Notation The effective bearing capacity qf=qf·o The effective surcharge q's=qs·0 The effective(submerged)unit weighty' Ysat Yw These quantities are usd because they give the variation of stresswh depth.Fo under the footing the total vertical stress,pore pressure and effective vertical stress at any depthzare =qr +Yz u=u。+YwZ o:G,-u=qi y'z Following through the same analysis as before but using the effective stress failure criterion which is given by N c'cot o;+c'cot中 gives qi =q:N +H(Ni-1)+e'cote(Ni-1) which can be more generally writtenas qf=qN。+YN,+cN 2 ersgmgapacftosactaitaotocegnombdoceNacthitctoacanme qr q'f uo The be The simple analysis considered so far has soil strength pa ·rate of loading(d ndranedl g0 wa (a turated) foundation shape(strip footing,square or circle) Additional factors which also influence the capacity are Notation The effective bearing capacity q’f = qf - uo The effective surcharge q’s = qs - uo The effective (submerged) unit weight’ = sat - w These quantities are used because they give the variation of effective stress with depth. For example under the footing the total vertical stress, pore pressure and effective vertical stress at any depth z are   v qf = + z u u z = o + w   =  − =  +   v v u qf z Following through the same analysis as before but using the effective stress failure criterion which is given by N c c      =  +    +   1 3 cot cot gives  =  + ( ) ( )  q q N − +   − H f s  N c N   2 2 2 2 1 cot 1 which can be more generally written as  =  +  q q N +  B f s q N c Nc   2 where the bearing capacity factors are identical to those given before. Note that the total bearing capacity is qf and qf = q’f + uo The bearing capacity is a function of many factors. The simple analysis considered so far has accounted for • soil strength parameters • rate of loading (drained or undrained) • groundwater conditions (dry or saturated) • foundation shape (strip footing, square or circle) Additional factors which also influence the capacity are