Taking moments of all forces about anchor point M,

(a + h – e - ) – (h – e + a +2b/3 ) = 0

Where,

a is the distance of the zero earth pressure point below dredged level,

h is heigth of the sheet pile above the dredged level,

e is the distance of the anchor from the top level of sheet pile, generally taken as 1 to 1.5m,

is the distance between point of application of force and O point.

Substituting the value of in the above equation,

(a + h – e - ) – ( – ) b (b/2) (h – e + a +2b/3 ) = 0

The above equation can be written as,

( – ) ( /3) + ( – ) ( /2) (g+a) – f = 0

or

where, f = a + h – e - and g = h – e.