Liquefaction and Residual Strength of Loose Sands from Drained Triaxial Tests

Report No. CCEER-94-4The proposed method of effective stress evaluation of monotonic undrained stress-strain and stress path behavior based upon the use of consolidated rebounded drained triaxial tests with volume change measurements is a straight forward and powerful approach to understanding the liquefaction behavior of loose sands. Based upon this approach and the fact that the resulting rebounded drained volume change curves display essentially the same shape, a number of important distinctions result, i.e., the associated shape of the drained volume change curves for complete liquefaction, the relationship between the steady state and critical state conditions, the relationship between the drained and the undrained effective stress friction angles, the conditions of the peak undrained strength (i.e. the product of the stress level and effective confining pressure) , etc. In addition, commercial geotechnical labs can readily apply the proposed approach. Chapter 2 of the report provided the methodology and demonstrated the validity of the approach via four test series. Chapter 3 dealt with the particular condition that leads to the undrained peak resistance and provided a method by which it could be assessed from the results of a single drained tested. Chapter 4 provided the start of a drained test database that, with additions, will supply the means for assessing undrained behavior based solely upon classifying the sand of interest