Vibration Analysis of a Soil Freezing Plant

The execution of tunnel projects leads to particular problems on soil with low strength. By freezing the soil, the strength of soils at critical areas of construction sites increases. This helps reducing the complex safeguards that are required when setting tubbings. In this case, the reliability of the soil freezing machine is an essential key point for securing an undisturbed safe progress of the construction works. Therefore, the machines are preferably run redundant.

During the building of an underground chute that was situated close to the Elbe River, the compressor unit of the refrigerating system suffered from several defects, indicating vibration problems. The subsequent vibration measurements at the construction site showed resonant vibrations during the operations. Constructional modifications were undesirable due to extensive time- and financial investments. As a result, a barred speed range was introduced to the plant operation. The corrective action proved to be successful when the machines were running free of failure from that point.