There are three phases of the deformation curve: (1) the re-establishing phase, from the origin to point A; (2) the pseudo-elastic phase, from point A to point B; and (3) the plastic phase, from point B to point C. After the borehole is drilled and the augers are withdrawn, the borehole walls relax, thus reducing the cavity volume. As the pressuremeter probe is initially inflated, the walls of the borehole are pushed back to their original position. Point A marks the point at which the volume of the borehole cavity has fully returned to its initial position, and is given the coordinates, , . The pseudo-elastic phase, the straight-line portion of the curve between points A and B, is dubbed so because of its resemblance to the elastic behavior of steel or concrete. Point B is the point

at which creep pressure has been reached, and is given the coordinates, , . The plastic phase begins at point B and extends to point C, which is asymptotic to the limit pressure. Point C, which is given the coordinates , , is defined as the point where the pressure remains constant despite increasing volume. The limit pressure is defined as the pressure required to expand the measuring cell by an amount beyond the volume required to inflate the pressuremeter and to push the borehole wall back to its original position ( ). The pressuremeter can be used to aid in the design of foundations for all types of soils, including residual soils. The settlements of foundations can be estimated using a deformation modulus, E , which can be derived from the pseudo-elastic phase (or straight-line portion) of the load deformation diagram.