Experiment and Numerical Simulation of Transparent Soil Migrated by High Pressure Rotary Spray Repairing Medicament in Contaminated Soil

Abstract:

High pressure rotary spray technology has just begun to be applied to the repair of contaminated soil in recent years. The law of migration and diffusion of the injected agent is still unclear, which leads to the lack of reliable basis in engineering practice. At the same time, in order to overcome the shortcomings of conventional test methods, transparent soil materials were used to carry out laboratory tests and numerical simulation of the migration of remediation agents for contaminated soil. Considering the coupling of molecular diffusion, mechanical dispersion and convection, an advection-dispersion model was established to investigate migration characteristics of medicament in soil. The research results show that: the transparent soil test technology can visually show the migration process of the medicament and can be applied to study the migration characteristics of the contaminated soil repair agent. Under different soil pressure conditions, there is an optimal mud cake height. Under the same soil pressure, the higher the mud cake height, the smaller the concentration maximum value at the same position. The selection of the mud cake height is related to the setting of the high pressure rotary spray parameter, and has an important impact on the repair effect and efficiency. The migration of the medicament is mainly vertical migration, and the horizontal migration is not obvious. Therefore, in order to ensure that the medicament migrates to the edge of the mud cake at a higher concentration, the medicament should have a higher and uniform initial concentration in the horizontal direction of the mud cake gap.

Key words:high pressure rotary spary;contaminated soil remediation;advection-dispersion model;soil pressure condition;medicament migration