In this study, we analyzed the settlement characteristics of rockfill embankments mixed with soil by confirming the physical  properties  of  soil  materials  mixed  with  silty  materials  and  analyzing  the  compression  characteristics  of  gravel  materials according  to  the  mixing  ratio  of  soil  materials.  For  this,  we  mixed  silty  materials  into  sandy  soil  to  analyze  the  compression characteristics of soil materials, and we constructed a foundation by mixing various ratios of soil into rockfill materials with a particle distribution similar to that of river gravel, and conducted a one-dimensional compression experiment using a medium-sized chamber. As a result of the experiment, in the case of mixed soil materials, the Transition Fine Content (TFC) appeared in the range of 21~26%  depending on the load condition, and in the case of rockfill materials mixed with soil, as the void filling ratio of soil in gravel samples increased, both total compression and creep compression decreased, but after a 50% mixing ratio, the settlement amount increased again.