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I I! IJl GV'v r r ? v r r rr.. Project, Steve Adit Tunnel Bulkhcad. Sta. 2+65 10' Thick, 10' Wide, 101 High, #6 Rebar Notation continued: Vn = nominal concrete shear strength (lb/ft) V„ = factored concrete shear strength (lb/ft) V4 = rebar shear stress (psi) W = total bulkhead load (lb) Z = height of rock to prevent hydrolrac (ft) Ao„b = overburden rock stress per ft depth (ft) coy:, = factored static fluid bulkhead load (psf) Wi;su = factored static fluid bulkhead earthquake load (psf) WIIC = factored line-of-sight fluid earthquake bulkhead load (psf) wtbe = factored concrete bulkhead earthquake load (psf) 3y M.EL/JFA Date 10/30/07 S.1-ieet 2 of S Inputs continued: Load ingress(: design factors Fluid static load, ? es := 1.40 Earthquake acceleration of static fluid 0fo := 1.05 load, Earthquake acceleration of line-of-sight 0,ta 1.40 impounded fluid and bulkhead loads, v, i = nominal hiniting shear stress, wb/Li<2 (psi) V,12 = nominal lin'.iting shear stress, wv/Lt = 2-5 (psi) a, = flexural stress (psi) minimum contact grout pressure (psi) e,,,avgp = maximum contact grout pressure (psi) Bulkhead length for allowable hydraulic pressure gradient: H'-Yw Maximum (design) hydraulic pressure, p := 144 psi p = 52 psi $w'7w Minimum contact grout pressure, Qmingp 144 psi 0mingp = 49.8 psi 2-B,'1'r Maximum contact grout pressure, Q maxgp 144 psi CmaxgP = 260 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,,, := 41 ft L11p = 1.27 ft Depth below surface to prevent hvdrofrac of rock around tunnel: Available fonnation breakdown pressure, Overburden pressure, per ft of depth, Height of rock to prevent hydrofrac BP P Aovb •= 144 Z Bp 2 •vovb I31, = .52 psi Do,,b = 1.132 psi/ft Z=23 ft