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Used to determine rate of settlement Casagrande & Fadum (1940): Log time

method Taylor (1942): Root time method

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1. Project the straight portions of primary consolidation and secondary compression to intersect at A

2. A is d100 displacement at 100% primary consolidation

3. Select t1, point B, near the initial portion of the parabola. Select t2, point C, such t2 = 4t1

4. Δd = d2 – d1, plot D at distance Δd from B

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5. Calculate d50 = (d0 + d100)/2. Draw horizontal line from this point to intersect the curve at E. The abscissa of point E is the time for 50% consolidation, t50

6. Calculate Cv

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1. Plot the displacement versus square root of times

2. Draw straight line through the initial part of the curve intersecting the ordinate at O and the abscissa (square root of times) at A

3. Note the time at A: √tA4. Locate point B: 1.15 √tA5. Draw OB6. The intersection of OB and the curve is t90

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End of Presentation

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