Note for Foundation Engineering - FE By JNTU Heroes

Topics ( 3 )

Text from page-1

ADVANCED FOUNDATION ENGINEERING CLASS NOTES EARTH PRESSURES            smartworlD.asia At Rest Lateral Pressure Rankine Active and Passive Earth Pressure States Relations Between Earth Pressures and Wall Movements DIA – Dual Interfacial Apparatus Interfacial Friction and Adhesion Active and Passive Earth Pressure Coefficients Computation of a General Active Case Horizontal Pressure from Surface Loads Effect of Ground Water and Filter on Wall Pressures Earth Pressure due to Compaction Earth Pressure on Rigid Retaining Walls Near Rock Faces

Text from page-2

EARTH PRESSURES  Review Ch. 6 in H.Y. Fang, “Foundation Engineering Handbook” or Ch. 11 in J.E. Bowles, “Foundation Analysis and Design” (5th ed.) or Ch 7 in B.M. Das “Foundation Engineering” (7th ed.)  Design of earth-retaining structures requires knowledge of the earth, water, and external loads that will be exerted on the structures. AT REST LATERAL PRESSURE (a) Theoretical elasticity under conditions of lateral zero disp. (referring to effective stresses). (1) 2  1  2   3  1  E (2) 3  1  3  1   2  E ’ smartworlD.asia 3 = 2 = 0 for zero lateral yield for orthotropic or oedometer conditions ’ 23 (1) + (2) 2 3  2  2   3  ’  3 1     1  3  Ko   1   1 1  say K = h/v = 3/1 = 0.15 Ko = 0.18 = 0.30 = 0.50 Ko = 0.43 Ko = 1.00 PAGE 1

Text from page-3

(b) Empirical Correlations After Mayne & Kulhawy (1982) max min  First Reloading First Unloading Virgin Loading h OCRmax  OCR    max  v min smartworlD.asia  max  Reloading (empirical)  OCR 3 OCR  K o  1  sin   1sin    1  4  OCR max  OCR max    Unloading O.C. OCR = OCRmax → Ko = (1-sin ') OCRsin' Virgin loading N.C. OCR = OCRmax = 1 → Ko = (1-sin ') (Jacky, 1944) References: Mayne, P., and Kulhawy, F. (1982). "Ko-OCR Relationships in Soil", Journal of the Geotechnical Engineering Division, ASCE, Vol. 108, GT6, pp. 851-872. Kulhawy, F., and Mayne, P. (1990). Manual on Estimating of Soil Properties for Foundation Design, Electric Power Research Institute Report EPRI EL-6800, Palo Alto, CA. PAGE 2

Text from page-4

 OCR  OCR  K 0  K onc    m 1 r 1   OCR max   OCR max    Kulhawy & Mayne (1990) Substituting (see below) Konc = 1 - sin,  = 1-Konc → 1 -  = 1 - sin, mr = 0.75 brings to the equation previously presented smartworlD.asia Konc = (1 - sintc)  0.1(range) PAGE 3