Accession Number : ADA325550

Title :   Experimental Study of Factors Controlling Instability of Frictional Materials.

Descriptive Note : Final rept. Nov 93-Oct 96,

Corporate Author : JOHNS HOPKINS UNIV BALTIMORE MD DEPT OF CIVIL ENGINEERING

Personal Author(s) : Lade, Poul V.

PDF Url : ADA325550

Report Date : MAR 1997

Pagination or Media Count : 77

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.

Descriptors :   *STRESS STRAIN RELATIONS, *HIGH PRESSURE, *FRICTION, *INSTABILITY, *GRANULAR MATERIALS, DENSITY, SAND, SURFACES, DRAINAGE, CREEP, PLASTICS, PORE PRESSURE, STRESS RELAXATION, TRIAXIAL STRESSES.

Subject Categories : Civil Engineering
      Construction Equipment, Materials & Supplies

Distribution Statement : APPROVED FOR PUBLIC RELEASE