A circular footing with a radius of r = 4.0 ft will be embedded D = 2 ft in uniform clay. The topof the foundation is at the surface. The water table is at the ground surface.An intact sample of the clay with Gs=2.75 was obtained using a thin-walled Shelby tube from adepth of 10 ft below the ground surface. The sample was saturated and has a gravimetric watercontent of 45 %. Estimate its void ratio e0 and total unit weight y _in pcf.Ovp' = 800psfVoid Ratio1.51.41.31.21.11.00.90.8do100.102z/r, depth in radii6789Cr = 0.071001000Effective Stress (psf)0.2 0.3 0.4 0.6 0.81.07.010.0Cc = 0.38.09.05.06.0I, stress in percent of surface contact pressure23456 8.10100003.02.5(2.0)1.2520 30 40 50 60 80 1001.0PAG0.75Note: Numbers on curvesindicate offset distancesin radii, x/r.2rZ0.50₂-KABX0.25IX q1000,10FIGURE 4.10 Chart for calculating the increase in vertical stress beneath a uniformly loaded circular area.(From NAVFAC DM-7.1, 1982, and Foster and Ahlvin, 1954; reproduced from Holtz and Kovacs, 1981.)

An intact sample of the clay with Gs=2.75 was obtained using a thin-walled Shelby tube from a depth of 10 ft below the ground surface. The sample was saturated and has a gravimetric water content of 45 %. Estimate its void ratio e0 and total unit weight y _in pcf.

An intact sample of the clay with Gs=2.75 was obtained using a thin-walled Shelby tube from a depth of 10 ft below the ground surface. The sample was saturated and has a gravimetric water content of 45 %. Estimate its void ratio e0 and total unit weight y _in pcf.

Structural Analysis

6th Edition

ISBN:9781337630931

Author:KASSIMALI, Aslam.

Publisher:KASSIMALI, Aslam.

Chapter2: Loads On Structures

Section: Chapter Questions

Problem 1P

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A CU triaxial test was carried out on a silty clay that was isotopically consolidated using a cell pressure of 125 kPa. The following data were obtained: Axial load (kPa) 0 5.5 11.0 24.5 28.5 35.0 50.5 85.0 105.0 120.8 Axial strain, E₁ (%) 0 0.05 0.12 0.29 0.38 0.56 1.08 2.43 4.02 9.15 Au (kPa) 0 4.0 8.6 19.1 29.3 34.8 41.0 49.7 55.8 59.0 (a) Plot the deviatoric stress vs. axial strain and excess porewater pressure vs. axial strain, respectively. (b) Determine the undrained shear strength (su). (Note: we assume that the sample reaches failure). (c) Determine the total principal stresses (0₁,03) and the effective principal stresses (0₁, 03') at the failure, respectively.
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