Pile Pushover Analysis and p-y curves

[ChiEngr]

I have a question regarding lateral pile analysis that I am trying to wrap my head around.

I have an analysis of a single drilled shaft that I am working on using LPile. I performed a pushover analysis to see at what level of pile head displacement that a plastic hinge would develop in the pile. The results of this analysis are shown below:

Basically, the pile will develop a plastic hinge somewhere beyond 10” of lateral deflection per the moment vs deflection diagram shown in the first image above. This correlates to lateral shear force at the pile head of around 75 kips.

Now, if I look at the generated p-y curves for this model, I obtain the following:

That is, around 1.35” of pile head (?) deflection, the soil cannot accept any more load with increasing displacement. Does this mean that the soil has failed and that a plastic hinge will never develop (as it would require over 10” of lateral displacement)? I am confused as to what happens with the structural behavior beyond this 1.35” of displacement.

My apologies if this question is simple; I am a structural engineer, not a geotechnical engineer, but I am eager to learn!

 

[Smoulder]

Plot reaction vs depth and displacement vs depth. Will be easier to see what's happenjng. But basically the soil near ground level will go plastic with the lower layers stabilising the pile as long as it goes deep enough.