Research progress on static properties and laboratory testing technology of coarse-grained soil

Coarse-grained soil is a widely used soil material, which has the characteristics of easily broken particles, and the research on its mechanical properties and laboratory testing technology is of great importance. The static properties research progress of laboratory testing technology of coarse-grained soil are summarized, and the static properties including particle breaking rule, critical state, dilatancy characteristics, and the law of the scale effect. The analysis shows that particle breakage and the scale effect will significantly affect the mechanical properties of coarse grained soil, and there are still differences in the understanding of critical state and dilation characteristics. In terms of the laboratory testing technology, in order to increase the tested particle size, and reduce the influence of the scale effect, many kinds of large and ultra-large laboratory test instruments have been used, which can carry out the test under wider gradation, complex conditions of high stress state, variety of complex stress path, wind erosion degradation, coupled thermal-hydro-mechanical and etc. To explore the mechanical properties of coarse-grained soil under complex conditions has become the new research spot. On this basis, four suggestions and prospects are put forward for the research problems and directions of coarse-grained soil. © 2020, Science Press. All right reserved.