Delayed failure of a deep cutting in lodgement till

Recent research on the delayed failure of cuttings in clay clearly recognises and predicts progressive delayed failure of deep cuttings. This is due to a combination of strain-softening, weathering, dissipation of negative excess pore water pressure generated at the time of excavation, and frequent occurrence of prolonged periods of wet weather. There have been several slope failures of this kind in Northern Ireland. This paper discusses a case study based on a failure of a deep cutting, excavated at a slope of 1 in 2, on the A1 near Dromore (County Down) in Northern Ireland. The cutting was in lodgement till, a stiff, heavily overconsolidated clay. The failure occurred approximately 30 years after the cutting was excavated, following a prolonged period of heavy rainfall. An analysis of the failure, together with laboratory test data on soil samples taken from the site, confirmed that by using long-term soil strength parameters the factor of safety of this slope was unity. The conclusion of the analysis is that slopes excavated in this soil should be designed (and assessed) on long-term strength parameters.

Failure of Local Realism Revealed by Extremely-Coarse-Grained Measurements

We show that failure of local realism can be revealed to observers for whom only extremely-coarse-grained measurements are available. In our instances, Bell's inequality is violated even up to the maximum limit while both the local measurements and the initial local states under scrutiny approach the classical limit. Furthermore, we can observe failure of local realism when an inequality enforced by nonlocal realistic theories is satisfied. This suggests that locality alone may be violated while realism cannot be excluded for specific observables and states. Small-scale experimental demonstration of our examples may be possible in the foreseeable future.

Scaling in the time-dependent failure of a fiber bundle with local load sharing

We study the scaling behaviors of a time-dependent fiber-bundle model with local load sharing. Upon approaching the complete failure of the bundle, the breaking rate of fibers diverges according to r(t)proportional to(T-f-t)(-xi) where T-f is the lifetime of the bundle and xi approximate to 1.0 is a universal scaling exponent. The average lifetime of the bundle [T-f] scales with the system size as N-delta, where delta depends on the distribution of individual fiber as well as the breakdown rule. [S1063-651X(99)13902-3].

Failure of fiber bundles with local load sharing

We develop a recursion-relation approach for calculating the failure probabilities of a fiber bundle with local load sharing. This recursion relation is exact, so it provides a way to test the validity of the various approximate methods. Applying the exact calculation to uniform and Weibull threshold distributions, we find that the most probable failure load coincides with the average strength as the size of the system N --> infinity.