Experimental Study on Strength Properties of MICP-Treated Silty Sand

Microbially induced carbonate precipitation (MICP) using ureolytic bacteria has emerged as a promising technique for geotechnical applications, including soil stabilization, land remediation, and groundwater control. This bio-mediated process relies on urease activity to hydrolyze urea, leading to calcium carbonate precipitation, which enhances soil strength and stiffness. In this study, the mechanical behavior of silica sand treated with MICP was investigated under varying cementation concentrations (µ) (۰.۲۵–۱ mol/L), cementation ratios (β) (۱۰–۹۰%), and injection cycles (۳, ۱۴, and ۲۱). Key parameters evaluated included unconfined compressive strength (UCS), secant modulus (E۵۰), and calcium carbonate content. The results demonstrated a significant correlation between calcite content and mechanical properties, with optimal performance observed at ۱۴.۹۸% calcite content. This configuration yielded a UCS of ۱۰۳۰ kPa and an E۵۰ of ۳۸۹ MPa, achieved using Sporosarcina pasteurii, a β = ۵۰%, and a µ = ۰.۷۵ mol/L over ۲۱ days. Findings highlight the critical role of injection cycles and cementation concentration in achieving uniform calcium carbonate distribution and enhancing soil behavior. This study underscores the potential of MICP for tailored geotechnical solutions, providing valuable insights into optimizing bio-cementation processes.

کلیدواژه ها:

MICP treatment ، Sporosarcina pasteurii ، Soil biological treatment ، Unconfined compressive strength