Lateral Earth Pressure and Design of Retaining Structures

Abstract

The pressure in the pore water in a fully saturated soil is hydrostatic, i.e. u_H = u_V = u so there is only one value. The pressure within the mineral grain structure (effective stress) is not the same in all directions. The vertical effective stress in a soil can be obtained from simple considerations of depth multiplied by the bulk or submerged unit weight and is treated as a principal stress, σ_V′. For the design of vertical walls the horizontal stress acting σ_H′ is required and a coefficient of earth pressure, K is used to relate the two stresses:

$$K = \frac{{{\sigma _{\text{H}}}^\prime }}{{{\sigma _{\text{V}}}^\prime }}$$

(11.1)