A new macro- and micro- coupling model of barrier dam soil

Barrier dams are widely distributed worldwide. It is highly important to accurately evaluate the safety and emergency response of barrier dams. However, the stress-strain relationship of barrier dam soil, which is an important issue for the safety evaluation of barrier dams, has not been elucidated clearly because of its complex composition and wide particle gradation. Based on the proposed macro- and micro- coupling modeling scheme, a series of CT triaxial tests were carried out on barrier dam soil to observe the macroscopic and microscopic behavior. Based on the particle displacement distribution, a fabric evolution rate was proposed as an index to describe the evolution of fabric behaviors. A significant correlation was detected between the shear band fabric evolution rate and the macroscopic mechanical properties of the soil. The fabric evolution equation, modulus evolution equation and Poisson's ratio evolution equation were proposed to set up a new macro- and microcoupling model for barrier dam soil. The model has only five parameters that have definite physical meanings and can be easily determined by a series of triaxial tests. The validity of the proposed model was verified by different types of tests of barrier dam soil and soil-rock mixtures. The model can reasonably describe the fundamental properties of barrier dam soil with wide particle gradation. The proposed model established by macro- and micro- coupling modeling considers the relationship between macroscopic mechanical properties and microscopic fabric behavior, which is suitable for barrier dam soils with wide particle gradations.