Development of random mesostructure generating system of soil-rock mixture and study of its mesostructural mechanics based on numerical test

Abstract

The mesostructure characteristics significantly affect meso-failure evolution mechanism and the macro-mechanical characteristics of soil-rock mixture (S-RM) under external forces. It is very important for the improvement of theoretical system of S-RM mechanics to study the mesostructural mechanics of S-RM based on its mesostructural characteristics. Accordingly, the statistics, geometry, random simulation techniques, etc. are used, and the random mesostructure generation system of S-RM based on arbitrary polygonal and elliptic rock blocks(R-SRM2D) has been developed. Based on R-SRM2D, a series of random S-RM samples with different rock block contents, granularity compositions, rock block spatial distributions and soil-rock interfaces are generated, which is used to study the relationship between mesostructure difference and meso-failure mechanics or macro- mechanical characteristics of S-RM by numerical test. Meaningful results have been obtained theoretically. It is indicated that with the increment of rock block content, the elastic modulus and uniaxial compressive strength of S-RM increase; at a certain rock block content, the macro-strength of S-RM decreases with the increment of rock block fractal dimension; the compressive strength of S-RM reaches maximum value when the longer axis of rock blocks is perpendicular or parallel to the principal stress axis; when the angle between the longer axis of rock blocks and the principal stress axis is equal to (45°-ψS/2), the compressive strength of S-RM reaches minimum value; the cementation action of soil-rock interface makes the macro-strength of S-RM increases obviously, whose uniaxial compressive strength increases nearly twice.