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Unformatted text preview: below the base of the foundation: !1cr = 4·I·q I is the influence factor for stresses beneath the corner of a rectangle (thus the factor 4 in the above equations). I is determined based on m = n = B'/z = B/2z (assuming that the foundation is square; it mayor may not be square). For depth (z) we use the depth below the bottom of the foundation because that ls the dep!h from w~ere we know the stress changes_. _ ._ . _ Combining the changes in stress due to the soil removed and the foundation load placed back on: !1cr =4 ·1· yD f +4 ·1· q (continued on next page) Page 1 of2 or, !::.J:J = 4 .1·(qyOf) or, !::. .o = 4 ·1 .qnet where qnet = q yOf Thus, when the foundation is placed at depth and load is removed, we should use the "net" change in stress at the level of the base of the foundation to calculate the changes in stress at depth. Page 2 of 2...
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 Spring '11
 Rosenblad
 Geotechnical Engineering, Stress

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