Micromechanics and Constitutive Modeling of Granular Materials in Stress Reversal and Cyclic Loading.
Abstract
The work performed under this grant, focused on fundamental research on cyclic response and response in unloading and stress reversal regimes of granular materials. The research program included a careful examination of grain-to-grain interaction during load reversal, which results in a dramatic change in the overall response of granular materials, from loading to unloading. This was then followed by a fundamental examination of the cyclic response of granular materials under confinement, with repeated stress reversals. Parallel with the theoretical work, the research program included a series of coordinated experiments using UCSD's special large hollow cylindrical load cell and the biaxial and simple shearing load frames with photoelastic granules. These experiments served several specific purposes: (1) appropriately incorporating lead shot in the large hollow cylindrical sample, a series of X-ray photographs were taken to identify the micromechanical response during load reversal; (2) densification and/or dilatancy measurements in load reversal and cyclic loading provided guidance for the theoretical work; (3) by direct observations, using the biaxial and simple shearing facilities, micromechanical changes in unloading, load reversal, and cyclic loading were examined with the ald of photoelastic granules; and (4) controlled independent experiments were used to validate the resulting models, and to evaluate the key parameters. (MM)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 12, 1995
- Accession Number
- ADA297858
Entities
People
- S. Nemat-nasser
Organizations
- University of California, San Diego