When a sandpile fails, clumps rather than individual grains tend to fall.
From the nature.com
The soil was a loamy sort of sandpile that was drier than a bone.
From the dailynews.com
Four stories off a warehouse roof into a sandpile.
From the time.com
There was, of course, more than a grain of truth in everything I said, but those grains, no matter how numerous, need not have become the sandpile that crushed the life out of love.
From the theatlantic.com
More examples
Sandbox: a plaything consisting of a pile of sand or a box filled with sand for children to play in
The Abelian sandpile model, also known as the Baku2013Tangu2013Wiesenfeld model, was the first discovered example of a dynamical system displaying self-organized criticality. It was introduced by Per Bak, Chao Tang and Kurt Wiesenfeld in a 1987 paper.