What Does Cohesive Disturbed Sample Mean?
Cohesive disturbed samples refer to soil samples derived from test boreholes drilled using cable percussion boring. These cohesive soil samples are not intact or are disturbed. Usually soft and moderately stiff cohesive soils can be easily sampled without excessive disturbance.
Since most laboratory index testing methods do not require undisturbed samples, many geologists use disturbed soil samples that are easier to collect and are economical.
Trenchlesspedia Explains Cohesive Disturbed Sample
Cohesive soils are clayey or fine-grained soils with cohesive strength that binds the soil particles together. Cohesive soils can be easily molded, do not crumble and is plastic when moist.
Cohesive disturbed soil samples are collected using a split barrel sampler during a standard penetration test (SPT). These samples also give an indication of density and consistency that cannot be obtained while collecting undisturbed samples.
The disturbed soil samples, however, can only be used for shear strength testing after remolding and simulating in-situ conditions but cannot be used for consolidation testing.