In order to improve maintance of drainage pipes within road and railway tunnels the free cross section of the pipes should be monitored. The minerals in the water will precipitate over time and form hard deposits thus reducing the cross section over time. One way of monitoring this is by analyzing the vibration characteristics of pipe sections similar to the methods used in condition monitoring.

Since these scalings gradually develop, the vibration characteristics have to be analyzed continously. This analysis is done using different levels of approximation with the tools of rigid body mechanics. Furthermore a way to measure the changes in the lab using a substitute material is presented and compared to simulations. Finally measurements in a railway tunnel (Siebergtunnel) demonstrate the feasibility of the proposed method.