Estimation of settlement due to dewatering

I won't try to directly answer. However, this would appear to be the same sort of a computation or several that we do for determining settlement due to surcharging. Each involves a gradual application of load. In the surcharging case if we try to make the computations for instant load application, we find that settlement has already started by the time the load is fully on.

In my cases most of the time the soils are layered to some extent and the drainage path is much shorter than test borings may imply. Result is, the computations generally are not very good at predicting time for the desired settlement occur. The actual time usually is well before the computations might estimate. Therefore, I depend more on test fills than any computation.

For drainage, I would think knowing the details of possible shorter drainage paths might help a lot. For a large job, perhaps a test pumping would be possible.