2.2 Bearing capacity for footings on layered soils Case 2.Footing on layered -c soils with a,b same with case 1. Case 3.Footing on layered sand and clay soils a.Sand overlying clay b.Clay overlying sand Experimental work to establish methods to obtain qult for these three cases seems to be based mostly on models- often with B<75mm. Several analytical methods exist as well. Button(1953)used a circular arc to search for the approximate minimum(for the trial circle all in the top layer),give N.=5.5<2T 2.2 Bearing capacity for footings on layered soils ▪ Case 2. Footing on layered φ-c soils with a, b same with case 1. ▪ Case 3. Footing on layered sand and clay soils ▪ a. Sand overlying clay ▪ b. Clay overlying sand ▪ Experimental work to establish methods to obtain qult for these three cases seems to be based mostly on models￾often with B<75mm. ▪ Several analytical methods exist as well. ▪ Button (1953) used a circular arc to search for the approximate minimum (for the trial circle all in the top layer), give Nc=5.5<2π