Large-scale in-situ test for mechanical characterization of soil–rock mixture used in an embankment dam

•S–RM obtained by mixing rock blocks to the cohesive soil is used for the first time as the core wall material of the Nuozhadu embankment dam.•The differences in the mechanical behavior of soil and S–RM are studied in here and a companion paper•The mixing of rock blocks changes the deformation behavior of the sample.•The existence of rock blocks improve the deformation modulus and the internal friction angle of S–RM.

To improve the mechanical behavior of core wall in higher embankment dams, soil–rock mixture obtained by mixing rock blocks to the cohesive soil is used for the first time as the core wall material of the Nuozhadu embankment dam, China. The differences in the mechanical behavior of soil and soil–rock mixture samples are studied in depth. Two large-scale compaction test fields and a series of in-situ direct shear tests have been conducted on soil and soil–rock mixture samples. The mixing of rock blocks changes the deformation behavior of the sample. The existence of rock blocks makes the deformation modulus and the internal friction angle of soil–rock mixture greater than that of the soil sample, while decreasing its cohesive force.