Transcript of "Active Wedge Behind A Gravity Retaining Wall Complete 2011"
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Modeling of the Active Wedge behind a Gravity Retaining Wall<br />By: Rex Radloff<br />14.531 Advanced Soil Mechanics<br />University of Massachusetts Lowell<br />Department of Civil Engineering<br />
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Rankine Active Wedge<br /><ul><li>Wall friction is neglected
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Back face angle (α) is 45 + φ/2</li></ul>φw<br />Rankine wedge behind a gravity retaining wall.<br />What if the above was not held constant? <br /><ul><li>How would the magnitude and location of Pa change?
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To what degree?</li></ul>Rankine stress distribution behind a gravity retaining wall.<br />University of Massachusetts Lowell 14.531 Advanced Soil Mechanics<br />2<br />
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Active Wedge with Reactions<br />W<br />Note:<br />The weight and centroid of the active wedge is a function of H, Wh, WBs, γ, α, θ, and β<br />The weight and centroid of the backfill is a function of H, WBs, Wh, γ, θ, and β<br />Active wedge with consideration towards θ, β, and φw<br />University of Massachusetts Lowell 14.531 Advanced Soil Mechanics<br />3<br />
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Modeling the Active Wedge<br />Known<br />Wall dimensions and materials.<br />Soil and wall shear strength parameters.<br />Grade of overburden soil.<br />Solve for<br /><ul><li>Angle θ of the front face of the active wedge.
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Failure Analysis: H/Wh = 3.4 <br />|e| ≤𝑏6 2.08 ft<br /> <br />The increase in Pa lead to a below acceptable FS for overturning.<br />The greater distance between the Pa vector and pt.O led to a below acceptable eccentricity. <br />University of Massachusetts Lowell 14.531 Advanced Soil Mechanics<br />7<br />
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Pa vs. α vs. θ<br />φw = 34⁰<br />Line of intersection<br />φw = 0⁰<br />Produced using Mathematica<br />University of Massachusetts Lowell 14.531 Advanced Soil Mechanics<br />11<br />
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Conclusion<br />The active force (Pa) depends on the angles θ, α, and φw found among the active wedge.<br />Any deviation between the calculated active force behind the same retaining wall depends on the combining effects of θ, α, and φw found among the active wedge.<br />As the angle θ decreases, the Pa will increase as well as the variance between the Pa calculated with and without wall friction.<br />Hard to openly predict the influence on the failure criteria<br />University of Massachusetts Lowell 14.531 Advanced Soil Mechanics<br />12<br />
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Is it worth consideration?<br />University of Massachusetts Lowell 14.531 Advanced Soil Mechanics<br />13<br />Yes<br />
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