Ladies and gentlemen, start your
pickups and drive across that open
construction site. Sinking in mud up to
the axles? Harsh! Time to build a road.
The Physics of Mud
When you push on wet soil with sufficient
stress — and it doesn't have to
be much — the soil squirts out of the
way. This is what happens with your
trucks on a muddy job site (not that
you ever actually do it): The wheels
press on the wet soil, the mud pushes
out of the way, and down you go.
The stress level needed to displace
mud is about 500 pounds per square
foot. The footprint of a truck tire is