DYNAMIC COMPACTION OF LOOSE GRANULAR SOILS - EFFECT OF PRINT SPACING

A method is presented to evaluate the effect of print spacing on the d ynamic compaction of loose granular soils. It uses a recently develope d wave-equation model together with an approach to predict the lateral extent of soil improvement around the pounder. The procedure to evalu ate the effect of print spacing is demonstrated using two examples, wh ich show that the most critical areas are the center of the grid and t he middle of the side of the grid where the least improvement of soil is achieved. Three reported case histories of dynamic-compaction proje cts are analyzed, and the solutions are shown to be in good agreement with those obtained from the field. Two design curves, one for the cen ter of the grid and the other for the middle of the side of the grid, are established. These curves summarize the influence of print spacing on the effectiveness of dynamic compaction in densifying the soil at these two critical locations and are useful for the selection of print spacing in dynamic-compaction projects.