Click for next page ( 102


The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 101
102 EQUATION SYMBOLS ENGLISH LETTERS--UPPERCASE Jn = joint set number. Jr = joint roughness number. Ab = cross-sectional area of the foundation base. Jw = joint water reduction factor. Ac = cross-sectional area of concrete inside of spiral K = normal stiffness of rock-concrete interface. steel. Kb = socket depth factor. Ag = gross cross-sectional area of concrete shaft. Kir = initial slope of p-y curve. As = surface area of the side of the foundation. Ko = in situ coefficient of lateral earth pressure. Ast = total cross-sectional area of longitudinal rein- Kp = coefficient of passive earth pressure. forcement. L = socket length. Av = area of concrete in the cross section that is effec- LM = length of equivalent fixed-end column consider- tive in resisting shear. ing lateral deflection owing to moment. Avs = cross-sectional area of shear reinforcement. LV = length of equivalent fixed-end column consider- B = foundation diameter. ing lateral deflection owing to shear. Bls = diameter of a circle passing through the center of LM = length of equivalent fixed-end column consider- the longitudinal reinforcement. ing rotation owing to moment. C = correlation factor relating point load strength to LV = length of equivalent fixed-end column consider- uniaxial compressive strength of rock; ing rotation owing to shear. correlation coefficient relating uniaxial compres- Ls = nominal socket length. sive strength to ultimate unit side resistance. Lt = total travel distance along socket wall profile for D = foundation depth; distance between point loads roughness determination. in point load test; rock-socket diameter. M = bending moment. D s = depth of embedment in rock; thickness of soil N = standard penetration test value. layer overlying rock. N60 = corrected N for field procedures corresponding to E = elastic modulus; modulus of deformation. 60% hammer efficiency. Eb = elastic modulus of rock mass below the shaft Nc = bearing capacity factor. base. Ncr = bearing capacity factor. Ec = elastic modulus of the concrete shaft. Nq = bearing capacity factor. Ed = small-strain dynamic modulus. N = bearing capacity factor. Ee = effective elastic modulus of concrete shaft. N = bearing capacity factor. Eir = initial elastic modulus of rock mass. OCR = overconsolidation ratio. EM = rock mass modulus of deformation. P = axial load acting on a drilled shaft; load at rupture Ep = elastic modulus of the pile (shaft) material. in a point load test. Er = elastic modulus of intact rock; modulus of rock Pr = factored axial resistance. mass above the base. Pu = factored axial load. ER = elastic modulus of intact rock. Pz = axial load on a deep foundation. Es = elastic modulus of the shaft. Q = Tunneling Quality Index. G* = equivalent shear modulus of rock mass. Q' = modified Tunneling Quality Index. Gr = shear modulus of the elastic rock mass. Qb = load transmitted to the base of a rock socket; ul- GSI = Geological Strength Index timate resistance at the socket base. H = horizontal load acting on a drilled shaft. Qc = compressive force applied to the top of a drilled ID = slake durability index. shaft. IGM = intermediate geomaterial. Qi = intercept on the vertical axis (wc = 0) of axial Is = uncorrected point load strength index; moment of load-displacement curve. inertia of reinforced-concrete shaft. QOC = Osterberg cell test load. Is(50) = point load strength corrected to a diameter of Qs = total side resistance (force). 50 mm. Qt = total compressive load applied to the top of the I = dimensionless influence factor for elastic shaft. deformation. REC = average percent recovery of rock core. J = coefficient used to evaluate ultimate lateral resis- RF = roughness factor. tance in soil; bearing capacity correction RMR = rock mass rating. factor that depends on the ratio of horizontal dis- RQD = rock quality designation. continuity spacing to socket diameter. SRF = stress reduction factor. Ja = joint alteration number. S = joint spacing.

OCR for page 101
103 S1 = slope of the initial portion of axial load-displace- u = lateral displacement at the groundline of socketed ment curve. shaft. S2 = slope of the full-slip portion of axial load-dis- w = distributed load along the length of the shaft. placement curve. wc = axial displacement at the top of a socketed shaft. Vc = nominal shear resistance provided by concrete. xr = depth below rock surface. Vn = nominal shear resistance of reinforced concrete. y = lateral deflection of a deep foundation. Vp = compressional wave velocity. z = depth below rock mass surface. Vr = factored shear resistance of reinforced concrete. zy = depth of yielding in soil and/or rock mass. Vs = shear wave velocity; nominal shear resistance provided by transverse steel. GREEK SYMBOLS--UPPERCASE ENGLISH LETTERS--LOWERCASE r = dilation or increase in shaft radius. r = mean roughness height. a = empirical constant in HoekBrown strength cri- rh = average height of asperities. terion for rock mass. b = empirical factor to account for effect of rough- GREEK SYMBOLS--LOWERCASE ness on side resistance. c = rock mass cohesion; soil cohesion. = ratio of design to ultimate unit side resistance; ratio cpeak = peak interface adhesion. of rock mass modulus to modulus of intact rock; cresidual = residual interface adhesion. empirical adhesion factor relating unit side resis- cu = undrained shear strength. tance to uniaxial strength of intact rock. d = effective shear depth of reinforced concrete. = total unit weight of rock or soil. ds = socket diameter. ' = effective unit weight of rock or soil. f = shear wave frequency (hertz). r = relative shear displacement between concrete and fc' = compressive strength of concrete at 28 days. rock. fdes = design unit side resistance. M = lateral deflection owing to moment. fsu = ultimate unit side resistance. V = lateral deflection owing to shear. fy = yield strength of reinforcing steel. = strain. kir = dimensionless constant used in p-y curve = Poisson's ratio. criterion. c = Poisson's ratio of concrete. krm = constant used to establish the overall stiffness of b = Poisson's ratio of rock mass beneath the base of a p-y curve. mb = empirical constant in HoekBrown strength cri- a rock socket. terion for rock mass. r = Poisson's ratio of rock mass. n = ratio of rock mass modulus to uniaxial compres- c = construction method reduction factor. sive strength of intact rock. = mass density. p = lateral soil or rock reaction per unit length of s = ratio of spiral steel reinforcement volume to vol- foundation. ume of concrete core. p1 = limit pressure determined from a pressuremeter '1, '3 = major and minor principal effective stresses. test. 'h = horizontal effective stress. pa = atmospheric pressure. n = interface normal stress; fluid pressure exerted by pA = horizontal active earth pressure. concrete at the time of placement. pL = limit normal stress. p' = preconsolidation stress. po = at-rest total horizontal stress. v = vertical total stress. pur = rock mass ultimate lateral resistance. v' = vertical effective stress, pult = ultimate lateral resistance of soil or rock mass. = shear strength. qu = uniaxial compressive strength of intact rock. max = shearing resistance at shaft-rock interface. qult = ultimate bearing capacity. = shaft rotation. qt = split tensile strength. M = rotation owing to moment. r = radius of drilled shaft. V = rotation owing to shear. rs = nominal socket radius. = friction angle; resistance factor. s = empirical constant in HoekBrown strength cri- ' = effective stress friction angle. terion for rock mass; vertical spacing of the ties peak = peak interface friction angle. or pitch of the spiral for shear reinforcement. rc = residual angle of interface friction between rock sc, s, sq = shape factors used in bearing capacity analysis. and concrete. sv = vertical spacing between discontinuities. residual = residual friction angle. td = aperture (thickness) of discontinuities. = angle of dilation.