Keyhole Studies and Reports
Why Cities Are the Frontline Defense Against Climate Change, 2019
Cities and other urban areas consume more than two-thirds of global energy and emit more than 80 percent of the world’s total greenhouse gases, and many, because of their location, are expected to suffer the most significant consequences of climate change.
This paper identifies how cities can use keyhole coring and reinstatement technology to reduce both GHC emissions and costs. By performing utility cuts using keyhole technology, GHC emissions can be reduced from 845lbs for a conventional excavation and repair to 69lbs per cut as well as reducing costs by up to 87%.
Proceedings of the International Gas Research Conference, 2014
A Cost Savings Strategy for Minimizing Pavement Restoration Costs
The cost of installing and maintaining underground utilities continues to increase. Pavement restoration costs can be reduced by as much as 80% by employing new and safer construction techniques such as the keyhole coring and reinstatement process developed and field proven over
20 years in the gas industry.
This paper identifies a core strategy for addressing the short-term issues of pavement failure related to utility excavations using solutions with long-term benefits. In doing so, it focuses on the need for highway agencies and municipal public work officials to provide and maintain a
smooth and safe road surface, while addressing assessment, inspection, and maintenance of utility infrastructures buried under the roads. As time goes on, more of the underground utility infrastructure reaches the end of its useful life, and more utility excavations will be required to
maintain and replace this aging infrastructure.
ROAD UTILITY CUTS - National Research Council of Canada and U.S. Army Corps of Engineers
The research and development project entitled "Restoration of Utility Cuts (RUC)" is a joint effort involving a number of North American organizations including cities, utility companies and U.S. State departments of transportation. The objective of the project was to develop a guide for best restoration practice based on sound engineering principles. The National Research Council Canada and the U. S. Army Corps of Engineers have joined forces and built a collaborative research project, which investigated the problem and developed the necessary corrective measures for restoration practices that lead to poor performance in the past. The project was managed by a steering committee formed from member organizations contributing to the consortium.
The Toronto field experiment was one of five RUC project sites selected to cover a wide range of utility cut restoration practices and environmental conditions. The Toronto experiment offered an opportunity to investigate the use of unshrinkable fill, a concrete low strength material (CLSM), as a backfill for reinstating utility cuts. City of Toronto specifications for unshrinkable fill follow general flowable fill material guidelines and have been used effectively since 1988. The city manages the quality of this material through a certification system that produces a list of approved unshrinkable fill suppliers (current list includes approximately 20 manufacturing plants). The experimental site included two cut sections, a conventional transverse trench and a keyhole. This report discusses the outcome of in-situ tests conducted in Toronto and laboratory investigations performed at the NRC campus in Ottawa.
The Golder Report - Longitudinal testing and report on the keyhole coring process
This study is an update of the work carried out over the previous ten years on the materials and installation methods used to repair or install subsurface utility plant using Keyhole Technology. Keyhole Technology was originally developed by The Consumers Gas Ltd. (now Enbridge Gas Distribution) over the ten years. The method developed is less intrusive employing, among other things, a rotary cutter and improved pavement reinstatement techniquires including a propietary pavement cutting drill to remove the pavement surface. Using the cutter, the pavement coupon is removed and preserved. The hole is vacuum excavated to expose the plant and the repair iof the plant or installation of new equipment is achieved using long handled tools. After the reapir, the hole is backfilled and the pavement coupon is reinstated with a proprietary bonding compound (Utilibond) bonding the coupon back into place as a permanent repair.
The Golder study is the only longitudinal engineering study of its kind that examines the core reinstatement process over a ten year period
North American Society for Trenchless Technology (NASTT) NO-DIG, New Orleans, Louisiana
Healing the Utility Cut: A Unique Coring and Pavement Restoration Process
E. Marshall Pollock, President & CEO, Utilicor Technologies Inc., Toronto, ON, Canada ABSTRACT: This paper discusses Utilicoring™, a unique pavement excavation and restoration technology. This technology was developed and field-proven over the last ten years by Enbridge Consumers Gas. This process facilitates utility access to underground plant and is a key cost-saving element in the growing utility maintenance trend to “keyhole” technology, which allows crews to cost-effectively perform repair or maintenance work on underground pipe or other buried plant from the road surface without resort to more costly, disruptive and inherently more dangerous excavation methods. It also has direct application to other utility service and trenchless operations including test holes and daylighting for directional drilling, inspection holes for pipeline integrity and subsurface utility engineering.