A Fracture Mechanics and Crack Propagation Approach to the Study of Overconsolidated Clays.
Abstract
Fracture and crack propagation is over consolidated clays have been part of geotechnical engineering thinking for years. The mechanical behavior of stiff clays is studied and analyzed through the discipline of fracture mechanics. A test is developed to determine the critical stress intensity factor, KIC, for the opening mode. The specimen with the configuration of a hollow disk and a notch cut in its internal surface is fatigued under cyclic internal pressure, then failed to determine the pattern of crack propagation. The critical length of the crack is used to determine KIC for various degrees of over consolidation. While consolidation leads to an increase in strength, it resulted in a noticeable decrease in the value of KIC. A second test was developed to determine the critical stress intensity factor KIIC for the shearing mode. This is the first time a non-ambiguous mode II fracture has been obtained for any material. The specimen with the configuration of a thin long hollow cylinder with a notch cut into it, is subjected to hydrostatic pressure and pure torsion. The influence of over consolidation on KIIC was much smaller than that observed on KIC. KIC and KIIC characterize catastrophic failure and do not describe the phenomenon of slow crack propagation. The kinetics of crack propagation for mode I was studied by direct surface observation, compared to crack lengths calculated from crack opening displacement observations. Originator supplied keywords include: Fracture; Over consolidated clay; Stress intensity factors; Crack propagation; Damage zone; Irreversible thermodynamics; Kinetics; Stability; and Soil mechanics.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1985
- Accession Number
- ADA153066
Entities
People
- A. Chudnovsky
- A. S. Saada
- M. Sharaf
- Marian Kennedy