中文摘要：

通过引进和开发二维颗粒流程序，基于相似理论建立了可以模拟砂土地基强夯加固的细观颗粒流模型，结合小比尺室内细观模型试验，从颗粒细观力学角度入手对干砂在强夯冲击加固过程中的动力反应特性进行了数值模拟。结果表明，数值模拟结果与试验结果有较好的一致性，利用颗粒流模型可以很好地模拟干砂在冲击荷载作用下的锤底动接触应力、颗粒间动接触应力和颗粒位移场分布情况，并可以实时跟踪颗粒的变位及接触应力变化，实现从细观角度揭示干砂强夯动力响应特性，研究工作为今后砂土强夯加固宏细观机制研究提供了一条新的思路。

英文摘要：

Based on the similarity theory, the numerical analysis model is established to study the mechanism of dynamic compaction of dry sands by means of secondary exploitation using the PFC^2D （particle flow code in 2 dimensions）. Dynamic response characteristics of dry sands to impacting are simulated in combination with laboratory mesomechanical model test. The availability and rationality of the proposed numerical method is verified by comparing the numerical solutions with the results of real data. The results show that the dynamic stress of tamper bottom can be well simulated with PFC^2D as well as dynamic stress among sand grains and displacement field during dynamic compaction. Apart from movement of sand grains, the change of dynamic stress can be real-time traced and recorded. The findings of this study provide a new route to research the macro-meso mechanism of sands dynamic compaction.