Experimental Study on Physical and Mechanical Properties of Mixed Filling behind Retaining Wall

Abstract

Through large-scale triaxial shear test and particle sieving test, the particle breakage characteristics and shear strength of mixed coarse-grained fillers behind a high filling wall in Guizhou Province were studied. The effects of mudstone content, particle gradation, relative density and stress state of coarse-grained mixed fillers on particle breakage and shear strength were analyzed. With the increase of mudstone content, gradation and relative density, the particle breakage rate decreases. With the increase of confining pressure and stress, the particle breakage rate of coarse-grained soil also increases. The shear strength cohesion increases first and then decreases with the increase of mudstone content, and the internal friction angle decreases gradually. With the improvement of particle size distribution and the increase of relative density, the cohesion and internal friction angle increase. At the same time, a multivariate non-linear regression model was established to synthesize the comprehensive internal friction angle. The predicted values were in agreement with the experimental data, and the optimum mixed packing parameters were selected.