NWT RESEARCH DATABASE

Tags: physical sciences, geotechnical survey, transportation, aggregate resources

Objective(s): To confirm the volume, quality and extent of material at Borrow Sources 174 and 309; and, to prove the volume, quality and extent of material at Borrow Sources 312 West and PW19A available for use as supplemental borrow material during construction of the Inuvik to Tuktoyaktuk Highway.

Project Description: The Government of the Northwest Territories – Department of Transportation (DOT) proposed to conduct geotechnical investigations in the winter of 2014. The 2014 Program will be conducted to: • confirm the volume, quality and extent of material at Borrow Sources 174 and 309; and • prove the volume, quality and extent of material at Borrow Sources 312 West and PW19A available for use as supplemental borrow material during construction of the Inuvik to Tuktoyaktuk Highway. The Program will consist of: • drilling up to 62 boreholes at Borrow Source 174; • drilling up to 45 boreholes at Borrow Source 309; • drilling up to 27 boreholes at Borrow Source 312 West; • drilling up to 15 boreholes at Borrow Source PW19A; • obtaining representative samples from each borehole drilled for further analysis; • constructing approximately 70 km of winter access trail; • constructing pads for two winter camp locations; • mobilizing, setting up and operating a single 34-person, mobile sleigh camp at each of two camp locations; • mobilizing all equipment, fuel and personnel with the sleigh camp during the Program; and, • storing the sleigh camp and fuel at Borrow Source 174 A winter access trail route will be scouted and marked between the constructed ITH alignment (near Borrow Source 177) and Borrow Source 309 between March 15 and March 17 by an experienced Inuvialuit scout, a Wildlife Monitor and the trail construction supervisor. Access trail construction will begin March 16 and be completed by March 19. The access trail will be constructed of 20 cm packed snow on land, and lakes will be used as much as possible to minimize overland crossings. The Program personnel will mobilize to Tuktoyaktuk March 18, and will participate in a Program orientation March 19. From March 20-21, the sleigh camp, with all equipment, fuel and personnel will mobilize from Tuktoyaktuk to Borrow Source 309 by travelling along the constructed highway alignment and the winter access trail. Geotechnical investigations at Borrow Source 309 will be conducted March 22-27. While drilling occurs at Borrow Source 309, construction will continue on the winter access trail from Borrow Source 309 to 312 West and on to PW19A. On March 28, the drill units will mobilize to Borrow Source 312 West, to conduct geotechnical investigations between March 28 and 29. The drill units will then mobilize to Borrow Source PW19A on March 30 to continue the geotechnical investigation. Work at Borrow Source PW19A will be completed on March 31 or April 1. While drilling activities are occurring at Borrow Source 312 West and PW19A, Program personnel will use the camp at Borrow Source 309. The sleigh camp and the drill units will mobilize to Borrow Source 174 on April 1-3, with the geotechnical investigations being undertaken April 3-9. Mobilization of equipment and personnel back to Tuktoyaktuk will occur April 9-10. The sleigh camp and fuel will be stored at Borrow Source 174 for use during the Year 2 highway construction season. The camp will be stored on timbers and a pad of adequate thickness to protect the permafrost. A total of up to 149 boreholes will be drilled at Borrow Sources 174, 309, 312 West and PW19A during the 2014 Program. The boreholes will be located in a manner to focus the 2014 geotechnical investigation on select areas with the borrow sources. Specific borehole locations will be selected in advance through desktop studies and previous experience proving boreholes. Pioneering and proving boreholes will be drilled at each borrow source. Pioneering holes will be spaced approximately 200-500 m apart in a grid pattern. Proving boreholes will then be drilled around and between the pioneering boreholes, and will be spaced approximately 100-120 m apart. Two track-mounted drill units with 6” augers will be used to drill the boreholes. Boreholes will be drilled at varying depths between 6-15 m until massive ice or ice-rich sediments are encountered. Soil samples will be collected from all boreholes drilled and stored in 20 L pails. Samples will then be transported to Inuvik for index testing, and for shipment to a laboratory in the south for further testing. Boreholes will be backfilled using a mixture of cuttings from drilling and bentonite to seal the hole. A summary of this Program’s findings will be provided to the Aurora Research Institute. The fieldwork for this study will be conducted from March 15, 2014 to April 10, 2014.