Influence Of Electromagnetic Field On Crystallization Of Tunnel Drainage Pipes

Abstract

The salts contained in hard groundwater often lead to crystallization and blockage of tunnel drainage pipes. In this paper, based on the principle of scale removal and inhibition, indoor tests were implemented so as to study the influence law of water filling conditions and different combinations of electromagnetic compound field and the crystallization of tunnel drainage pipes. The results showed that: (1) Under the action of applied electric field, electromagnetic compound field had a certain inhibitory effect on calcium carbonate crystallization process, resulting in changes in crystal structure morphology According to the test, the electromagnetic compound field had significantly greater influence than that of individual electric field or magnetic field under the same test parameters. After electromagnetic compound field treatment, the crystals became loose, unstable and irregular. (2) Different parameter combinations of electromagnetic compound field had different effects on crystallization. Among the parameter combinations, 0.1 T-5 V and 0.2 T-9 V were better parameter combinations, where the effect of 0.2 T is better than that of 0.1 T. (3) The influence of electromagnetic compound field on crystallization was more and more significant with time. After a certain time, new crystals were formed while old crystals were flaked off, the so-called process of “new crystalline matters replacing old ones”. Different combinations of parameters had different effects on crystallization, and the average anti-crystallization efficiency for the best combination of parameters was 46.43%. (4) Crystallization was more likely to occur in the drainage pipe under the “half-filled” condition than that under the “fully filled” condition. This was because the electromagnetic compound field promoted crystallization in the early stage, and gradually inhibited crystallization over time. Regardless of the water filling conditions of the drainage pipe, the electromagnetic compound field has more salient effects on crystallization over time. The study results can provide technical support for preventing crystal blockage of tunnel drainage pipes.

Keywords

• tunnel engineering
• drainage system
• crystal blockage
• model test
• electromagnetic compound field