Walking somewhere in nature, enjoying the charm of flowering plants, listening to birds whistling funny songs, you can accidentally be trapped in the quicksand. But you should immediately warn that it’s not so scary, as shown in some movies of the genre of horror. Yes, of course, it is better to avoid them, but at the same time you should not be afraid. There are several consistent rules, the knowledge of which will help to avoid such situations.
What is quicksand generally? This is a really interesting natural phenomenon, but no peculiar type of soil. A mixture consisting of fine-grained material, clay and water (in desert places - a mixture of sand and air). It looks solid, but becomes unstable when pressure is applied to its surface. It is formed when water oversaturated such soil. Normal, naturally occurring sand (quarry, mountain, sea) consists of tightly packed grains that form a hard mass (approximately 25 to 30 percent of the space between the grains is filled with water or air). Since many grains of sand are elongated, their separation can occur, and then the voids will make up from 30 to 70 percent of the mass. This mechanism is similar to a house of cards, when the space between the cards is much larger than the space occupied by them. The liquid helps to create a liquefied soil that is not able to withstand the weight load.
Quicksand can form in stagnant and flowing waters flowing upward (as in artesian springs). Water jets directed upwards resist gravity and inhibit soil particles. Saturated sediments may look quite solid, but a small mechanical stress on their surface initiates liquefaction. This leads to the fact that sand is formed into a suspension and loses its strength. Due to the amortized water, quicksand, liquefied deposits, spongy, fluid-like, soil texture are formed. Objects falling into such an environment fall to a level at which their weight is equal to the weight of the displaced mixture (from soil and water). Liquefaction is a special case of the phenomenon under consideration. So, in the event of an earthquake, pore pressure instantly increases in shallow groundwater. Wet liquefied soil loses its strength, which leads to the collapse of buildings and other objects located on its surface.
Quicksand is formed where natural sources exist, in marshy or humid places, near rivers, on beaches, although most often they are not so easy to determine. If you suddenly fall into them, then they retreat quickly and gently, reacting with an interval of a couple of seconds. They are a non-Newtonian fluid, that is, at rest they represent a solid (gel-like), but the slightest effect on them causes a sharp decrease in viscosity. In the deserts, they are also found, but extremely rarely, where there are placers of sand, for example, on the leeward side of the dunes. But the decline is limited to a few centimeters, because as soon as the air in the voids between the sand grains is removed (and this happens quickly), they are again compacted.