When the seepage pressure becomes equal to the pressure due to submerged weight of a soil, the effective pressure is reduced to zero and the soil particles have a tendency to move up in the direction of flow. This phenomenon is generally known

Soil mechanics is the theory of mechanical properties of soils. Foundation engineering - the theory of stability of foundations and construction methods used for their production. This also includes predicting the deformation of the substrate.

The objectives of soil mechanics are (1) to study the physical and mechanical properties of soil, (2) to apply this knowledge for the solution of practical engineering problems, and (3) to replace by scientific methods the empirical ones of design used in foundation and soil engineering in the past.