Yeah.

Reason that's important is that my double shaking table test just extended what Jeff Martin had already found, which is that as you accumulate cycles of loading, whether they're regular or irregular, there's a hardening effect on the modulus and a decrease in the amount of settlement.

So you have to track the effect of the stress and strain history as you work through, uh, the input time history, and ideally, you track both.

You've gotta track both components.

Um, uh, and the result is, uh, you tend to accumulate settlement faster- But because you are sh- you have faster accumulation of settlement and the addition slows down as you get more settlement, because the way Jeff Martin and I reduced the data, the settlement per cycle is a function of settlement up to that point.

Yeah.

So they ended up with very ragged, uh, chunks of desert alluvium.

But they'd, you know, the, the size of a big triaxial device or more.

Design and construction defects, you know?

Yeah.

Yeah.

And so as a resident of California, uh, we're, we're used to hearing about California water, uh, policy and politics, which I got more involved in at one point.

Uh, but it's all about- Shasta Dam, Oroville Dam, and transport- Yeah ... of water to- Yeah ...

the Central Valley in Southern California.

It's not about- Yeah ... uh, flood control for Los Angeles, which is still a very important issue.

Okay

Yeah, yeah.

Uh, but relative to what we're heading towards, there are, there are four more recent articles.

And I, I just have to mention that, that in that writing about slope stability analysis and, uh, tailings dams failures, I came to the conclusion that we shouldn't be talking about slope stability analysis anymore.

That's kind of passe.

Um, conventional slope stability analyses, like the simplified method for evaluating liquefaction potential- Which I so admired when it was first published by Seed and Iversen when I first- Yeah ... heard Harry Seed present it, is sort of out of date.

It only is of use when there isn't any problem.

Just like conventional limit equilibrium slope stability analyses are fine, but they're really only use- useful when there is no problem.

Yeah

yeah

and so uh When it came time to retire from PG&E, he became the leading consultant worldwide on how to properly build rock fill embankments with or without earth cores or some other impermeable membrane on them.

And off the top of his head, he could design an earth and rock fill dam and say you know you want to go with a fairly thin but not too thin earth core have two filter zones downstream one filter zone upstream you can pack the rock fill the inside of it in six foot lifts and then the outside of it in three foot lifts and then have rip rap on downstream face and the top of the upstream face and um if you can find good rock then you can build this with one to 1.8 uh outside slopes upstream and downstream and so literally he designed the dam in in one afternoon.

But while they had a very good geologist who came from the Australian equivalent of the Bureau of Mines and was seconded to the department, who was already working on the job, they didn't have anyone in that group who knew anything about soils or basically even knew how to go about looking for an appropriate borough area for soils.

Neither did I, but I was willing to have a crack at it and somewhat eager to get out of structural engineering design.

So I said, sure, I'd I'd be really interested in doing that.

So this must have been maybe November of 1964.

Harry