Abstract:

A novel cleaner specifically designed to mitigate crystallizationinduced clogging in tunnel drainage systems is introduced. Analysis of the tunnel crystal samples reveals low concentrations of Ca2+, Mg2+, CO32-, and SO42-and a notably high average concentration of HCO3-. This high HCO3- concentration signifies a predominantly weak alkaline environment, which was identified as the primary cause of crystallization. Utilizing energy spectrum analysis and scanning electron microscopy, the composition and microstructure of the tunnel crystal are characterized, establishing calcitetype calcium carbonate as its primary component. To assess the effectiveness of the cleaner, a simulated experimental device was employed to explore the impact of the water samplecleaner mass ratio on the cleaning rate. To optimize the formulation of the cleaner, the response surface method is employed by combining the main and auxiliary agents. In addition, safety tests for corrosion and solubility were conducted. The results unveil the following key findings: (1) The most effective mixing proportions comprise 7.5%~8.5% sulfonic acid, 0.2%~0.8% DTPMPA, and 0.2%~0.8% PBTCA. (2) The indoor simulations exhibit a cleaning rate fluctuating between 85% and 99.8%. Adjusting the proportions of materials according to different environmental conditions is essential for achieving an optimal cleaning effect.

Key words: tunnel, drainage system, crystallization clogging, chemical cleaner