Homework%2019%20-2009

Homework%2019%20-2009 - The soil deposit consists of 15...

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The University of Missouri-Columbia Department of Civil Engineering Assigned: Monday 12/07/09 Due: NOT TO BE TURNED IN CE 3400 - Homework No. 19 Shear Strength of Clay 1. An unconsolidated-undrained triaxial compression test was performed on a 2.80-in diameter specimen of saturated clay. A confining (cell) pressure of 20 psi was used. At failure, the load applied through the piston was 20 lb. (a) Determine the undrained shear strength (c) of the clay. Express your answer in both psi and psf. (b) What load would have to be applied to the load piston of th etriaxial cell to fail an identical sample of the same clay with a cell (confining) pressure of 40 psi? 2. Estimate the unconfined compressive strength, q u , of a sample of normally consolidated clay taken from a depth of 40 feet in the soil deposit shown below if the “c/p” ratio for the clay is 0.32.
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Unformatted text preview: The soil deposit consists of 15 feet of sand underlain by clay. The water table is at a depth of 10 feet. The sand above the water table is moist and has a unit weight of 115 pcf; below the water table the sand is saturated and has a total unit weight of 128 pcf. 3. The following data were obtained from unconsolidated-undrained (UU) triaxial compression tests on samples of saturated, normally consolidated clay taken from the same depth: Test σ 3 (tons/sq. ft) σ 1 - σ 3 at failure (lbs/sq.ft.) 1 0.0 520 2 0.5 640 3 1.0 600 4 2.0 680 Plot the Mohr’s circles of stress for the four tests abd determine the undrained shear strength (c) for the clay. Note: The friction angle, φ , should be zero. Moist Sand γ =115 pcf Saturated Sand γ =128 pcf Saturated Clay: Liquid Limit: 70% Plastic Limit: 30% G S = 2.70 w=52% 40 ft 15 ft 10 ft...
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This note was uploaded on 06/21/2010 for the course CE 3400 taught by Professor Brentrosenblad during the Fall '09 term at Missouri (Mizzou).

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