lithostatic pressure

lithostatic pressure

[¦lith·ə¦stad·ik ′presh·ər]
(geophysics)
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The vertical stress (ov) is the magnitude of the lithostatic pressure (equation 1) exerted on a point at a depth of "z" by the material on top of it with a density of "p" and the acceleration of gravity ([gamma]).
The combined effect of the lithostatic pressure ([[sigma].
Even the stable salt access roads are under high lithostatic pressure, because of the depth of the workings, and long horizontal slots are cut into the sides of the roadways to relieve stress.
To cope with greater lithostatic pressures in the ore at depths below 1,200 meters and to raise the production level above 3 million tons of ore per year by 2001, CPL converted its continuous miners to a remote-controlled operation, so they can be safely used in shaly sections without prior blasting.
The big finding is that there is very high fluid pressure down there, that is, lithostatic pressure, which means pressure equivalent to the load of all rock above it, 15 to 30 kilometers (10 to 20 miles) of rock," Nadeau said.
An average rhyolitic magma undersaturated in water remains under lithostatic pressure until saturation is reached.
The exsolution of the excess volatile phase continues as the magma chamber decompresses toward lithostatic pressure.
Test results reveal: 1) maximum water table height and pore-water pressure occur when the sand column is approximately twice the initial water table height, 2) pore-water pressure remains high long after the shaking ceases, apparently due to the elevated water table, 3) with an impermeable layer the pore-water pressure continues to rise as the sand height increases, 4) with an impermeable layer pore-water pressure remains high long after the shaking ceases, apparently due to the lithostatic pressure of the sand column above the impermeable layer, 5 ) sand compaction occurs beneath the water table, and 6) the amount of sand compaction is controlled by initial water table height.
These veins are formed by extensional opening of a fracture when fluid pressures within the shear zone exceeded the lithostatic pressure imposed by the overlying rocks.
Since all deposited transuranic waste must be retrievable during the initial five-year operating period, the boreholes have steel sleeves that withstand salt lithostatic pressure to ease retrieval.
During extraction of samples from great depths and their release from lithostatic pressure, many microfractures are formed at grain boundaries and inside grains.
The general tendency for the density decrease observed on the plot, Figure 1, can be explained by the samples decompaction during their extraction from a great depth and lithostatic pressures and temperature release (Gorbatsevich, 2003).