Preliminary Design and Engineering of Pipe Ramming Installations

Abstract

Installation of new buried pipes and culverts, and replacement of existing ones utilizing trenchless technologies, is increasing in popularity because these methods mitigate many of the surface disturbances associated with conventional open-cut placement. Pipe ramming is an efficient technique that allows installation of casings in soils that can present difficulties for other trenchless technologies. Despite increasing usage, little technical guidance is available to owners and engineers who plan installations with pipe ramming. This paper provides an overview of the pipe ramming technique, possible design procedures, and governing mechanics associated with pipe ramming, with the goal of providing a baseline for engineered installations and identifying areas for further research. Methods to estimate soil resistance to ramming, analysis of ground deformations, and ground vibrations are discussed and compared with measurements observed in field installations. Soil resistance predictions based on conventional jacking methods are shown to underpredict measured resistances inferred from dynamic load testing. Empirical Gaussian settlement models commonly employed in tunnel engineering were shown to result in somewhat inaccurate predictions for an observed pipe ramming installation in cohesionless soils. Field measurements of the ground vibrations resulting from ramming are presented and compared with commonly used safe vibration standards developed for residential structures; the frequencies of vibration generally range from 20–100 Hz, are considerably high for small source-to-site distances, and attenuate rapidly with radial distance. In general, the study lays a basis for planning pipe installation projects with the intent of providing technical advancement in pipe ramming.