Study on migration and diffusion law of MICP solution in fractured loess

Abstract

In this paper, according to the migration and diffusion law of MICP solution in fracture-pore medium, the migration and diffusion equation of MICP solution in loess fracture-pore medium was derived first. Then, the migration and diffusion test was carried out by using the self-made Mdevice. In the model, the apertures of the fracture of 0.5 mm, 1.0 mm and 1.5 mm were selected, and the calcium ion concentrations at different points were measured by atomic absorption method, to obtain the distribution map of calcium ion concentration. According to the test results, the migration speed of calcium ions in the direction along the fracture is less than the diffusion speed of the wet peak, and the vertical fracture direction is faster than the diffusion speed of the wet peak. The distribution range of calcium ion concentration increases first and then decreases with the increase in fracture opening. COMSOL was used to compile the mathematical equation, and the whole process of MICP solution migration and diffusion was numerically simulated. The numerical calculation results are basically consistent with the experimental results, and the derived mathematical equation is reasonable.

Keywords

Fractured loess body / Model test / Double medium / Migration diffusion

CRediT authorship contribution statement

Xiaojun Liu: Writing - review & editing, Funding acquisition. Chaofan Pan: Writing - original draft, Data curation. Lin Feng: Writing - original draft, Validation.

Data Availability

All data, models, and code generated or used during the study appear in the submitted article.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgement

The authors deeply appreciate the financial support from the Shaanxi Natural Science Basic Research Project (Grant no.2020JM-483), Investigation on the Interfacial Bonding Mechanism of Microbial Mineralization Repair Grout for Cracks in Rammed Earth Heritage (Grant no.2025JC-YBMS-551), and the National Natural Science Foundation of China (NSFC) (Grant no.51408464). This paper is also funded by the China Schol-arship Council.

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