SOA: Large Strain Consolidation Predictions

Large deformation consolidation computer programs are being used extensively by Florida phosphate mining industries for compliance with regulatory activities. Accordingly, a prediction symposium was held to provide a forum of idealized boundary conditions that would demonstrate areas of agreement and the limitations of various computer programs. Nine different program users provided predictions of pond elevation histories and of pore pressure and void ratio profiles after one year for four different waste clay disposal scenarios. Programs to estimate quiescent consolidation of waste ponds having uniform initial void ratios, with or without surcharge loading, and continuous and/or stage filling are available, but less available are programs that handle nonuniform void ratios and/or multilayer conditions with different nonlinear compressibility properties. Presently, piecewise linear programs appear best suited to accommodate the latter. In general, final height predictions for all scenarios were in agreement, but height predictions at early times were found sensitive to program input (i.e., number of time steps or layers). Agreement among void ratio and pore pressure profiles generally improved with depth. Least agreement was for stage filling and nonuniform initial void ratio and multilayer conditions.