Analysis of a 610-mm-Diameter Pipe Installed Using Pipe Ramming

Abstract

Departments of transportation are increasingly embracing pipe ramming for culvert installation under roadways due to its cost effectiveness and ability to mitigate problems associated with open-cut trenching. Despite the increase in use, little technical guidance is available for the engineering of pipe-ramming installations. This study presents the analysis of the performance of an instrumented 610-mm-diameter steel pipe installed using pipe ramming. Measurements include ground surface movement and dynamic force and velocity waveforms to obtain driving stresses, hammer-pipe energy transfer, and static and dynamic soil resistance during the installation. Ground movements are compared to existing settlement prediction models. Inverted normal probability distribution models commonly used in tunnel engineering were evaluated and were observed to capture the observed settlement close to the center of the pipe but did not accurately predict the observed transverse settlement profiles. The transfer of energy was observed to range from as low as 17–39% of the estimated hammer energy. Compressive stresses were observed to remain relatively constant over the penetration length observed and were well below the yield stress of the pipe. Soil resistance derived from wave equation analyses were compared to four pipe-jacking models to evaluate their accuracy and applicability for planning pipe-ramming installations. The jacking models bracketed the static soil resistance components of the wave analysis, indicating that the models may be adopted for pipe-ramming applications pending empirical modification.