A prediction method for the uniaxial compressive strength of the soil-rock mixture considering the effect of the particle size

Abstract

Abstract The reasonable prediction of mechanical parameters of the soil-rock mixture (S-RM) is crucial to build an engineering structure on the deposit slope. As a typical multiphase geomaterial, the emergence of rock blocks of various sizes destroys the integrity of the soil matrix and results in the complex and varied mechanical properties because of its interaction with the soil matrix. Because of the size effect, which is caused by the size restriction of traditional test apparatus, it is more challenging to measure the precise mechanical parameters of S-RM. This study proposed an approach to predicting the uniaxial compressive strength (UCS) of S-RM taking the particle size effect into account. The impact of the particle size on the mechanical behaviors of S-RM under various volumetric rock block proportion (VBP) conditions was discussed using the particle flow discrete element method from both a macroscopic and mesoscopic view. The parameter “Am” was used to describe the decreasing rate of UCS with various VBPs, and a quantitative description to predict the parameter “Am” of S-RM with various maximum particle sizes was proposed. A method to predict the UCS value of S-RM with various VBPs was conducted while taking the influence of size effect into account using the parameter “Am” and the UCS of the soil matrix.