Determination of strength and index properties of fine-grained soils using a soil minipenetrometer

This paper describes the use of a soil minipenetrometer (SMP) to determine the strength and index properties of fine-grained soils. The SMP has been developed to allow both fall cone and quasi-static penetration tests to be performed. Displacement controlled quasi-static penetration tests can be used for the direct measurement of undrained shear strength, both for remolded and undisturbed samples. In addition the quasi-static penetration test can be used to define an additional lower plastic limit parameter, the PL100, which represents the moisture content of a fine-grained soil with an undrained strength 100 times that at the liquid limit. This approach offers the advantage that removal of the coarse fraction is not required to estimate the PL100.