Experimental studies relating to microfracture in sandstone

Gallagher, John J.; Friedman, M.; Handin, John; Sowers, G.M.

doi:10.1016/0040-1951(74)90053-5

Cited by 243 publications

(35 citation statements)

References 21 publications

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“…3c). These features are consistent with Hertzian-type stressing in unconsolidated porous aggregates (e.g., CHESTER et al, 2004;GALLAGHER et al ,1974). Some mica crystals (''M'' in Fig.…”

Section: Microscale Damage Characteristicssupporting

confidence: 68%

Characterization of Damage in Sandstones along the Mojave Section of the San Andreas Fault: Implications for the Shallow Extent of Damage Generation

Dor

Chester

Ben‐Zion

et al. 2009

Pure appl. geophys.

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Following theoretical calculations that suggest shallow generation of rock damage during an earthquake rupture, we measure the degree of fracture damage in young sedimentary rocks from the Juniper Hills Formation (JHF) that were displaced 21 km along the Mojave section of San Andreas Fault (SAF) and were not exhumed significantly during their displacement. In exposures adjacent to the fault, the JHF typically displays original sedimentary fabrics and little evidence of bulk shear strain at the mesoscopic scale. The formation is, however, pervasively fractured at the microscopic scale over a zone that is about a 100 m wide on the southwest side of the SAF near Little Rock. The abundance of open fractures, the poor consolidation, and the shallow inferred burial depth imply that the damage was generated close to the surface of the Earth. The spatial correlation of this damage with a seismically active trace of the SAF suggests that it was generated by SAF slip events that by assumption were of a seismic nature throughout the displacement history of the JHF. Thus the JHF provides a very shallow upper bound for the generation of brittle damage in a seismic fault zone. The fracture fabric is characterized by preferred orientations of fractures that split grains between contact points and is consistent with overall deformation under directed compression. However, the available results cannot be used to distinguish between proposed off-fault damage mechanisms. Fracture orientations are compatible with a maximum compressive stress oriented at a high angle to the fault at about 10 m, and at a lower, more variable angle farther away from the fault. The fracture distribution and fabric are consistent with observations made of the microscale damage characteristics of the Hungry Valley Formation in the northwestern section of the SAF in the Mojave, and with previous observations of exhumed, ancestral strands of the SAF.

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“…3c). These features are consistent with Hertzian-type stressing in unconsolidated porous aggregates (e.g., CHESTER et al, 2004;GALLAGHER et al ,1974). Some mica crystals (''M'' in Fig.…”

Section: Microscale Damage Characteristicssupporting

confidence: 68%

Characterization of Damage in Sandstones along the Mojave Section of the San Andreas Fault: Implications for the Shallow Extent of Damage Generation

Dor

Chester

Ben‐Zion

et al. 2009

Pure appl. geophys.

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“…5d) as a result of stress concentration at the grain-to-grain contact points (e.g. Gallagher et al, 1974). Intense cataclasis and fragmentation within the fault core is supported by grain size distribution data (Figs.…”

Section: Deformation Mechanismsmentioning

confidence: 96%

Grain size and permeability evolution of soft-sediment extensional sub-seismic and seismic fault zones in high-porosity sediments from the Crotone basin, southern Apennines, Italy

Balsamo

Storti

2010

Marine and Petroleum Geology

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“…At the same time, crushing tests conducted on single sand grains show an increase in the load at failure (F c = 30-350 N) with increasing grain size (d = 0.5-6.3 mm) [Gallagher, 1976;McDowell, 2002]. With regard to microscale failure mode, petrographic studies have revealed that the dominant grain failure mechanism leading to aggregate compaction and single-grain crushing is the development of tensile intra and transgranular cracks at grain contacts due to point loading [Bernabe and Brace, 1990;Chester et al, 2004;Chuhan et al, 2002;Gallagher et al, 1974;Gallagher, 1976Gallagher, , 1987Gill et al, 1990;Hangx et al, 2010;Karner et al, 2003;Myer et al, 1992;Wong, 1990;Zhang et al, 1990].…”

Section: Introductionmentioning

confidence: 99%

Failure behavior of single sand grains: Theory versus experiment

et al. 2011

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[1] Grain-scale brittle fracture and grain rearrangement play an important role in controlling the compaction behavior of reservoir rocks during the early stages of burial. Therefore, the understanding of single-grain failure is important. We performed constant displacement rate crushing tests carried out on selected, well-rounded, single sand grains and on randomly sampled grains from different grain size (d) batches of pure quartz sand. Applying a Hertzian fracture mechanics model for grain crushing, the critical load at failure (F c ) data obtained for the selected grains were converted into an accurate estimate of the size of flaws associated with failure (c f ). Similarly, the distributed F c data obtained from the different batch samples were converted into distributions of grain failure stress. Weibull weakest link theory could not explain the observed grain failure behavior. On the contrary, the Hertzian grain failure criterion enabled the conversion of the distributed F c data, for the batch samples, into distributions of c f , assuming spherical grains, or of "effective" radius of curvature (r g ), characterizing contact surface asperities in the case of nonspherical grains. In contrast to the model of Zhang et al. (1990), our work shows that there is no clear physical basis for a grain size dependence of c f . However, since roundness data for dune sands exhibit a similar relation between r g and d, as seen in our grain size batches, it is inferred that the Hertzian fracture mechanics model assuming nonspherical grains with a distributed r g is the most physically reasonable model for grain failure.

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Experimental studies relating to microfracture in sandstone

Cited by 243 publications

References 21 publications

Characterization of Damage in Sandstones along the Mojave Section of the San Andreas Fault: Implications for the Shallow Extent of Damage Generation

Characterization of Damage in Sandstones along the Mojave Section of the San Andreas Fault: Implications for the Shallow Extent of Damage Generation

Grain size and permeability evolution of soft-sediment extensional sub-seismic and seismic fault zones in high-porosity sediments from the Crotone basin, southern Apennines, Italy

Failure behavior of single sand grains: Theory versus experiment

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