Soil-rock aggregate mixture is one type of non-homogeneous dispersion material mixed by rock and soil.Its shear strength is mainly affected by the moisture content

rock content

particle gradation and the degree of compaction

etc.On the basis of previous studies and the lab large-scale direct shear tests

this study considers the effect of gradation parameters

attains the required degree of compaction level by controlling the quality and volume of samples

and analyzes the influence of the main parameters on the shear strength.The results show that

in well-graded case

as nonuniformity coefficient increases

the shear strength increases first and then decreases

and achieved peak when the coefficient is around 22.99

while little impact by the coefficient of curvature.The shear strength of soil-rock aggregate mixture increases with the increasing rock content and compaction degree respectively

but the increases less when the degree of compaction is more than 92.5%.The shear strength decreases after the first increase with the increasing moisture content

and peaks at near optimum moisture content.Based on the Matlab’ multivariate linear regression analysis

the order of primary and secondary influencing factors on the shear strength is rock content > moisture content> degree of compaction > nonuniformity coefficient > coefficient of curvature.Through the regression analysis of test results

fitting formulas of it’s shear strength are obtained with correlation index R

2

bigger than 0.9.