Rock Mechanics and Engineering

Jaeger, Christophe

doi:10.1017/cbo9780511735349

Cited by 568 publications

(193 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For example, l % 0.53 mm for coal rock, l % 0.47 mm for sandstone and l % 1.5 mm for granite. For rock-like geomaterials, v is reasonably ranged from 3.0 to 8.0 (see, e.g., Jaeger, 1979). If here j c is assumed to be 4j 0 so that v = 4 and m is assumed to be 0.2, the corresponding shear band widths for coal rock, sandstone and granite are 11.96 mm, 11.6 mm and 33.84 mm, respectively.…”

Section: Internal Length Scale and Shear Band Widthmentioning

confidence: 99%

Shear banding analysis of geomaterials by strain gradient enhanced damage model

Zhao

Sheng

Weiyuan

2005

International Journal of Solids and Structures

View full text Add to dashboard Cite

Shear band localization is investigated by a strain-gradient-enhanced damage model for quasi-brittle geomaterials. This model introduces the strain gradients and their higher-order conjugate stresses into the framework of continuum damage mechanics. The influence of the strain gradients on the constitutive behaviour is taken into account through a generalized damage evolutionary law. A weak-form variational principle is employed to address the additional boundary conditions introduced by the incorporation of the strain gradients and the conjugate higher-order stresses. Damage localization under simple shear condition is analytically investigated by using the theory of discontinuous bifurcation and the concept of the second-order characteristic surface. Analytical solutions for the distributions of strain rates and strain gradient rates, as well as the band width of localised damage are found. Numerical analysis demonstrates the shear band width is proportionally related to the internal length scale through a coefficient function of PoissonÕs ratio and a parameter representing the shape of uniaxial stress-strain curve. It is also shown that the obtained distributions of strains and strain gradients are well in accordance with the underlying assumptions for the second-order discontinuous shear band boundary and the weak discontinuous bifurcation theory.

show abstract

Section: Internal Length Scale and Shear Band Widthmentioning

confidence: 99%

Shear banding analysis of geomaterials by strain gradient enhanced damage model

Zhao

Sheng

Weiyuan

2005

International Journal of Solids and Structures

View full text Add to dashboard Cite

show abstract

“…where ρ is material density of impactor, K RQD is rock quality in % (Jaeger [24]). Table 7 shows the relationship between K RQD and rock quality (Deere [25]).…”

Section: Bernard Model (1977)mentioning

confidence: 99%

Engineering models of high speed penetration into geological shields

2014

View full text Add to dashboard Cite

Abstract:The survey is dedicated to approximate empirical and analytical models which were suggested for describing high-speed penetration into geological shields. This review differs from the previously published reviews on this topic in the following respects: (i) includes a large number of models; (ii) describes models suggested during recent years; (iii) much attention is given to models which have been originally published in Russian and are not well known in the West. References list includes 81 items.

show abstract

“…Gravitationally induced slides, however, invariably seem to be marked with precursors that may precede failure by months, even years. The literature is replete with records of noticeable movement or developing cracks long before the final catastrophic slip, and theories have been developed on the assumption that there are two phases to this type of slide, a 'visco-plastic' first phase of creep and the last phase of sudden, brittle fracture (Jaeger, 1979). Slip creep had been noted in the Aberfan tip years before it failed disastrously.…”

Section: The North Slope Failure Induced By Explosion At Depthmentioning

confidence: 99%

“…The relationship between S, C, o, and ~0 can be determined from a Mohr's circle analysis (see, for instance, Terzaghi and Peck, 1967). Gravitationally induced failures are progressive which causes C to tend to zero (Jaeger, 1979). Setting F = 1 defines a critical slope/3 c = ~0.…”

Section: The North Slope Failure Induced By Explosion At Depthmentioning

confidence: 99%

The mechanism of the Mt. St. Helens eruption and speculations regarding Soret effects in planetary dynamics

Rice

1985

Geophysical Surveys

View full text Add to dashboard Cite

Abstract. Steady heat flux through a double diffusive layered convecting system demands each layer have the same Rayleigh number. If double diffusive convective layering occurs in a gaseous rotating proto-solar system nebula of uniform composition, this Rayleigh number criterion sets the distances from the centre of the nebula to each boundary layer of the convecting layers and these distances are given by the Titius-Bode law. In a layer of nebula convection, outgoing plumes will he retrograde, ingoing plumes prograde, such that where these plumes impinge on a boundary layer, vortices can be set up in the boundary layer with rotation along the same axis as the total cloud. Soret convection may serve to segregate the cloud isotopically, elementally and chemically.With regard to the failure of the north slope on Mt. St. Helens, 18th May, 1980, civil engineering criteria rule out gravitational failure and leave ambiguous the possibility the slide was seismically induced. P arrival and S wave magnitudes from the 18th May eruption along with characteristics of blasting excavation indicates the north slope failure to have been induced by explosion at depth. A review of industrial experience with steam explosions indicates it unlikely the Mt. St. Helens blast was the result of loss of overburden and vapor flashing. Quench cooling, however, may yield vapor super-saturations to 104 atmospheres. Once exsolution was initiated, vapor mass transport would be massive and strip the melt dry of other volatiles, this based on explosive exsolution experience in steel making industries.Further appeal to industrial solidifying melt literature indicates marginal border groups and cryptic variation to be analogs of microsegregation (solute banding) and macrosegregation. Fractional crystallization in the sense of micro and macrosegregation sets up the zonation in a mafic magma chamber necessary to establish double diffusive convective layering and attendent Soret segregation of minerals. Theoretically, rollover, i.e. homogenization of stratified or zoned chambers can occur in marie or andesitic environments. In the andesitic environment, zonation of the chamber from silicic to marie melt with depth indicates that the mafic portions could be explosively supercharged with vapor during the quench attending rollover, i.e., it would 'pop' like popcorn but on a more impressive scale.KNO 3 and NaNO 3 aqueous solutions have negative Soret coefficients which explain peculiar density build-ups in the bottom of experimental tanks. These experiments were designed to model magma chambers but they do not replicate solidifying melts because they lack dynamic similitude: pertinent dimensionless parameters differ by up to 7 orders of magnitude. Scaling crystal size in these experiments indicates that crystals a kilometer across should be found in magma chambers. These experiments also advance a mechanism for picritic intrusions in oceanic crust for which horizontal layering is required. However, ophiolites show essentially arcuate banding and picrites ...

show abstract

Rock Mechanics and Engineering

Cited by 568 publications

References 0 publications

Shear banding analysis of geomaterials by strain gradient enhanced damage model

Shear banding analysis of geomaterials by strain gradient enhanced damage model

Engineering models of high speed penetration into geological shields

The mechanism of the Mt. St. Helens eruption and speculations regarding Soret effects in planetary dynamics

Contact Info

Product

Resources

About