Experimental Study of Factors Controlling Instability of Frictional Materials.

Abstract

The objectives of the experimental investigations being reported here were to further study the factors that control the stability and instability of frictional materials. The study is divided into two parts: (1) Conditions for Instability, in which a coarse sand was tested at a total of three void ratios to study effects of density as well as additional aspects of instability of granular materials. These experiments were conducted in high pressure triaxial equipment (cell pressures up to 70 MPa). (2) Creep in Sand, in which a fundamental study of creep and relaxation of granular materials was performed, because time-dependent behavior has considerable influence on the stability of granular materials. The sand employed in the experiments had weak, easily crushed grains, which typically exhibit considerable creep. The experiments were performed under drained conditions in order to maintain a constant stress state. Various stress states were used to study whether the plastic potential can be used for prediction of the relative magnitudes of the inelastic creep strain increments, and to examine the effect of creep on the outward movement of the plastic yield surface. This in turn will control the conditions for instability.

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Document Details

Document Type
Technical Report
Publication Date
Mar 01, 1997
Accession Number
ADA325550

Entities

People

  • Poul V. Lade

Organizations

  • Johns Hopkins University

Tags

Communities of Interest

  • Air Platforms
  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Back Pressure
  • Civil Engineering
  • Control Systems
  • Creep Tests
  • Engineering
  • Engineers
  • Geotechnical Engineering
  • Granular Materials
  • High Pressure
  • Materials
  • Measurement
  • Mechanical Equipment
  • Mechanics
  • Plastic Deformation
  • Pore Pressure
  • Soil Mechanics
  • Stress Strain Relations

Readers

  • Geotechnical Engineering.
  • Mechanical Engineering/Mechanics of Materials.
  • Plasma Physics / Magnetohydrodynamics