Mesostructural character and numerical simulation of mechanical properties of soil-rock mixtures

Soil-rock mixture is a kind of inhomogeneous material; for the difficulty of in-situ sampling and the underdevelopment of large-scale laboratory soil test, at present the study of the soil-rock mixture's mechanical properties is still at initial stage. With the quick development of digital image processing method, digital image processing has been successfully used in many kinds of fields. Based on the digital image processing, the microstructural model of soil-rock mixture by taking into account the actual material inhomogeneity is constructed. The structural character of the distribution of blocks is studied statistically; and it is shown that the confusion is only the external performance of the soil-rock mixtures. In fact, soil-rock mixtures have a good character of self-comparability in statistics. Using geometry transformation, the model of soil-rock mixtures under dual digital image has been translated into a document format which can be received by finite element software. By this step, the numerical simulation of actual microstructures of soil-rock mixture is carried out. The numerical simulation of the large-scale direct shear test indicates that the blocks obviously influence the stress field of soil-rock mixtures, and then influence the deformation and fracture type. Three kinds of possible failure propagation routes in soil-rock mixtures are put forward.