As for how the spillway damage started, the  issue was uplift forces.

至于溢洪道损坏是如何开始的，问题在于升力。

So, being underwater already starts to destabilize  them, because it adds an uplift force.

因此，在水下已经开始破坏它们的稳定性，因为它增加了升力。

If all  the uplift forces exceed the weight of the slab, it's going to move.

如果所有的升力超过了平板的重量，它就会移动。

When this stagnation  pressure acts on the bottom of a concrete slab, it creates an additional uplift force.

当这种停滞压力作用在混凝土板的底部时，会产生额外的升力。