A Systematic Method to Evaluate the Shear Properties of Soil-Rock Mixture considering the Rock Size Effect

Abstract

The soil-rock mixture (S-RM) is widely applied in the geotechnical engineering due to its better mechanical properties. The shear strength, an essential aspect of S-RM which governs the stability and the deformation, is rather necessary to be revealed properly. The extraordinary issue of S-RM compared to fine-grained soils is the grain size effect on the strength analysis. This paper proposes a systematic method to obtain the realistic shear strength of S-RM by detecting the rock size effect. Firstly, based on fractal theory, the rock size was determined as 5 mm by the multifractal property of granular size distribution. Then, based on 2 selected specimen sizes combining the engineering dimension, shear gaps (T) effect and specimen size effect on the shear strength of S-RM have been investigated. It is shown that the gap of the direct shear test decides the physical mechanism of particles forming the shear resistance of S-RM based on the variation of apparent cohesion and mobilized internal friction angle. Specimen size effect is weakened by the gap effect considering the boundary effect. Realistic and stable shear strength parameters of S-RM have been researched by a reasonable gap (0.2–0.4D, where D is the largest particle size).

Experimental Research on Shear Strength Characteristics of Soil-Rock Mixtures

“…On this basis, the effects of engineering size, shear gap effect and sample size on the shear strength of S-RM were studied. The results show that the physical mechanism of S-RM shear resistance based on the change of apparent cohesion and internal friction angle of particles is decided by the clearance of direct shear test [28]. In general, the mechanical behaviour of S-RM mainly depends on the deformation rate, water content and particle size.…”

The Influence of the Number of Joints on the Size Effect of Shear Strength and Characteristic Strength

“…e size e ect of rock shear strength has been consistently the focus of domestic and foreign research. For example, Ren et al [3] proposed a systematic method to obtain the actual shear strength of soil-rock mixture (S-RM) by detecting the e ect of rock size. Scholars used the Particle Flow Code (PFC) software to study the size e ect of shear strength.…”

Experimental Study on Shear Failure Mechanism and the Identification of Strength Characteristics of the Soil‐Rock Mixture

“…Han et al [18] obtained the unconfined compression strength of the SRM by using a bearing capacity experiment and the creep laws of the SRM by using compressive creep experiments. Ren et al [19] evaluated the shear properties of soil-rock mixture considering the rock size effect by a systematic method.…”