Although conventional improved soil using cement has high strength, a maximum strength can be induced by a small strain, causing cracks. Thus, such improved soil is not considered to be fit for core materials (i.e., impervious materials) for earth dam embankments. We have developed a method to repair embankments with crushed and compacted soil utilizing earth dam mud soil. This method enables embankments which rarely crack to be constructed. The improved soil was produced in the following manner. First, the stabilized soil was cured for a few days. The soil was then crushed, plowed, compacted, and re-stabilized, resulting in an improved soil that, although it had lower strength, at the maximum strength can only be generated by a large strain. In this paper, mechanical tests for soil specimens prepared in a laboratory and obtained from actual embankments were used to obtain the curing times till crushing, and the strength and deformation characteristics of the crushed-compacted soil. In addition, we carried out a dry-wet cycling test for endurance for the crushed-compacted soil, and examined the mechanical characteristics. Finally, we describe some actual examples where the present method has been applied.