed, and through some theoretical and model experiments, a basic understanding has been gained for the phenomenon of brittle-ductile transition at elevated pressures. The experimental effort consisted of two parts: (1) qualitative model studies in order to identify and understand the involved micromechanics; and (2) quantitative model tests. Keywords: Rock mechanics; Mechanical properties of concrete.

Descriptors :   *MICROCRACKING, *FAILURE(MECHANICS), *CONCRETE, *ROCK MECHANICS, ANISOTROPY, BRITTLENESS, COMPUTATIONS, CRACKS, DUCTILE BRITTLE TRANSITION, DUCTILITY, HIGH PRESSURE, LOW TEMPERATURE, MECHANICAL PROPERTIES, MECHANICS, MODEL TESTS, NONLINEAR SYSTEMS, PLASTICS, PRESSURE, RESPONSE, ROCK, SPLITTING, THEORY, HIGH TEMPERATURE, COMPRESSIVE PROPERTIES, PLASTIC PROPERTIES

Subject Categories : Geology, Geochemistry and Mineralogy
      Construction Equipment, Materials & Supplies
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE