2007-11-13_REVISION - M1977300 - Laserfiche WebLink

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I I/ I:7/ZVvf IJ.oo r A A Project, Pierce Adit Tunnel Bullhead, Sta. 3+04 12' Thick, 12' Wide, .12' High, #6 Rebar C k)'):1 / O I b By M.F-L/JFA Date 10/30/07 Sheet 2 of 8 Notation continued: VI, = nominal concrete shear strength (lb/ft-) VU = factored concrete shear strength (lb/ft) V.; = rebar shear stress (psi) W = total bulkhead load (lb) Z = height of rock to prevent hydrofrac (ft) a„,b = overburden rock stress per ft depth (ft) core = factored static fluid bulkhead load (psf) Wfsc = factored static fluid bulkhead earthquake load (psf) Wrc = factored line-of-sight fluid earthquake bulkhead load (psf) o)fbe = factored concrete bulkhead earthquake load (psf huts continued: Load increase, design factors Fluid static load, q5 s := 1.40 Earthquake acceleration of static fluid fife := 1.05 load, Earthquake acceleration of line-of-sight Oea := 1.40 impounded fluid and bulkhead loads, v„I = nominal limiting sl:Iear stress, wi,/1-1<2 (psi) vri2 = nominal limiting shear stress, cob/Lt = 2-5 (psi) Cr. = flexural stress (psi) cr,,,i„ Bp = minimum contact grout pressure (psi) es,,,nxsi, = maximum contact grout pressure (psi) Bulkhead leneth for allowable hydraulic nressure gradient: II• Maximum (design) hydraulic pressure, p := ry w 144 psi p = 52 psi Minimum contact grout pressure, Q'?ningp = Psi 144 Qmingp = 54.2 Psi Maximum contact grout pressure, °•max 2-Bw•'Yr Bp - 144 psi Qmaxgp = 283 psi Allowable 41 psi/ft pressure gradient for low-pressure grouting of upper part of concrete/rock contact: Required bulkhead thickness for low-pressure contact grouting, Li,p -L ft Li,P = 1.27 ft 41 Depth below surface to prevent hydrofrac of rock around tunnel: Available formation breakdown pressure, Overburden pressure, per ft of depth, Height of rock to prevent hydrofrac Bp P -1 r Aovb 144 Z _ BP 2*Aovb 131, = 52 psi Dov1, = 1.132 psi/ft Z=23 ft