[PDF] - -Atheb. GEOHAZARD ASSESSMENT PROGRAM NORTH CENTRAL REGION - ATHABASCA PDF Document

SLIDE 1

GEOHAZARD ASSESSMENT PROGRAM NORTH CENTRAL REGION - ATHABASCA 2014 INSPECTION

Atheb.
Transportation

THURBER ENGINEERING LTD.

Site Number Location Name Hwy km

NC 17a

North of Fort McMurray

Hwy 63 Twinning Borrow

63:12 2.2 to 2.9

Pits A and B Legal Description UTM Co-ordinates (NAD 83)

NW7 and SW18-90-09-W4M

12 N 6295275

E 473365

Date PF CF Total Previous Inspection

June 11 ,2013 14 3 42

Current Inspection:

May 21 ,2014 15 3 45

Road AADT:

21360

Year:

2013

Inspected By:

Tarek Abdelaziz and Don Proudfoot (Thurber) Roger Skirrow, Arthur Kavulok, Gerry LeMay (TRANS)

Report Attachments:

P' Photographs P' Plans

r Maintenance ~ems

Primary Site Issue: Dimensions: Date of any remediation: Maintenance: Observations:

p Pavement Distress P' Slope Movement

Client: File: e-file: Alberta Transportation 15-16-314 \\H\15\16-314 NC17a

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 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

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. 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 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 ).

Description Worse?

Uneven pavement surface in SBL at km 2.4; new 40 m

r

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'

f 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

Date: July 30, 2014 Page: 1 of 3

SLIDE 2

r Erosion

P ' Seepage P' Bridge/Culvert Distress

r Other

I n s t r u m e n t a t i

n

: (1 SJ) K m 2 . 4 : W a t e r p e n d i n g a l

n

g t h e w e s t d i t c h

u

t s i d e t h e h e a v e d a r e a s a n d

n

t h e s h

u

l d e r

f

t h e h i g h w a y ; s a g p

n

d s a n d s t a n d i n g w a t e r a l l

v

e r t h e s l

p

e ( e x t r e m e l y w e t c

n

d i t i

n

) ; f a s t s e e p a g e f r

m

t h e e x p

s

e d f a c e

f

t h e l

w

e r s l u m p h e a d s c a r p c r a c k K m 2 . 7 : S a g p

n

d w i t h i n t h e l

w

e r l a n d s l i d e ; w a t e r p e n d i n g i n t

d

i t c h ; s l

p

e s a r e v e r y w e t a n d w a t e r f l

w

i n g

u

t

f

t h e s

u

t h s l u m p a r e a K m 2 . 4 : I n s t r u m e n t s a r e e i t h e r s h e a r e d

f

f

r

d a m a g e d a n d u n r e p a i r a b l e .

r

K m 2 . 7 : S l 9 9

2

d i s p l a y e d a r a t e

f

m

v

e m e n t

v

e r 2 . 6 t

2

2 . 4 m d e p t h to a c u r r e n t r a t e

f

1 . 7 m m / y r . A l l

t

h e r s l

p

e i n c l i n

m

e t e r s h a v e s h e a r e d

f

f d u e t

t

h e l a n d s l i d e m

v

e m e n t s . A s s e s s m e n t ( R e f e r t

a

t t a c h e d F i g u r e ) : T h e e x i s t i n g l a n d s l i d e s and s l u m p s a r e a r e s u l t

f

p r

g

r e s s i v e f a i l u r e in t h e w e a k c

l

l u v i u m in r e s p

n

s e t

h

i g h w a y c

n

s t r u c t i

n

c u t s . K m 2 . 4 : T h e l a n d s l i d e c

n

t i n u e s t

c

a u s e b u l g i n g in t h e w e s t d i t c h a n d h i g h w a y S B L s u r f a c e . T h e l a n d s l i d e h a s b e e n a c t i v e a s r e v e a l e d f r

m

t h e r e t r

g

r e s s i

n
f

b a c k s l

p

e h e a d s c a r p , n

t

i c e a b l e h e a v e in the west ditch and the highway surface, development of new cracks on the highway surface, r e t r

g

r e s s i

n

a n d m

r

e d r

p

a l

n

g t h e h e a d s c a r p c r a c k s

f

t h e u p p e r a n d l

w

e r s l u m p s . M i l l i n g t h e h i g h w a y in 2 1 3 b y 4 t

1

5 m m w a s b e n e f i c i a l t

p

r

v

i d e a s m

t

h r i d e t

m
t
r

i s t s d r i v i n g a l

n

g t h e h i g h w a y s u r f a c e . It s h

u

l d b e n

t

e d h

w

e v e r t h a t i t i s p r e f e r r e d t

c
n

s i d e r p a t c h i n g t h e h i g h w a y s u r f a c e i n t h e f u t u r e r a t h e r t h a n m i l l i n g t h e p a v e m e n t s i n c e t h e l a n d s l i d e i s t

e

i n g

u

t a t t h e h i g h w a y s u r f a c e a n d r e m

v

i n g t h e t

e

b y m i l l i n g t h e p a v e m e n t r e d u c e s t h e t

e

l

a

d a n d a c c e l e r a t e d l a n d s l i d e m

v

e m e n t . K m 2 . 7 : T h e u p p e r b a c k s l

p

e s l u m p s a n d l

w

e r l a n d s l i d e h a v e b e e n v e r y a c t i v e a s r e v e a l e d f r

m

t h e s i g n i f i c a n t r e t r

g

r e s s i

n
f

e x i s t i n g h e a d s c a r p s a n d t h e d e v e l

p

m e n t

f

d i s t i n c t t

e

r

l

l s . T h e l

w

e r l a n d s l i d e h a s m

v

e d s i g n i f i c a n t l y s i n c e 2 1 3 a n d i s c u r r e n t l y b l

c

k i n g t h e w e s t d i t c h a n d l a n d s l i d e d e b r i s h a s e n c r

a

c h e d i n t

t

h e h i g h w a y s h

u

l d e r w i t h i n t h e h i g h w a y c l e a r z

n

e c r e a t i n g s a f e t y h a z a r d t

m
t
r

i s t s . R e c

m

m e n d a t i

n

s : A t km 2 . 4 , t h e d i t c h b

t

t

m

s h

u

l d be r e

t
u

c h e d u s i n g a g r a d a l l e x c a v a t

r

to i m p r

v

e d i t c h d r a i n a g e . E x c a v a t e d d i r t f r

m

t h e d i t c h s h

u

l d be p u s h e d b a c k a g a i n s t t h e t

e
f

t h e s l

p

e . M i n

r

c

n

t

u

r i n g ( w i t h

u

t s i g n i f i c a n t l y c h a n g i n g g r a d e s )

f

t h e s h a l l

w

s l u m p s u s i n g a w i d e p a d d

z

e r w

u

l d a l s

b

e b e n e f i c i a l t

s

e a l u p c r a c k s . C

n

s i d e r a t i

n

s h

u

l d a l s

be

g i v e n f

r

s e a l i n g n e w

p

e n c r a c k s

n

t h e h i g h w a y s u r f a c e a n d p l a c i n g a n A C P

v

e r l a y

n

t h e h i g h w a y w h e n r e q u i r e d t

m

a i n t a i n a s u i t a b l e s m

t

h s u r f a c e . A t k m 2 . 7 , t h e t

e
f

t h e l

w

e r l a n d s l i d e s h

u

l d be s h a v e d to g e t p

n

d e d w a t e r f l

w

i n g i n t

t

h e d i t c h a g a i n a n d c l e a r t h e s h

u

l d e r

f

l a n d s l i d e d e b r i s , w h i l e m i n i m i z i n g t h e a m

u

n t

f

s u p p

r

t t h a t i s r e m

v

e d f r

m

t h e t

e
f

t h e s l i d e . M i n

r

c

n

t

u

r i n g ( w i t h

u

t s i g n i f i c a n t l y c h a n g i n g g r a d e s )

f

t h e l

w

e r l a n d s l i d e u s i n g a w i d e p a d d

z

e r w

u

l d a l s

be

b e n e f i c i a l t

s

e a l u p c r a c k s a n d r e m

v

e l

w

s p

t

s w h e r e s u r f a c e w a t e r c a n a c c u m u l a t e a n d s e e p i n t

t

h e l a n d s l i d e . T h e l

w

e r l a n d s l i d e s h

u

l d b e v i s u a l l y m

n

i t

r

e d by t h e l

c

a l M C I a n d l a n d s l i d e d e b r i s s h

u

l d be c l e a r e d p e r i

d

i c a l l y ( a s r e q u i r e d ) t

r

e d u c e t h e r i s k

f

d i r t f r

m

e n c r

a

c h i n g i n t

t

h e h i g h w a y l a n e s . An a l t e r n a t i v e s h

r

t t e r m m e a s u r e w

u

l d be t

i

n s t a l l a c

n

c r e t e j e r s e y b a r r i e r d e b r i s b a r r i e r in t h e h i g h w a y d i t c h t

r

e t a i n t h e l a n d s l i d e d e b r i s . In t h i s c a s e a g u a r d r a i l w

u

l d a l s

n

e e d t

b

e i n s t a l l e d t

p

r

t

e c t t r a f f i c f r

m

a p

t

e n t ial c

l

l i s i

n

w i t h t h e b a r r i e r .

Client: File: e-file: Alberta Transportation 1 5

1

6

3

1 4 \ \ H \ 1 5 \ 1 6

3

1 4 N C 1 7 a D a t e : J u l y 3 , 2 1 4 Page: 2 of 3

SLIDE 3

It is understood that the existing highway will not be re-located and that Parsons interchange will tie in into existing highway alignment to the north of the site, and therefore it will be required to design and implement a long-term remedial measure to reduce the risk of impacting the highway conditions in response to continued backslope landslide movements. Pile walls, with the piles being socketed into the competent limestone, and above-ground retaining walls could be considered to retain the toes of the landslides.

Client: File: e-file: Alberta Transportation 15-16-314 \\H\15\16-314 NC17a Date: July 30, 2014 Page: 3 of3