Study on scale effect and particle crushing characteristics of continuously graded coarse-grained soil

The scale effect is an inevitable engineering challenge in dam construction, and the scale test is an effective means to characterize the dam material properties. In this article, the scale effect of the large coarse-grained soil is investigated based on physical and numerical tests. Firstly, the indoor and field compression test apparatuses are optimized to rectify the effect of barrel sidewall friction on the compressibility modulus during the tests. Then, the sample preparation standard for different scaled samples is determined by large-scale relative density tests in the field. Finally, based on indoor and field large-scale compression tests, the variation of the scale effect is investigated, and the particle crushing characteristics of the continuously graded aggregate sample are analyzed. The crushing characteristics of the continuously graded aggregate sample differ from those of the single-particle and the single size-group aggregate sample (a small range of particle sizes). Compression tests of the single-particle, single size-group aggregate, and continuously graded aggregate sample are characterized by overall splitting, overall splitting and local crushing, and local or angular crushing, respectively. The coordination number is the main reason for the difference in crushing characteristics of different test samples. The relationship between different particle sizes and strengths of continuously graded aggregate sample is investigated. The results of the study can provide a reference for recognizing the scale effect of large coarse-grained soils and evaluating compaction quality in the field.