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.