The apparent earth pressure acting on diaphragm wall is chosen as per the type of soil existing in the field. For each strut we get an effective zone over which the earth pressure acts. Usually the earth pressure zones extend from centerline of one strut to that of the other, which implies that each strut takes the earth pressure on either halves upto half the vertical spacing ( ) . As shown zones 1,2,3 apply pressure on the struts 1,2,3. For zone 4, it is assumed that the soil in that portion does not apply pressure and it is taken up by the underlying soil.

Each strut load is calculated by multiplying the effective area of action of earth pressure with the apparent earth pressure (p). Usually the vertical spacing of the struts are taken between 3-4 m. The highest strut load is taken up for choosing the section of the struts and same section is provided throughout.