Experimental study on shear properties and resistivity change of soil-rock mixture.

The deterioration of shear resistance in rock and soil masses has resulted in numerous severe natural disasters, highlighting the significance of long-term monitoring for disaster prevention and mitigation. This study explores the use of a nondestructive method to quickly and accurately evaluate the shear properties of soil-rock mixture. The shear stress, shear strain, and resistivity of the soil-rock mixture were tested simultaneously using a combination of direct shear and resistivity tests. The test results show that the resistivity of the soil-rock mixture gradually decreases with increasing shear strain. The resistivity of all specimens ranged approximately from 60 to 130 Ω.m throughout the shear process. At the end of the shear test, the vertical failure resistivity showed an irregular "W" shape with increasing rock content. It exhibited a significant negative linear functional relationship with the shear strength. With reference to the determination of cohesion and internal friction angle on the shear strength envelope, the horizontal angle of the vertical failure resistivity-normal stress curve is defined as the resistivity angle, and the intercept of the curve is the resistivity at the initial moment of shear. It has been observed that the resistivity angle is negatively and linearly correlated with the internal friction angle. At the same time, there is a linear growth relationship between resistivity at the initial moment of shear and cohesion. It has been demonstrated that an increase in rock content contributes to a general escalation in both the average structure factor and average shape factor. Meanwhile, a decrease in the anisotropy coefficient has also been noted. These alterations are indicative of the extent of microstructural transformations occurring during the deformation process of the soil-rock mixture. The research results verify the feasibility of real-time deformation monitoring and characterization of shear strength parameters using resistivity. [ABSTRACT FROM AUTHOR]