-Atheb. GEOHAZARD ASSESSMENT PROGRAM NORTH CENTRAL REGION - ATHABASCA - PDF document

-Atheb. GEOHAZARD ASSESSMENT PROGRAM NORTH CENTRAL REGION - ATHABASCA • • Transportation 2014 INSPECTION THURBER ENGINEERING LTD. Site Number Location Name Hwy km Hwy 63 Twinning Borrow NC 17a 63: 12 2.2 to 2.9 North of Fort McMurray Pits A and B UTM Co-ordinates (NAD 83) Legal Description NW7 and SW18-90-09-W4M 12 N 6295275 E 473365 Date PF CF Total Previous Inspection June 11 ,2013 14 3 42 May 21 ,2014 15 3 45 Current Inspection: 21360 2013 Road AADT: Year: Tarek Abdelaziz and Don Proudfoot (Thurber) Inspected By: Roger Skirrow, Arthur Kavulok, Gerry LeMay (TRANS) r Maintenance ~ems P' Photographs P' Plans Report Attachments: Active landslides are present in the back slope west of the SBL at Borrow Pits A (km 2. 7) and B (km 2.4). The toe of the landslide at Primary Site Issue: Borrow Pit B is distorting the pavement surface along the south bound lanes. At Borrow Pit A the highway back slope slide is about 100 m in width and extends into the offloaded area behind the crest of the back slope. There are also two slumps in the back slope of the upper offloaded Dimensions: area. The south slump is about 60 m wide and the North Slump is about 40 m wide. At Borrow Pit B the slump in the highway back slope is about 100 m wide, and extends to the top of the highway backslope. Date of any remediation: N/A Km 2.4: Pavement patching to smooth out the highway combined with some minor re-grading to remove humps in the highway west ditch (2007); in fall 2009, ditch was cleaned up , dirt pushed back into the west side of the ditch, and ACP overlay was placed on the highway surface; in fall 2011 , ditch was cleaned up, dirt pushed back into the west side of the ditch, lower slump mass re-graded; Wavy highway Maintenance: surface was milled by 40 to 150 mm in 2013. Km 2.7: Minor re-grading of lower backslope landslide mass to seal up cracks and smooth out dips, slight contouring of the toe by pushing dirt back towards the west side to enhance drainage in the ditch (2011 ). Observations: Description Worse? Uneven pavement surface in SBL at km 2.4; new 40 m r p Pavement Distress wide transverse cracks on highway surface. Km 2.4: After milling the highway in 2013, SBL is currently bulging by about 150 to 200 mm; the head scarp of the backslope landslide above the offloaded area has been active and retrogressed back since the 2013 site inspection visit; further retrogression and drop P' P' Slope Movement of the upper and lower slumps; lower slump is currently not blocking the ditch Km 2.7: Significant movement of the lower landslide and the upper slumps; lower landslide blocked the ditch and debris encroached into the highway shoulder Client: Alberta Transportation Date: July 30 , 2014 File: 15-16-314 e-file: \\H\15\16-314 NC17a Page: 1 of 3