Influence of matrix materials on the stability of weakly layered rock slopes

Abstract

In this study, a novel matrix material was developed by blending powdery clay (PC) with varying proportions of diatomaceous earth (DE) and straw, aiming to enhance the mechanical stability and ability of the water cycle of the materials. The unconsolidated-undrained triaxial, compaction, and infiltration tests were conducted to assess the mechanical characteristics of PC containing different ratios of DE and straw. The findings revealed that the addition of straw and DE enhanced soil permeability, as their quantities increased. However, when both DE and straw were mixed with the matrix soil at similar content levels, a decrease in the permeability coefficient was observed. Additionally, the results indicated a decrease in maximum compacted density with an increase in the proportions of straw and DE. When the straw content was below 50% and the DE content was below 40%, a rapid decrease in density was observed. In contrast, when the straw content exceeded 50% and the DE content exceeded 40%, the rate of density reduction decreased. Considering water cycle and mechanical stability comprehensively, the optimal soil matrix ratios are recommended as 50% PC, 40% DE content, and 10% straw. At this ratio, the cohesion specimen reaches its maximum value at approximately 42.83 kPa. Therefore, the appropriate selection of matrix materials in slope projects can enhance drainage performance, shearing strength, and slope stability, effectively reducing the likelihood of slope disasters.