Abstract: This study conducted a series of indoor and outdoor tests on Quelo sand in Angola, which has the characteristics of water softening and collapsibility. Four combination schemes with different levels of tamping energy(1 000, 2 000 kN·m) and different working conditions(natural, optimal moisture content) are adopted to carry out comparative consolidation tests. The variation rules of dry density, void ratio, heavy dynamic penetration number DPT(N63.5) and collapsibility coefficient of Quelo sand before and after dynamic compaction are analyzed. Furthermore, Suggested values of the impact depth, the effective reinforcement depth and the correction coefficient α of Quelo sand are proposed under different dynamic compaction programs. The experimental results show that although the physical mechanics indexes of Quelo sand can be significantly improved with the lower tamping energy level under the condition of humidification; however, its collapsibility can not eliminated obviously. Only when the tamping energy is high enough, the collapsibility of Quelo sand can be further eliminated. And there is a threshold of tamping energy in the dynamic compaction for eliminating the collapsibility of Quelo sand under humidification conditions.

Key words: Quelo sand, dynamic compaction, collapsibility, reinforcement depth