[simne]

> There was a lot of research into statistical models of slips – in particular boudler movement and how they break up – which didn't really work.

You remembered me history from Harrington Emerson (The twelve principles of efficiency).

As railroad worker, he frequently seen rails flooded by rain. Exist at least two solutions.

First, to build Embankment, so rails will be much over water level, which will cost at least few millions dollars. And sure, suffer all problems with slips in future.

Second, to dig trench near rails (in most cases it is obvious, where to dig) and just constantly pump out water from it, so all water from rain will be pumped out - it will cost few hundred dollars for digging and less than thousand dollars per year to support (100 years ago, now, sure more). No slips at all, because when ground is dry, no slip happen.

Guess, what usually chose management and why? :)

[simne]

BTW, greetings from Kyiv, Ukraine, country now at war, and city, whole build on hills and over hundred years spent to build drainage system under hills so last decades slips are very rare.