A preliminary examination of the thixotropy of some sedimentary rocks

Boswell, P. G. H.

doi:10.1144/gsl.jgs.1948.104.01-04.23

Cited by 38 publications

(12 citation statements)

References 14 publications

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“…The upper subsoil layer is a decomposed granite soil called "Masado," which is a sandy soil with much gravel, silt, and clay, and the contents of gravel and fines are ϳ0%-65% and 5%-35%, respectively (Yasuda et al, 1996). According to many researchers, the presence in soil of even a small quantity of clay particles (1.5%-2% by Gumensky, 1965) imparts thixotropic properties to the soil (Boswell, 1949;Akkerman, 1958;Gumensky, 1965). Soils like Masado, which contain small quantities of fines, possess intermediate properties between noncohesive and cohesive (quasi-thixotropic) soils.…”

Section: Pi Sitementioning

confidence: 99%

Changes in Shear Moduli of Liquefied and Nonliquefied Soils during the 1995 Kobe Earthquake and Its Aftershocks at Three Vertical-Array Sites

Павленко¹

2002

Bulletin of the Seismological Society of America

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Acceleration records of the 1995 Kobe earthquake and its first aftershocks, provided by vertical arrays at Port Island (PI), SGK, and TKS sites, were used to estimate changes in the shear moduli of subsurface soils caused by strong ground motion. Shear-moduli estimates are based on stress-strain relations determined for consecutive time intervals during the mainshock and aftershocks. We found that in the upper 0-13 m at PI (reclaimed fill above the groundwater level), the shear modulus decreased by ϳ80%-90% of its initial value owing to liquefaction. Signs of its recovery appeared 3-5 min after the decrease in the intensity of strong motion. At depths of 13-18 m (reclaimed fill below the water level) and 27-32.5 m (water-saturated sand) at PI, 0-11 m at SGK, and 0-14 m at TKS (water-saturated alluvium), the shear modulus decrease was estimated at about ϳ80%, 50%-60%, 60%-70%, and ϳ50%, respectively. Recovery began immediately after the decrease in the intensity of strong motion and was completed within a few minutes. The results show that the behavior of the upper layers at sites PI and SGK, where the highest accelerations were recorded, was dynamically unstable. So far as the method can be applied to any site where vertical-array records and profiling data are available, accumulation of representative data on nonlinear soil behavior during strong motion for various soil conditions is desirable. Summarizing and generalizing these data, we may be able to predict soil behavior in future earthquakes.

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Section: Pi Sitementioning

confidence: 99%

Changes in Shear Moduli of Liquefied and Nonliquefied Soils during the 1995 Kobe Earthquake and Its Aftershocks at Three Vertical-Array Sites

Павленко¹

2002

Bulletin of the Seismological Society of America

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“…Although the exact cause of viscosity variations in natural systems is debated, it is broadly accepted that their rheological behaviour is controlled by competition between (1) the break-down of particle-particle interactions and microstructures in the fluid under flow stresses, and (2) the build-up of new interactions and microstructures promoted by van der Waals and electrostatic attractive forces, in-flow collisions and Brownian motion (e.g. Boswell, 1948;Barnes, 1997;Mewis and Wagner, 2009). These interactions are controlled by numerous parameters, including those listed below.…”

Section: The Cause Of Shear Thinning and Thixotropic Behaviourmentioning

confidence: 99%

The rheological behavior of fracture-filling cherts: example of Barite Valley dikes, Barberton Greenstone Belt, South Africa

Ledevin¹,

Arndt²,

Simionovici³

2014

Preprint

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Abstract. A 100 m-thick complex of near-vertical carbonaceous chert dikes marks the transition from the Mendon to Mapepe Formations (3260 Ma) in the Barberton Greenstone Belt, South Africa. Fracturing was intense in this area, as shown by the profusion and width of the dikes (ca. 1 m on average) and by the abundance of completely shattered rocks. The dike-and-sill organization of the fracture network and the upward narrowing of some of the large veins indicate that at least part of the fluid originated at depth and migrated upward in this hydrothermal plumbing system. Abundant angular fragments of silicified country rock are suspended and uniformly distributed within the larger dikes. Jigsaw-fit structures and confined bursting textures indicate that hydraulic fracturing was at the origin of the veins. The confinement of the dike system beneath an impact spherule bed suggests that the hydrothermal circulations were triggered by the impact and located at the external margin of a large crater. From the geometry of the dikes and the petrography of the cherts, we infer that the fluid that invaded the fractures was thixotropic. On one hand, the injection of black chert into extremely fine fractures is evidence for low viscosity at the time of injection; on the other hand, the lack of closure of larger veins and the suspension of large fragments in a chert matrix provide evidence of high viscosity soon thereafter. The inference is that the viscosity of the injected fluid increased from low to high as the fluid velocity decreased. Such rheological behavior is characteristic of media composed of solid and colloidal particles suspended in a liquid. The presence of abundant clay-sized, rounded particles of silica, carbonaceous matter and clay minerals, the high proportion of siliceous matrix and the capacity of colloidal silica to form cohesive 3-D networks through gelation, account for the viscosity increase and thixotropic behavior of the fluid that filled the veins. Stirring and shearing of the siliceous mush as it was injected imparted a low viscosity by decreasing internal particle interactions; then, as the flow rate declined, the fluid became highly viscous as the inter-particulate bonds (siloxane bonds, Si-O-Si) were reconstituted. The gelation of the chert was rapid and the structure persisted at low temperature (T < 200 °C) before fractures were sealed and chert indurated.

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“…This kind of phenomenon needs careful investigation because the developed textures and structures reflect the conditions of deposition of the sediments, and local differences in behavior of different elements of the sand-clay complex (Boswell, 1949) imply differences in the local physieo-chemieal environment of the deposits.…”

Section: Structural Attitudementioning

confidence: 99%

Guide to Field Trip of Fourth National Clay Conference: Clay Minerals in Sedimentary Rocks

Griffiths

1955

Clays clay miner. (Natl. Conf. Clays Clay Miner.)

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A preliminary examination of the thixotropy of some sedimentary rocks

Cited by 38 publications

References 14 publications

Changes in Shear Moduli of Liquefied and Nonliquefied Soils during the 1995 Kobe Earthquake and Its Aftershocks at Three Vertical-Array Sites

Changes in Shear Moduli of Liquefied and Nonliquefied Soils during the 1995 Kobe Earthquake and Its Aftershocks at Three Vertical-Array Sites

The rheological behavior of fracture-filling cherts: example of Barite Valley dikes, Barberton Greenstone Belt, South Africa

Guide to Field Trip of Fourth National Clay Conference: Clay Minerals in Sedimentary Rocks

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