How does quick sand form?

Answer 1

Quicksand is a form of fine sand that loses its supporting capacity and acquires the character of a liquid. It's usually found in hollows at the mouths of large rivers or along flat stretches of streams or beaches where pools of water become partially filled with sand and an underlying layer of stiff clay or other dense material prevents drainage.

The sand body behaves like a fluid because water flowing through the sand forces individual grains apart and prevents them from settling. The sand then loses its firmness and cannot support a heavy weight. Some natural sands are in a condition so loose that such minor disturbances as those caused by a footstep may cause the structure to collapse.

Answer 2

Quicksand forms when sand becomes saturated with water, creating a liquefied mixture that can no longer support weight. When disturbed, the sand loses its ability to bear weight and behaves like a liquid, trapping anything that comes into contact with it.