Sand is supported on a porous disc and screen in vertical cylinder, as shown in Fig. P7.14. These are equilibrium conditions.

(a) For each of the five cases, plot the total, neutral, and effective stresses versus height. These plots should be approximately to scale.

(b) Derive formulas for those three stresses in terms of the dimensions shown and e, ?s, and pw for each case at both the top and bottom of the sand layer. For case IV, assume the sand is 100% saturated to the upper surface by capillarity. For case V, assume the sand above level hc is completely dry and below is completely saturated. (After A. Casagrande)

Transcribed Image Text:

Sand Sand Sand Case I Case Il Case II S= 0% Sand S = 100% Case IV. Assume that the sand is fine enough to remain 100% saturated up to its top surface by capillarity. Case V. Assume an idealized case in which the height of capillary rises he. All soil below that height is 100% saturated, and all soil above that height is O% saturated.