foundation system of burj al arab

Properties of Aeolian Soil, Loess (Part-2)

Dear reader we were discussing about properties of loess soil. These deposits have loose structure which is abundant with root holes. These produce vertical cleavage in these deposits which effects permeability.

Here we are listing physical properties of loess:

a. Homogeneous

b. Porous

c. Crumble

d. Color may be brownish or pale yellow

e. Generally not stratified

f. Often calcareous; means partly or mostly consists of CaCO3(calcium carbonate)

Capillaries in loess soil
The grain sizes have already been described in previous part, regarding shape of grains; they are angular and composed mainly of minerals in crystal form like

a. Quartz

b. Feldspar

c. Mica

d. Other materials

Though angular in shape a little rounding or polishing is observed.

Hilf and Holtz(1961) recommended that moisture content at saturation of that loessial soils exceed liquid limit, should be carefully investigated as they have susceptibility to collapse. This phenomenon is possible when void ratio is adequately large.

So to have collapse,

WSaturated  ≥ LL

Capillaries traverse vertically in loess soil, as discussed earlier, which allow deposits to fracture and results vertical bluffs. Thus permeability in horizontal direction is much smaller than that in vertical direction.

Dear reader index properties of loess soils will be discussed in next post and in upcoming posts we will discuss foundation problems under loess soil and calculation method for collapse settlement.

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