Evolution of geotechnical soil testing II. Laboratory tests

Part I of this series discusses physical tests that are conducted in situ in the field and for the most part are empirical and intended for site evaluations. There also is a trend towards more direct measurement of fundamental soil properties in the field. The present paper describes a progression of physical tests that normally are performed in the laboratory and generally are more targeted and less dependent on empirical correlations. Bilinear shear envelopes that have been overlooked or bypassed in the past reveal new applications for shear and unconfined compression tests in relation to preconsolidation pressures that are relevant to foundation settlement. Factors influencing test reliability and required numbers of tests for statistical confidence also are discussed.