Horizontal Directionally Drilling a 320m HDPE 600, 700 800mm dia. Triple Barrel Sanitary Siphon under the Red Deer River

摘要

The North Highway Connector (NHC) project consists of an expressway ring road around the East side Red Deer, arntraffic bridge and major underground deep utilities that combine the City of Red Deer and South Red Deer RegionalrnWastewater Commission (SRDRWC) wastewater transmission mains into a triple barrel river crossing siphonrnsystem. This report describes the triple barrel horizontally directionally drilled (HDD) River crossing aspect of thernNHC Contract A4 project.rnAs this was a multi-phased project, site conditions were changing continuously during the design period. The designrnteam needed to be aware of the changing site conditions and as such, needed to be in constant contact with all otherrnteams involved to insure design details represented the current conditions.rnThe Owners were concerned about the risk associated with the HDD River crossing construction and the risk wasrnmitigated by involving all stakeholders for the project (Contractor, Consultant and both Owners - City of Red Deerrnand the SRDRWC) by developing a comprehensive risk analysis whereby all risk occurrences, probabilities andrnresponsibilities were investigated and costs quantified. This was also supplemented by turbidity tests for the RedrnDeer River during construction. Other challenges for the HDD river crossing included a two stage tender process,rncasing installation and the on-site disposal of drilling mud.rnIn conclusion, the detailed efforts by all parties involved during this contract produced a project that came in underrnbudget and met deadline targets along with showcasing unique aspects of risk mitigation processes that can be usedrnas an example for similar projects in the future.