A B C D E F G H I J K L M N O P Q R S T U V W X Y

O

one-dimensional compression
one-dimensional modulus (E'o, M)
open layer
optimum water content (wopt)
overburden stress (svo s'vo)
overconsolidated soil
overconsolidation ratio (Rm Rmp Ro Rp)

one-dimensional compression

Compression taking place with zero radial and horizontal strain.

one-dimensional modulus (E'o , M)

The ratio of the change in vertical effective stress to the change in vertical strain, when there is zero horizontal strain.
o (or M) = ds´a / dea
o = 1 / mv

open layer



A layer or stratum of soil from which porewater may drain both upward and downward into overlying and underlying permeable layers, thus enabling two-way drainage; drainage path length = half the layer thickness.

optimum water content (wopt)

The water content at which the maximum compacted dry density can obtained.

overburden stress (svo, s'vo)

(Also overburden pressure) The stress on a horizontal plane at a given depth due to the weight of overlying soil or rock.

overconsolidated soil

Soil having a current state which lies inside the normal compression line:
· current normal effective stress is less than current yield stress
· overconsolidation ratio Ro > 1
· generally: "current stress is less than maximum stress in the past"

overconsolidation ratio (Rm, Rmp, Ro, Rp)



The ratio of maximum past effective stress to the current effective stress.
Rm = s´m / s´A
Ro = s´y / s´A
Rmp = p´m / p´A
Rp = p´y / p´A