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Project Design Mogul Tunnel Bulkhead <br />10.6' x 9,5' (9' Thick. Station 2+411 <br />Notation continued: <br />V n =nominal concrete shear strength (lb/ft) <br />V „ =factored concrete shear strength (Ib/R) <br />v9 = rebar shear stress (psi) <br />W =total bulkhead load (Ib) <br />Z =height of rock to prevent hydrofrac (R) <br />~ ovb =Overburden rock stress per ft of depth (psi) <br />ru rs =factored static fluid bulkhead load (psf) <br />w r~ =factored static fluid bulkhead earthquake <br />load (psf) <br />cu ae =factored line of sight fluid bulkhead <br />earthquake load (psf) <br />ra ~ =factored bulkhead concrete <br />earthquake load (psf) <br />a e =flexural stress (psi) <br />a mex =maximum principal stress (psi) <br />a,,,;,, =minimum principal stress (psi) <br />a ovn =overburden stress (psi) <br />By JFA Date 8121/03 <br />Sheet 2 of 6 <br />Inputs continued• <br />Load increase factors <br />Fluid static load, ~ fs := 1.40 <br />Earthquake acceleration, static fluid <br />load <br />Eart~rquake acceleration load, line of <br />sight <br />fluid and bulkhead masses, <br />Bulkhead leneth for hydraulic pressure Qradient: <br />Maximum pressure head, p := H 44 Pst p = 94 psi <br />~ fe := 1.05 <br />~ ~ := 1.40 <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 L = 2.3 <br />41 <br />Depth below surface to prevent hvdofrac of rock around tunnel: <br />Allowable formation breakdown pressure, B p := p B p = 94 psi <br />Overburden ressure, r ft of of d Y <br />p ~ ~~ ~ ovb '- 144 ~ ovb - 1.176 psUft <br />Height of rock to prevent hydrofrac, Z := p Z = 40.2 ft <br />2'~ ovb <br />ft <br />.y~m,egevev~vm9n.vH <br />