Influence of fine-grained soil and loading rate on the mechanical behavior of soil rock mixtures

Soil-rock mixtures are widely used in engineering for filling and subgrade applications, with their mechanical behavior playing a critical role in the stability and safety of engineering structures. This study utilized two types of fine-grained soils, non-cohesive and cohesive, to construct the soil-rock mixtures with similar stone content; indoor triaxial tests were conducted to investigate the effects of fine-grained soil type and loading rate on the mechanical behavior of soil-rock mixtures. The results show that under drained conditions, the strength of the soil-rock mixture containing non-cohesive soil is higher than that of cohesive soil, while under undrained conditions, the strength of the soil-rock mixture containing cohesive soil is higher. Variations in loading rate significantly impacted the mechanical behavior of soil-rock mixtures, with faster loading rates causing more intense movement, rotation, and frequent damage to internal stone particles, ultimately influencing their macroscopic mechanical properties. This study provides valuable insights for the design and construction of soil-rock mixture engineering.