194_CEG 4012 Notes Fall 2011 CEG 4012 Notes Fall 2011

# 194_CEG 4012 Notes Fall 2011 CEG 4012 Notes Fall 2011 -...

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SL20 !:.l.; !:.x· ~I I~ o Resisting Moment: M R =RLc,!:.L, +RLN, tan¢, = RLc,!:.x, seca, +RLN,lan¢, Simplified Method of Slices Bishop (1955) o Assume side force is normal to slice (8 = 0). E i * E i• 1 o Cannot sum forces on failure plane as before because get aE term, but can sum forces in vertical direction: :LFv =N l cosa; +Ujcosa j + T, sinai = WI o Define: T _ cjffi{jsecCt i +N j tan¢l, ,- FS a Substitute for Tj in F v equation: N U cI8xlsecal+Nltan41l· W I cosa l + I casal + FS Sinal = 1 o Solve for Ni: W U Ci~l tan (Xl W Av C,dx l tan "j ,- ICOSCt.;- FS j-U,UAI FS N = ---;::-:-:~':'-- = ---c::=-'~- 1 ~n~sin~ t~~sin~ casa, + FS cos a, + FS o Driving Moment: o Faclor of Safely: Me =RL:Wlsina l FS = RLc,lIx, seca, +RLN, tan\$, = Lc,!:.x, seca, + LN, tan\$, RLWisina; L:Wjsina j W ... c,.6.x l tan OJ i - u,U.x 1 L c,!:.x, sec a, + L I '" F.S Ian \$, cos (Xi + an Of, sin Ct, o Substitule for N,: FS = FS LW,sina, r----,,-------~~
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Unformatted text preview: L[(C,lIx, +(W,-u,!:.x,)tan\$,(~JJ o SoÂ· IES = where III = C"OS 0. 1 . ..;'[,W sin a,' L __ ~~~~!. .-lJ 80 .. 50 I.) 30 o 10 20 a DogfOOS â€¢-a~+a 1.0 '1-V 0.8 ..... 2 0.' ~~--t---. 0.2 0.' o 0.4 L"-. o.~~ r-:: c-----~ 0.8 0.2 8 ~ i'--. V~.~ v...... o,oano V 8 V/ V !j. ...--VÂ·j' TFSI "-. 4 1.0'" r-o' 8 1. â€¢ â€¢ ....L o. O.-40-30-20-10 H o c 1. "S iii Eol:!:. 15 c â€¢â€¢ S 1. â€¢ â€¢ .g-=-> â€¢ eo:. o. Iterative solution: ~ guess FS, ~ calculate moo--> calculate FS,--> sel FS, = FS,---+ recalculate mui and FS ,--> repeat unlil FS, = FS, o J3is~op method widely usea, reas'onablyaccurate-saMion, .I!Â§Jl.ful for computer-<lnaljis,s, poor:{unconservalive) fai' large negative a...
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