Abstract:In order to obtain the dynamic compaction characteristics of Leipzig sandy soil foundation in Germany, a self-designed model test device and measurement system were adopted. Three different relative density of sand were prepared for dynamic compaction in the laboratory model tests, each group of test was carried out with 24 tamping times. During the dynamic compaction, the velocity, displacement, dynamic force and energy release duration of tampings were measured. PIV (particle image velocimetry) technology was adopted to investigate the sand particles displacement after the dynamic compaction, and the development characteristics of effective reinforcement area in horizontal direction and depth direction were obtained. The results show that the velocity-time curves of the 6th, 12th, 18th and 24th tampings are basically coincidence with each others in the rapid declining stage. When the higher tamping times achieved, the rebound velocity will be higher with shorter duration, which reflecting the different energy release duration. For ID0.4, ID0.5, and ID0.7, the energy release duration decreases by 38.9%, 34.7% and 31.4%, respectively, from the 6th to the 24th tampings; while the resilience ratio of the tamp in the 24th tamping reaches to 65.3%, 67.1% and 69.0%, respectively. The higher the relative density of the sand, the greater the impact force of tamp, and the smaller the differences between the 6th, 12th, 18th and 24th tampings. With the increase of the tamping times, the peak value of dynamic force gradually increases, the slope of upward curves become smaller, and the impact duration are gradually shorter. For ID0.4, ID0.5 and ID0.7, after the 20th, 18th and 15th tampings, respectively, the effective reinforcement area in horizontal direction increases more than in depth direction.