New Method to Evaluate Strengthen Efficiency by Dynamic Compaction

The tamping energy or tamping momentum usually is adopted to evaluate the efficiency of dynamic compaction (DC), meaning that the same tamping energy or tamping momentum leads to the same strengthening effect to the soil. This paper presented some new findings from field monitoring and numerical simulation of DC of granular soil. The phenomenon of particle breakage was taken into account for both large-scale field tests and the numerical study. A series of large-scale DC field tests was conducted with nine different combinations of hammer weight (M) and drop height (H). The results showed that neither tamping energy nor tamping momentum controls the efficiency of dynamic compaction, which leads to overestimation the contribution of drop height. The findings were confirmed by numerical results in which the quantity MH alpha was kept constant and alpha was varied. It was found that the same compaction efficiency can be obtained when alpha is about 0.2. A parameter alpha is recommended to balance the contribution ratio of M to H. The findings from this study may benefit the engineering application and further research of DC.