Civil and Building Engineering.

Several parts of the analysis must be altered to conform to the methods normally used in engineering practice. First, the - curve is not plotted in the conventional manner but rather is rotated, as shown in Figure 3.18, because then the strain scale reads in the same direction in which settlement occurs.
Furthermore, it is common practice to plot on a logarithmic scale as shown in Figure 3.19.
The strain caused by the loading is ƒ 0, so equations from Eqs. 3.68 and 3.66 on the settlement of a layer j with thickness H can be computed using
A soil that has been deposited from suspension and consolidated to some stress, clearly the maximum stress to which the soil has ever been subjected, is said to be normally consolidated, and the associated – relationship is termed the virgin consolidation curve.
Compression of a soil causes largely irreversible movements between par- ticles, so if the soil is unloaded, the resulting rebound curve, or swelling curve, has a flatter slope than the virgin curve and the recompression curve (also called the reloading curve) forms a hysteresis loop with the rebound curve.
Soils now existing under effective stresses smaller than the maximum effective stress at some time in the past are said to be overconsolidated.
If the soil is undergoing consolidation down the virgin curve, it is under- consolidated. Obviously, this is a transient condition unless deposition of sediment is occurring at a fast enough rate that the excess porewater pressures cannot be dissipated.
The samples tested for Figure 3.20 started as a slurry, and the strain is calculated using the initial height of the unconsolidated slurry.