DEVELOPMENT OF RANDOM MESOSTRUCTURE GENERATING SYSTEM OF SOIL-ROCK MIXTURE AND STUDY OF ITS MESOSTRUCTURAL MECHANICS BASED ON NUMERICAL TEST

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°-φs/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.