Multivariate distribution for undrained shear strengths under various test procedures

The undrained shear strength (s(u)) of a clay is not a constant. In particular, su values of a clay evaluated by different test procedures are different because these tests may have different stress states, stress histories, degrees of sampling disturbance, and strain rates. This study constructs the multivariate probability distribution of su from various test procedures based on a large clay database. This multivariate distribution provides an estimation of the normalized undrained shear strength based on four factors: test mode, overconsolidation ratio, strain rate, and plasticity. Once this multivariate distribution is constructed, interesting questions can be answered systematically using simple Bayesian analysis, e. g., given the su value for one test procedure, what is the updated mean and coefficient of variation of the su value for another test procedure?