A Method for Estimating the Excavatability of Caliche
A simple method for classifying caliche with respect to excavatability is presented. The method is based on the results of a laboratory testing program from which two empirical equations were derived, one relating seismic velocity to size-corrected point load strength index, the other relating seismic velocity to a newly proposed parameter, the comminuted uniformity coefficient. The effect of carbonate content also was investigated, but no correlation between carbonate content and either point load strength or comminuted uniformity coefficient could be established. The excavatability of the caliche is determined from the seismic velocity by the empirical correlations between seismic velocity and ease of excavation established by excavation equipment manufacturers. The results of this study were applied successfully to a number of excavations in caliche in Tucson, AZ.