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Project Design Mogul Tunnel Bulkhead <br />8' z 8' (9' Thick, Station 2+41) <br />Notation continued: <br />V „=nominal concrete shear strength pb/ft) <br />V „=factored concrete shear strength (lb/ft) <br />vs = rebar shear stress (psi) <br />W =total bulkhead load Qb) <br />Z =height of rock to prevent hydrofrac (fi) <br />d opt =Overburden rock stress per ft of depth (psi) <br />w is =factored static fluid bulkhead load (psf) <br />w rse =factored static fluid bulkhead earthquake <br />load (psf) <br />w n~ =factored line of sight fluid bulkhead <br />earthquake load (psf) <br />w ~ =factored bulkhead concrete <br />earthquake load (psf) <br />a s =flexural stress (psi) <br />a m,ix =maximum principal stress (psi) <br />a rrun =minimum principal stress (psi) <br />a ovb =overburden stress (psi) <br />By JFA Date 7/4(03 <br />Sheet 2 of 6 <br />Inputs continued: <br />Load increase factors <br />Fluid static load, ~ fs := 1.40 <br />Earthquake acceleration, static fluid ~ fe := 1.05 <br />load <br />Eart~tquake acceleration load, tine of ~ ea := 1.40 <br />sight <br />fluid and bulkhead masses, <br />Bulkhead length for hydraulic pressure gradient: <br />H•y v: <br />A!a°;;/c:m i:ress_:. _ :.__ ', ;. ~ 144 r., P = 94 psi <br />Allowable pressure gradient of 41 psi/ft for low-pressure (-50 psi) grouting of upper part of <br />concrete/rock contact. <br />Required bulkhead length for low-pressure grouted concrete/rock contact := P <br />41 <br />Depth below surface to prevent bydofrac of rock around tunnel: <br />Allowable formation breakdown pressure, B p := p <br />Overburden pressure, per fl of of depth, e Y r <br />ovb '= 144 <br />Height of rock to prevent hydrofrac, Z := p <br />2'e ovb <br />L = 2.3 ft <br />B p = 94 psi <br />e ovb = Lzo1 psi/ft <br />Z = 39.3 ft _ <br />lA~Bkdl~ ]/IN90312~31 Phi <br />