Field Measurements of Pipe Ramming-Induced Ground Vibrations

Abstract

Pipe ramming is an emerging trenchless technique that allows installation of pipes and culverts in soils that can pose difficulty to other trenchless technologies. However, because pipe ramming hammers provide high-frequency impact blows to the pipe, high-magnitude stress waves travel down the pipe and are transmitted to the surrounding soil. This can have a serious adverse effect on adjacent structures and nearby utilities if located sufficiently close to the pipe alignment. The potential effects include differential settlements, densification, and local liquefaction depending on the soil and groundwater conditions. Owing to the lack of field observations in the literature, this study was conducted to observe the ground vibrations that can result from pipe ramming and to provide guidelines for the prediction of pipe ramming-induced vibration. An experimental pipe-ramming project was conducted that consisted of the installation of open-ended steel pipe 1,070 mm in diameter and 36.5 m long rammed with two pneumatic hammers. Observations indicated that the vibrations measured at the ground surface largely comprised surface waves, and that vibrations propagate most intensely from the face of the pipe, but also from the surface area of the embedded casing. Ground vibrations are presented as a function of frequency content, magnitude of peak particle velocity, proximity to the source, and direction of propagation. The information obtained from the experimental evaluation of pipe ramming-induced ground vibrations reported herein can provide the means for a first approximation of vibration-induced damage susceptibility.