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Larry Perino Page 8 August 17, 2000 <br /> Appendix A. Terry Tunnel near portal bulkhead design calculations (Continued) <br /> Hydraulic pressure gradient for 7-ft thick bulkhead: <br /> Low pressure grouting of concrete-rock contact but not rock, gradient allowable=41 psi/ft <br /> (Garrett & Campbell-Pitt, 1958, Chekan, 1985, p11), with factor of safety of 4 <br /> Terry Tunnel bulkhead, maximum pressure head <br /> Hyw 469(62.4) _2O3 Sl <br /> p— 144 = 144 11 <br /> Required bulkhead length with low pressure grouting on concrete/rock bulkhead contact: <br /> L = 4i = 403 = 4.95ft <br /> Pressure gradient with L= 7 ft pg = L = 273 = 29.0 psi/ft <br /> Factor of Safety against water leakage along concrete/rock contact around 7-ft thick <br /> bulkhead is: <br /> FS = 2910 = 1.41 <br /> Concrete shear on Terry Tunnel perimeter: <br /> fs = 2 f� =2 3000 = 110 psi (ACI 318-95, Sec 11.3.1.1) <br /> _ pill _ 203(13)12.7 _ 33500 _ <br /> L 2(h+i% 2(13+12.7)110 5650 — 5.93 ft <br /> W=phl =203(13)12.7(144) =4,830,000 lb <br /> W _ 4830000 _ 4830000 _ <br /> Va _ [2(h+l)1U144) [2(13+12.7)]7(144) 51800 — 93.2 psi <br /> 4 110 = L18 <br /> F`S 93.2= vs — <br /> Plain concrete deep beam bending stress design, Terry Tunnel (ACI 318-95, Sec 9.9.2.5, 18.4.1(b), <br /> & ACI 318-71, Sec 9.2.1.5) <br /> Terry Tunnel bulkhead, for 469-ft hydraulic head (203 psi pressure head): <br /> (o=U= 1.4p(144) = 1.4(203)144 =40,900 R <br /> 2 ao900(12.7z) <br /> M.= 8 _ = 824,600 ft•lb <br />