Abstract: Based on compaction test of different gradations and different moisture contents of coarse-grained soils, the compaction characteristics and fractal feature of coarse-grained soils are studied. The results show that the maximum dry density of coarse-grained soils would increase with the increase of coarse grained content in gradation. The maximum dry density reach the maximum value as the coarse grained content is 70%; while it would decrease with the increase of coarse grained content in gradation as the content is more than 70%. The particle size distribution of crushing granular has a good fractal feature. The crushing fractal dimensions are between 2.279 0－2.892 2; higher than that before test. Under the same gradation condition, the crushing fractal dimension of coarse-grained soils increased with moisture content. The increase amplitude is obvious when P5 is larger than 50%. A good linear regression relation exists between crushing fractal dimensions D and broken rate Bg. Difference value of the granularity fractal dimension before and after compaction can show the crushing degree of coarse-grained soils objectively. Coarse grained content and moisture content are two key factors affected on particle breakage; but the influence of coarse grained content is more obvious.

Key words: coarse-grained soils, compaction test, moisture content, coarse grained content, fractal, particle breakage