Evaluation of advanced drainage treatment for old tunnel drainage system in Korea

• The treatment of clogging in the drain aperture of old tunnels was evaluated by conducting the indoor validation test.
• Quantum Stick showed the reasonable effect of scale removing under the condition of more than velocity limit.
• When the Quantum Stick was set with the angle of more than 5° of the drain aperture’s gradient, its effect was obvious.

This study was dealt with clogging problems of the drain aperture in old tunnels. The precipitates in the drainage were mainly generated by degradation of the tunnel concrete lining. The degradation was made by the chemical reaction between the concrete material and groundwater. If the degree of precipitation is high in the tunnel drainage, the groundwater cannot flow easily in it. Consequently, the groundwater level will go up, and this can lead to the highest water pressure which affects to the structural risk of tunnel. The degraded drainage causes to generate not only the structural stability of tunnel, but also the additional maintenance problem. Up to this time the technical study of preventing the scale for just tunnel drain aperture was rare. However, there are some preventive technologies about the scale for the industrial facilities such as oil pipe lines etc. There are two most popular technologies. One is Quantum Stick using Brown’s principle of quantum mechanics and the other one is Magnetizing device to inhibit the scale formation by changing the form of calcium carbonate particles. In this study, in order to improve the clogging problem in the tunnel drain aperture the elementary technologies were introduced. In addition, the laboratory tests were conducted to evaluate their applicability using the results from SEM and XRD analysis on the sediment generated during the test. As a result, Quantum Stick showed the reasonable effect of scale removing under the condition of more than velocity limit.