Study on the Applicability of Coating Method to Prevent Crystallization of Tunnel Central Drainage Ditch

In recent years, the crystallization of drainage system has appeared in many highway tunnels around the world, which not only affects the drainage function of tunnels, but also threatens the operation safety of tunnels. In view of this problem, a lot of research has been carried out on its formation mechanism and main influencing factors by scholars. However, due to the concealment of the drainage system, effective prevention and control measures have not yet been formed. From the perspective of preventing crystallization, indoor experiments were carried out to simulate the crystallization rules of four coatings and one scale inhibitor under five working conditions. The results show that: The amount of crystallization on the surface of the blank control group is the most, and the rate of crystal formation is faster. Different types of coatings have a certain effect on preventing crystallization. The scale inhibition effect of the coatings is as follows: superhydrophobic coating > fluorocarbon coating > waterborne epoxy coating > oily epoxy coating. The superhydrophobic coating has the highest scale inhibition efficiency, up to 31.9%. The scale inhibitor has a significant effect on preventing crystallization in the early stage, but with the increase of the test cycle, the scale inhibition efficiency gradually decreases.