| Based on the project on expressway in Dayu Sichuan province, the compacting technology of typical compacting methods such as vibrating compaction, impactive compcation and dynamic compaction are studied by field tests. And the influnce of degree of compaction and compacting methods on the settlement is analyzed also.For the vibrating compaction, the degree of compaction decreases with the increasing of the thickness of rolled layer, but the amplitude is very small. The degree of compaction increases when the number of roller passes increases. When the number is bigger than 6, the amplitude of increasing becomes small. The thickness of roller layer is proposed to be 40～50cm, and the number of roller passes is proposed to be 6～8. For the dynamic compaction, the compacting settlement stablizes with the increasing of number of dynamic compaction. When the compactive effort is 1000kN · m or 600kN · m, the optimum number of dynamic compaction is 6 and the average compactive settlement of subgrade is 30～40cm. As a result using the criteria that the minimum number of dynamic compaction is 6 and the settlement difference is smaller than 5cm is suitable. Comparising with vibrating compaction higer compactive capacity and degree of compaction can be gotten by using daynamic compaction. Dynamic compaction is suitable to the fill embankment Using deflection to evaluate the result of the dynamic compaction is not suitable. Impactive compaction can increase the degree of compaction in the subgrade. The suitable number of impactive compcation is proposed to be 20.The analysis of settlement of subgrade indacaties that the settlement is smaller when the degreee of compaction is higher and properly choosing filling may decrease the settlement of embankment. Dynamic compaction in multi-layer can increase the whole degree of compaction of the embankment, and minish the settlement. This method is more economical. At last, the methods that decrease the settlement after construction are proposed by comparison.
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