A case study on safe sheet pile driving with vibration monitoring

For the rehabilitation and stability improvement of a dike sheet piles were vibratory driven into the crest of the embankment. However, at the toe of the dike at a depth of 0.8 m a gas pipe had been installed supplying the harbour of Antwerp with liquid hydrogen under a pressure of 100 bar. The horizontal distance to the sheet pile wall over a length of 800 m was approximately 6 m. The vibration levels that could occur at the pipe during driving had to be assessed and despite little knowledge on the level of vibrations that could result in damage to the gas line, the permissible limit values had to be established. Finally during driving of the sheet piles the vibrations and settlements were continuously measured at critical locations. The driving activities were completed without any damage. This paper comments on soil conditions and preliminary vibration measurements in the absence of the gas pipe as well as definition of acceptable vibration levels and finally the monitoring results.