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Structural Monitoring and Maintenance Volume 11, Number 3, September 2024 (Special Issue) pages 187-202 DOI: https://doi.org/10.12989/smm.2024.11.3.187 |
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Comparative study of calcium carbonate deposition induced by microorganisms and plant ureases in fortified peat soils |
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Chao Wang, Jianbin Xie, Yinlei Sun, Jianjun Li, Jie Li and Ronggu Jia
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| Abstract | ||
| For the problems of high compressibility and low strength of peat soil formed by lake-phase deposition in Dianchi Lake, microbial-induced calcium carbonate deposition (MICP), phyto-urease-induced calcium carbonate deposition (EICP) and phyto-urease-induced calcium carbonate deposition combined with lignin (EICP combined with lignin) were used to reinforce the peat soil, the changes in mechanical properties of the soil before and after the reinforcement of the peat soil were experimentally investigated, and the effect and mechanism of peat soil reinforcing by the three reinforcing techniques were tested and analyzed using X-ray diffraction (XRD) and scanning electron microscope (SEM). The results show that: compared to the unreinforced remolded peat soil specimens, the unconfined compressive strength (UCS), cohesion and internal friction angle of the specimens reinforced by MICP, EICP and EICP combined with lignin techniques have been greatly improved, and the permeability resistance has been improved by two, two and three orders of magnitude, respectively; the different methods of reinforcing generate different calcium carbonate crystalline phases, with the EICP combined with lignin technique generating the most stable calcite, and the MICP and EICP techniques generating a mixed phase of calcite and spherulitic chalcocite. Analyses showed that for peat soil reinforcement, the acidic environment of peat soil inhibited the growth and reproduction of bacteria, EICP technology was superior to MICP technology, and the addition of lignin solved the defect of the EICP technology that did not have a "nucleation sit", so EICP combined with lignin reinforcement was preferred for the improvement of peat soil. | ||
| Key Words | ||
| EICP; EICP combined lignin; MICP; reinforcement mechanism; the peat soil | ||
| Address | ||
| Chao Wang, Jianbin Xie, Yinlei Sun, Jianjun Li and Jie Li: School of Architecture and Planning, Yunnan University, Kunming 650500, P.R. China Ronggu Jia: Construction and Investment Holding Group No.1 Engineering Survey and Design Co., Ltd., Kunming 650500, P.R. China | ||
