Passive Pressure on a retaining wall.

[connect2]

Help me here if possible, cantilever retaining walls;

Ok so I can visualize active pressure acting on a wall. displacemant, rotation, or deflection of the wall
I can visualize at-rest pressure on a basement wall.
I can visualize passive pressure on the low side of a retaining wall and it's contribution to sliding and overturning stability when driven by the active pressure on the opposite side of the wall, if you want to use it.
But I can't visualize passive pressure acting in any other instance.
In any of the pseudostatic seismic analaysis methods, such as the M-O method and all its short comings, how is it possible that the wall can move towards the fill and a passive pressure result?
Would not the same movement causing the wall to be 'pushed' into the fill also move the fill in the same direction as well?
So where or how does passive pressure come into play in the seismic design of a retaining wall?

Thanks.

 

[fattdad]

there is inertia that develops during seismic motion. The ground shakes, imparts a force on the wall, which moves in response to that force. The ground then moves in the opposite direction and there's a lag as the wall is moving in the other direction. That will mobilize passive resistance.

f-d

¡papá gordo ain’t no madre flaca!