A new strategy for improving the anti-dispersal properties and mechanical performance of dispersed soil in seasonal frozen regions: Research on the application of soybean urease-induced carbonate precipitation (SICP)

Abstract

Dispersive soils are extensively distributed across the Songnen Plain, Northeast China. These soils exhibit poor resistance to water erosion, and their engineering properties deteriorate significantly under seasonal freeze-thaw cycles, thereby posing severe geotechnical hazards. Conventional chemical stabilization methods suffer from issues such as ecological pollution and unsatisfactory long-term effectiveness, making it difficult to meet requirements for ecological compatibility and long-term stability. Soybean urease-induced calcium carbonate precipitation (SICP), an emerging, economical, environmentally friendly, and sustainable technique, effectively inhibits soil dispersion and enhances freeze-thaw resistance by inducing calcium carbonate deposition to cement soil particles. In this study, a series of macro- and micro-scale tests were conducted to systematically evaluate the effectiveness of SICP in stabilizing dispersive soils and its long-term performance under freeze-thaw cycling. The corresponding stabilization mechanism and freeze–thaw deterioration mechanism were elucidated. Results show that SICP reduces interparticle repulsive forces and strengthens interparticle bonding through ion exchange and biomineralization-driven cementation, significantly improving the anti-dispersion capacity and mechanical properties of dispersive soils, the maximum unconfined compressive strength increase reaches 154.55%. Moreover, SICP effectively suppresses soil particle dispersion during freeze-thaw cycling and inhibits the formation and expansion of internal large pores (4-40 μm) and ultra-large pores (> 40 μm). After 30 freeze–thaw cycles, the strength of SICP-treated soil is 271.34% higher than that of untreated soil, indicating a fundamental enhancement in freeze-thaw resistance.