STUDY ON THE ORIENTATION ANGLE OF ROCK LONG AXIS ON THE MACROMECHANICAL PROPERTIES OF SOIL-ROCK-MIXTURE

As a typical heterogeneous soil, the macro-mechanical behavior of soil-rock-mixture is related with rock meso-structure closely. Under applied loads, two kinds of load transfer mechanism, i.e., rock structure system and non-structural soil matrix system, were developed. From load transfer path and shear path, the structure effect of rocks were analyzed. Then, the influence of rock long axis angle on the shear strength is identified. By treating the soil-rock-mixture as a two-phase composite composing by rock block and soil, biaxial compression mesoscopic analysis models were established and validated. Then a series of numerical tests with different orientation angles of rock long axis were carried out. The influence of orientation angle of rock long axis on the macro-mechanical properties of soil-rock-mixture were discussed, including the deviator stress, internal friction angle, cohension. The analysis results indicate that with the increment of orientation angle of rock long axis from 0° to 90°, the deviator stress and strength parameters all decrease initially and then increase. The relationship between deviator stress and orientation angel of rock long axis can be described as a parabolic curve.