Stress relief and cliff stability at a power station near niagara falls

Lee, C.F.

doi:10.1016/0013-7952(78)90012-1

Cited by 9 publications

(4 citation statements)

References 3 publications

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“…Figure 9, where these joints increase in abundance with proximity to the Niagara Escarpment. A similar relationship of more densely spaced joints near the escarpment edge has been observed in the Niagara River Gorge [Lee, 1978].…”

Section: Scanline Surveys In the Gasport Quarrysupporting

confidence: 75%

“…This model suggests that a tensile stress must have developed in the Lockport Dolomite near the Niagara Escarpment. Stress measuremenu in the Niagara River Gorge show S, parallel to the escarpment and a minimum horizontal stress (SO, which in many cases is tensile, normal to the escarpment face [Lee, 1978]. The implication here is that tensile stresses are generated upon relaxation of confuting pressure during the southward retreat of the escarpment.…”

Section: Reentrantsmentioning

confidence: 80%

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A case for neotectonic joints along the Niagara Escarpment

Gross¹,

Engelder²

1991

Tectonics

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In a search for proof that some joints on the Appalachian Plateau are neotectonic, orientation data were collected on more than 1800 fractures in exposures of the Lockport Dolomite in western New York and southern Ontario. Of greatest interest was a late-forming ENE joint set present in the central and western portions of the field area. These joints increase in abundance with proximity to the Niagara Escarpment. The shape of the east-west trending Niagara Escarpment is defined by a series of asymmetric reentrants with a strong ENE linear trend, reflecting the bedrock joint pattern. The joints appear to have formed near the Earth's surface in response to low tensile stresses developed in bedrock adjacent to the retreating escarpment. Since the current shape and position of the escarpment were controlled by glacial activity during the last 3 m.y., it is possible that the ENE joints and reentrants are neotectonic features. J" 70 o I-oo •. so 0 ß ß ß ß ß ß ß ß RE-ENTRANTS LONGITUDE (o)

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Section: Scanline Surveys In the Gasport Quarrysupporting

confidence: 75%

Section: Reentrantsmentioning

confidence: 80%

A case for neotectonic joints along the Niagara Escarpment

Gross¹,

Engelder²

1991

Tectonics

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“…The size of the tensile-stress region decreases abruptly as the cliff inclination decreases. Field observations, numerical analysis, and laboratory testing of lithified Paleozoic sedimentary rocks by Lee (1978) and Lee and Lo (1976) confirm the time-dependent nature of the deformation that leads to stress-release fracturing. In those old, strong rocks, the time delay is on the order of years.…”

Section: Analysis and Discussionmentioning

confidence: 65%

Gravitational Failure of Sea Cliffs in Weakly Lithified Sediment

Hampton

2002

Environmental & Engineering Geoscience

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Gravitational failure of sea cliffs eroded into weakly lithified sediment at several sites in California involves episodic stress-release fracturing and cantilevered block falls. The principal variables that influence the gravitational stability are tensional stresses generated during the release of horizontal confining stress and weakening of the sediment with increased saturation levels. Individual failures typically comprise less than a cubic meter of sediment, but large areas of a cliff face can be affected by sustained instability over a period of several days. Typically, only the outer meter or so of sediment is removed during a failure episode. In-place sediment saturation levels vary over time and space, generally being higher during the rainy season but moderate to high year-round. Laboratory direct-shear tests show that sediment cohesion decreases abruptly with increasing saturation level; the decrease is similar for all tested sediment if the cohesion is normalized by the maximum, dry-sediment cohesion. Large failures that extend over most or all of the height of the sea cliff are uncommon, but a few large wedgeshaped failures sometimes occur, as does separation of large blocks at sea cliff-gully intersections.

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“…The technique can be timeconsuming and complex depending on material property homogeneity, the extent to which a mesh has multiple nodes, and changes in boundary conditions. Examples include the study of cliffs near to Niagara Falls, Canada (Lee, 1978), and isolated mountain peaks in Antarctica (Augustinus and Selby, 1990).…”

Section: Introductionmentioning

confidence: 99%

Modelling failure mechanisms to explain rock slope change along the Isle of Purbeck coast, UK

Allison

Kimber

1998

Earth Surf. Process. Landforms

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Results are presented of distinct element computer modelling used to examine rates and mechanisms of change in rock slopes and cliffs, where material intact properties determine process and form but the most significant controls are the joint pattern and cross-joint properties. The modelling approach does not appear to have been used before in a geomorphological context and provides an alternative approach for examining cliff development. Field and laboratory data have been collected for the Portland Limestone outcrop of the Isle of Purbeck, central southern England. The Portland Limestone is a hard, shelly, crystalline sediment of the Upper Jurassic. It has a regular discontinuity pattern throughout the outcrop in Purbeck. While joint orientation remains relatively constant, bedding changes from horizontal to vertical, a consequence of the Purbeck Monocline. There are resulting implications for spatial variations in rock slope evolution. The modelling exercise enhances previous knowledge on rock failure mechanisms and slope development along the Purbeck coast and demonstrates its potential in research where landforms are developed in lithified, jointed rock masses.

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Stress relief and cliff stability at a power station near niagara falls

Cited by 9 publications

References 3 publications

A case for neotectonic joints along the Niagara Escarpment

A case for neotectonic joints along the Niagara Escarpment

Gravitational Failure of Sea Cliffs in Weakly Lithified Sediment

Modelling failure mechanisms to explain rock slope change along the Isle of Purbeck coast, UK

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