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<br />Project Design Koehler Tunnel Bulkhead <br />8.5' x 9' i12' Thick. Station 3+021 <br />Notation continued: <br />V o =nominal concrete shear strength (Ib/ft) <br />V „ =factored concrete shear strength (Ib/ft) <br />ve = rebar shear stress (psi) <br />W =total bulkhead load (lb) <br />Z = height of rock to prevent hydtofrac (ft) <br />~ ovb =Overburden rock stress per ft of depth (psi) <br />w is =factored static fluid bulkhead load (psfj <br />w r~ =factored static fluid bulkhead earthquake <br />load (psf) <br />w a~ =factored line of sight fluid bulkhead <br />earthquake load (psf) <br />w ~ =factored bulkhead concrete <br />earthquake load (psfj <br />a a =flexural stress (psi) <br />a max =maximum principal stress (psi) <br />a ,~,~ =minimum principal stress (psi) <br />a ovn =overburden stress (psi) <br />By JFA Date 7/21/03 <br />Sheet 2 of 6 <br />Inputs continued• <br />Load increase factors <br />Fluid static load, Q fs := 1.40 <br />Earthquake acceleration, static fluid ~ fe := 1.05 <br />load <br />Earthquake acceleration load, line of ~ ~ := 1.40 <br />sight <br />fluid and bulkhead masses, <br />Bulkhead IenQth for hydraulic pressure eradient: <br />H'Y µ, <br />Maximum pressure head, p ~ 144 psi p = 215 psi <br />Allowable pressure gradient of 41 psUft for low-pressure (-50 psi) grouting of upper part of <br />concretelrock contact. <br />Required bulkhead length for low-pressure grouted concreteJrock contacL• := P <br />41 <br />Depth below surface to prevent hvdofrac of rock around tunnel: <br />Allowable formation breakdown pressure, B p := p B p = 215 psi <br />Overburden sure ft of of Y <br />I~ > ~ ~~ ~ ovb '= 144 ~ ovb = 1.176 <br />Height of rock to prevent hydrofrac, Z := p Z = 91.5 ft <br />2'~ ovb <br />L = 5.25 <br />psi/ft <br />ft <br />rmwmi..mca ~mnvm wa vs+ <br />