Influence of different particle size and rock block proportion on microbial solidified soil-rock mixture

Abstract

This paper takes soil-rock mixture as the research object, and focuses on the application of mechanical properties of soil-rock mixture improved by microbial mineralization under the influence of different factors. In this paper, the prepared bacterial liquid and cementation reagent are used to mix the bacterial liquid and cementation reagent in the soil-rock mixture under different proportions，using the unconfined compressive strength test to find the optimal ratio of soil-rock consolidation, the microbial mineralization and cementation ability and physical and mechanical properties of soil-rock mixture under the influence of rock block proportion and particle size were discussed. The results show that the soil-rock mixture is not a uniform carrier of the medium, and the force on the surface of the sample is not uniform, with the increase of stress load, the stress-strain curve shows a sawtooth upward trend, peak value, etc.; the microbial cemented soil-rock mixture with the particle size of 0.2-0.4cm and 0.4-0.6cm under the rock block proportion of 50%, the unconfined compressive strength of the microbial cemented soil-rock mixture with a rock particle size of 0.6-0.9 cm reaches the highest at 60% rock block proportion ; when the stone content is 20%-50%, the unconfined compressive strength decreases with the increase of particle size; when the stone content is 60%, the value of unconfined compressive strength first decreases and then increases with the increase of particle size; both SEM and XRD test results proved that Sporosarcina pasteurii could effectively induce the formation of calcium carbonate, and crystallizes at the pores of the particles to improve the mechanical properties of the soil.