Preconsolidating

Posted by / 02-Sep-2017 12:44

Preconsolidating

It is important to know the preconsolidation pressure because it will help to determine the amount of loading that is appropriate for the site.

by Leo Casagrande, Serial Information: Journal of the Soil Mechanics and Foundations Division, 1964, Vol. 349-365Document Type: Journal Paper Abstract: By a theoretical investigation and by settlement analysis and observations on a large oil tank, it is shown that the ratio between the settlements along the periphery and in the center of a uniformly loaded area can vary within a wide range, depending on the degree of preconsolidation of the subsoil.

as the intersection of two lines: (a) the regression line obtained for the first two, three, four or five points of the applied stress sequence in the secondary compression portion of the compression curve and (b) the extension of the virgin compression line determined from the points associated with applied stress of 8 k Pa. The σ estimated using the graphical procedure of Casagrande for 288 soil compression curves from three soils in Michigan and from values reported in the literature.

Methods 1 and 5 fit our data best at low σ (0.92), and closeness of fit to the 1:1 line, a combination of methods 1 and 3 was selected as the best estimation procedure.

For example, in samples with natural moisture content at the liquid limit (liquidity index of 1), preconsolidation ranges between about 0.1 and 0.8 tsf, depending on soil sensitivity (defined as the ratio of undisturbed peak undrained shear strength to totally remolded undrained shear strength). used this method to calculate the preconsolidation pressure of 139 undisturbed soil samples to generate preconsolidation pressure maps of the Vega Baja of the Segura (Spain).

proposed an analytical method to calculate preconsolidation stress that avoids subjective interpretations of the location of the maximum curvature point (i.e. Using a consolidation curve, intersect the horizontal portion of the recompression curve and a line tangent to the compression curve.

For normally consolidated clay, this ratio normally ranges between 0.6 and 0.7, and for extremely sensitive, overconsolidated clay, it may be as small as 0.1, or even smaller.

It is useful to know the range of expected values depending on the type of soil being analyzed.All of these require site evaluation before construction.Preparing a site for construction requires an initial compression of the soil to prepare for foundation to be added.In a water-jet needling method for preconsolidating a nap (F) of fibers and/or filaments transported on a substrate (2), the water jet needling device (3) is positioned at a large spacing (a) from the substrate.An independent claim is included for apparatus for preconsolidating the nap (F) of fibers...

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Methods to identify the parameters of the model from oedometer tests are described.