Abstract: The original foundation of the Urumqi Airport flight area project site is distributed with a 0~4 m thick layer of low moisture silt soil, which has collapsibility. In-situ dynamic compaction treatment at two energy levels of 2 000 and 3 000 kN·m for collapsible loess foundation was conducted, the settlement was systematically monitored during the dynamic compaction process, and the physical and mechanical properties of the foundation soil and standard penetration test data were tested before and after treatment. The effect of dynamic compaction method on treating collapsible loess foundation was analyzed, and recommended design parameters and detection indicators for dynamic compaction treatment were proposed. The results show that the dynamic compaction method can effectively eliminate the collapsibility of low moisture content collapsible loess in the area, significantly improve its compactness and bearing capacity, and meet the post construction settlement control requirements of the airport flight zone after treatment. The collapsibility coefficient should be a mandatory inspection item, and it should be required that the collapsibility coefficient after dynamic compaction be less than 0.015. Pore ratio, dry density, and standard penetration can be used as effective detection indicators for dynamic compaction treatment.

Key words: high fill airport, collapsible silt, dynamic compaction method, detection method