Response of a polyvinyl chloride water pipe when transverse to an underlying pipe replaced by pipe bursting

An existing deteriorated or hydraulically undersized pipe can be replaced with a new pipe by static pipe bursting. Cavity expansion during pipe bursting induces ground movements, which may potentially damage nearby buried utilities if they are in close proximity to the pipe bursting operation. A large-scale pipe bursting experiment was performed in an 8 m long, 8 m wide, and 3 m deep test pit filled with a well-graded sand and gravel soil. A polyvinyl chloride (PVC) pipe, crossing transversely and 0.45 m above the existing pipe being replaced, was instrumented with strain gages to quantify the response of that transverse utility to the ground movements associated with pipe bursting. In this paper, the measured strain and corresponding deflection of the PVC pipe are examined and compared with measurements of surface uplift. The maximum longitudinal strain measured in the pipe was less than 0.1% and its vertical diameter decreased by only 0.5%, suggesting that ground displacements induced by pipe bursting did not jeopardize the transverse water pipe's long-term performance, provided its joints were not damaged. A simplified design equation is introduced and shown to provide estimates of maximum longitudinal strain in the PVC pipe close to those measured during the laboratory experiment.