Undrained shear strength of fine soils

Undrained shear strength of clays

cu (kPa)

Extremely low

< 10

Very low

10 to 20

Low

20 to 40

Medium

40 to 75

High

75 to 150

Very high

150 to 300

Extremely high*

> 300

*Materials with shear strength greater than 300 kPa may behave as weak rocks and should be described as rocks according to ISO 14689-1