Simplified model for numerical calculation of pull forces in static pipe-bursting operations

Trenchless pipe replacement, or pipe bursting, is defined as the replacement of an original pipe by fragmenting the existing conduit and simultaneously installing product pipe in its place. In the static method of pipe replacement, the original pipe fails in tension by radial forces developed from the cone-shaped bursting head geometry that are applied to the pipe wall from within the pipe, as it is pulled or pushed through the existing pipe. The fragmented pieces are pressed into the surrounding soil as it is being displaced, thus creating a cavity for the product pipe. This paper presents a simplified model to calculate the maximum pull force (a function of the friction, bursting, and soil compression shear forces) required to be overcome to complete a static pipe-bursting pull. Based on site-specific information, the model provides an initial avenue for contractors, engineers, and manufacturers in planning successful trenchless pipe replacement projects.