GGU-RETAIN: Passive earth pressure

The coefficient of passive earth pressure can be calculated using several methods:

• DIN 4085:2017,

• DIN 4085: 2017 planar slip surfaces,

• Streck,

• Caquot/Kerisel,

• DIN 4085:2017 planar slip surfaces/Caquot/Kerisel,

• Culmann.

The earth pressure after Culmann is acquired by varying the slip surface angle (see Piling Handbook 1977). The forces at the earth pressure wedge are calculated using a slice method.

The Mohr/Coulomb (root) approach is obsolete and should no longer be used!

The passive earth pressure acting on soldier piles is calculated after Weißenbach (EAB R 14). When the soldier piles are so close together that the effects of passive earth pressure overlap, the calculated values should be reduced. The passive earth pressure with and without overlapping must be determined for this purpose. Passive earth pressure acting on soldier piles without an overlap effect takes the shape of a parabolic curve and depends, amongst other things, on pile width. GGU-RETAIN calculates both values (with and without overlap effect) for all subdivisions. The lower of the two values obtained is then used in the subsequent analysis. Thus, in a graphic visualisation of passive earth pressure acting on a soldier pile, part of the curve may be parabolic, while another part is linear.

DIN 4085:2017 stipulates that planar slip surfaces may be adopted for analysis up to a friction angle ≤ 35° and a wall friction angle ≤ -2/3 phi. This returns more favourable earth pressure coefficients.