Permeability characteristics and empirical prediction of cementitious soil rock mixtures based on numerical experiments of mesostructure

Due to material composition and structure effects, the permeability characteristics of cementitious soil rock mixtures (CSRMs) significantly differ from homogeneous rock and soil mass, and the great discreteness in limited indoor or in-situ experimental data has always shown up. This study established the stochastic mesostructure models of CSRMs with a self-developed modeling technology. Their saturated and unsaturated seepage parameters were determined by laboratory tests. Then, saturated and unsaturated numerical seepage simulations of CSRMs were carried out. The influences of rock block content, occurrence, shape, and permeability difference in soil and rock mass on their permeability coefficient were investigated. The empirical permeability coefficient prediction formulas about influencing factors were discussed. The results showed that the seepage characteristics of CSRMs conformed to Darcy’s law. Their permeability coefficient decreased first and then increased with the rock block content, and they achieved the minimum value when it was about 40 %. Their permeability coefficient increased with the rock block inclination and decreased with the aspect ratio of rock blocks. When the difference of soil and rock mass in permeability coefficient exceeded 1 × 10³ in magnitude, their permeability coefficient should be mainly controlled by the side with the large permeability. Three empirical permeability prediction formulas for CSRMs were proposed. This study could provide theoretical and methodological references for the permeability cognition of CSRMs.