12 Consider two identical circular tanks with a radius R of

1.2 Consider two identical circular tanks with a radius R of 4 m, each exerting a pressure at the surface of qo 60 kPa and with a 2 m spacing between their edges (see plan view below) Using the pressure bulb solution shown below calculate the vertical stress increments 6 m below point A due to the combined effects of the two tanks. 8 pts Plan view sa2 m Re4 m R 4 m Clearly identify the point(s) you are using on the pressure bulb solution Tank 1 Tank 2 2 1969 2 4 ANSWER: Vertical stress increment 6 m under A: Pa

Solution

the pressure increment will be due to both tanks

total pressure increment= pressure increment due to tank 1 + pressure increment due to tank 2

pressure increment due to tank 1:

x=4+2=6

R=4

x/R=6/4=1.5

z=6

z/R=6/4=1.5

pressure increment due to tank 1=0.15*60=9 kPa

pressure increment due to tank 2:

x=4

R=4

x/R=4/4=1

z=6

z/R=6/4=1.5

pressure increment due to tank 2=0.25*60=15 kPa

total increment = 9+15=24 kPa