APPLICATION OF BOUNDING SURFACE PLASTICITY TO CYCLIC SAND BEHAVIOR.

The liquefaction of saturated loose sands became a major concern to civil engineers when it caused the failures of slopes, bulkheads, and buildings during the 1964 earthquakes at Niigata, Japan, and at Anchorage, Alaska. Since then, substantial efforts have been made to develop constitutive models which simulate the nonlinear soil behavior responsible for these catastrophes. This report presents a simplified version of the sand model, which has only eight material constants, all related to the physical sand properties observed in laboratory. The first section of this report summarizes the fundamental concepts of bounding surface plasticity, and emphasizes its features relevant to cyclic loading. The general presentation of the theory leads naturally into the second section where the model is introduced. The developed model can be used to simulate the liquefaction and compaction of sands in dynamic analysis.