Patent ID: 8322231

Claim:
An apparatus for measuring the force and displacement exerted by a rotating tire in soil/aggregate comprising: a hydrostatic actuation assembly having a pressure plate at near surface depths of soil/aggregate providing hydrostatic pressures in a liquid, said hydrostatic pressures being representative of force and displacement created by the downward forces exerted by a rotating tire in the soil/aggregate at the near surface depths; a hydrostatic hose connected to said hydrostatic actuation assembly for transmitting said hydrostatic pressure forces in said liquid; and a surface manifold assembly having a gauge coupled to said hydrostatic hose and providing visual readouts of said hydrostatic pressures, and an interface cylinder coupled to said hydrostatic hose and provided with an axially displaceable piston defining an interface chamber, said piston being connected to an electronic sensor to provide visual readouts representative of displacements caused by said downward forces at near surface depths in the soil/aggregate.