Abstract: Using the MTS816.03 test system and self-designed compression apparatus for broken rocks, the compaction tests for saturated broken rocks with different lithologic have been conducted, and the influence of lithology, axial stress, initial gradations and loading rate on compaction deformation and fractal characteristics has been analyzed. The results have shown that：1) The compaction processes of gangue, mudstone and sandstone are similar and can be divided into two stages, including the rapid compaction deformation stage (0-4 MPa) and the slow compaction deformation stage (after 4 MPa). However, the compaction deformation rate of limestone is steady. 2) Under the same initial gradation, as axial stress increases, the fractal dimension of sandstone samples increases monotonously, and the breaking degree gets higher. The relations between fractal dimension and axial stress can be described by exponential function. 3) In the compacting process, as the Talbol exponent increases, the axial displacement increases. As the loading rate increases, the axial displacement decreases. 4) Under the same axial stress, 12 MPa, as the Talbol exponent increases, the increment of fractal dimension increases and the quantity of rock particles crushed increases. As the loading rate increases, the fractal dimension decreases, and the breaking degree gets lower.

Key words: initial gradation, saturated broken rocks, compaction deformation, fractal dimension