4a-3 stabilization slope failure_hossain_khan.pdf

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Dr. Sahadat Hossain, P.E.

Dr. Mohammad Sadik Khan, P.E.

Stabilization of Shallow Slope failure on Expansive Clay using Recycled Plastic Pin

• Recycled Plastic Pin (RPP)

• Mainly Polymeric Materials

• Fabricated from Recycled Plastics

• Advantages

• Commercially Available

• Use of RPP Reduces Waste Volume

• Resistant to Biological Exposure

• Typical Composition

• HDPE : 55-90%

• LDPE : 5-10%

• PP, PET, PS : 1% - 10%

• Misc. : 0 – 5%

A 10’ long RPP can replace 500 Soda Bottles

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Factor of Safety:Without ReinforcementFS = Mr/Md

Factor of Safety:With ReinforcementFS = (Mr+∆Mr)/Md

Legend:Red: Clay having high swelling potentialBlue: Less than 50% of clay contents having high swelling potentialOrange: Clay content having slight to moderate swelling potentialGreen: Less than 50% of clay contents having slight to moderate swelling potentialBrown: Little or no swelling clayYellow: Insufficient data

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Expansive Clay

Most Slope Failure in Texas takes place due to the Shrink Swell behavior of Expansive Clay and Formation of Perched Water Zone due to Rainfall

Interstate 30

US 287 US 67

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Site Location

0

10

20

30

40

50

60

70

80

20 40 60 80

Pla

stic

ity

Ind

ex

Liquid Limit

Plasticity Chart

BH-1BH-2BH-3

Bore Hole Location

Depth of Sample

Liquid LimitPlasticity

IndexBH-1 5 48 25BH-1 10 60 33BH-1 15 72 48BH-1 20 64 38BH-2 5 49 26BH-2 10 67 38BH-2 15 73 45BH-2 20 61 35BH-2 25 62 37BH-3 5 52 27BH-3 10 61 34BH-3 15 79 51BH-3 20 58 32BH-3 25 62 40

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RI-1

RI-2

Resistivity Profile: RI-1

Resistivity Profile: RI-1

0

1

2

3

4

5

6

7

8

9

10.00 20.00 30.00 40.00

Dep

th o

f S

amp

le (

m)

Moisture Content (%)

Moisture Variation along the borehole

US 287 BH1 US 287 BH2

0

1

2

3

4

5

6

7

8

0 5 10 15 20 25

Dep

th (

m)

Resistivity (Ohm-m)

Variation of Resistivity

BH-1 BH-2 BH-3

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Soil Type

Friction Angle

CohesionUnit

WeightElastic

Modulus

φ c ϒ E

- ◦ psf pcf psf

1 10 100 125 100000

2 23 100 125 150000

3 15 250 130 200000

4 35 3000 140 250000

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March 2011 March 2012

Reinforced Section 1

Reinforced Section 2 Reinforced Section 3

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Reinforced Section 1: FS = 1.43



Soil Type

Friction Angle

CohesionUnit

WeightElastic

Modulus

φ c ϒ E- ◦ psf pcf psf1 10 100 125 1000002 23 100 125 1500003 15 250 130 2000004 35 3000 140 250000

Back Analysis of Unreinforced Slope: FS = 1.05

Soil 4

Soil 3

Soil 2 Soil 1 Back Calculated Soil Parameters

• Equipment: Klemm 802 Drill Rig

• Hammer Type: KD 1101

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Section No. ofRPP

Installation Time(Day)

Start Date

FinishedDate


192 2 March 01, 2011

March 03, 2011


225 2 March 04, 2011

March 05, 2011


238 3 Feb 29, 2012

March 6, 2012

• Rain Gauge

• Instrumented RPP

• Surveying

• Inclinometer

• Moisture Sensor

• Water Potential Probe

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25

-0.025

-0.02

-0.015

-0.01

-0.005

0

0.0050

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

2/28

/11

3/31

/11

4/30

/11

5/31

/11

6/30

/11

7/31

/11

8/31

/11

9/30

/11

10/3

1/11

11/3

0/11

12/3

1/11

1/31

/12

2/29

/12

3/31

/12

4/30

/12

5/31

/12

6/30

/12

7/31

/12

8/31

/12

9/30

/12

10/3

1/12

11/3

0/12

12/3

1/12

1/31

/13

2/28

/13

Str

ain

(in/

in)

Rai

nfal

l (in

)

Date

Comparison of Strain: Reinforced Section 1, Control Section and Reinforced Section 2

Rainfall IM-3 @ 2ft IM-5 @ 2ft IM-8 @ 2ft

0

2

4

6

8

10

12

14

16

18

20

0 50 100 150 200 250

Set

tlem

ent

(in

)

Distance along Roadway (ft)

Total Settlement of at the crest of US 287 slope

5.6.12 5.6.12 6.6.12 7.13.12 8.3.12 9.8.12 10.6.12 11.10.12

12.13.12 1.10.13 2.9.13 3.7.13 4.5.13 5.20.13 7.1.13 8.2.13

26

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27

0

1

2

3

4

5

6

0 50 100 150 200 250

Set

tlem

ent

(in

ch)

Distance along Roadway (ft)

Incremental Settlement of at Crest of the Slope

8.3.12 1.10.13 4.5.13 5.20.13 8.2.13

28

R. Section 1

Control Section

Control Section 2

R. Section 3

Settlement: 15 in

Settlement: 9 in

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29

-1

0

1

2

3

4

0

1

2

3

4

5

7/16

/11

9/16

/11

11/1

6/11

1/16

/12

3/16

/12

5/16

/12

7/16

/12

9/16

/12

11/1

6/12

1/16

/13

3/16

/13

5/16

/13

7/16

/13

Dis

pla

cem

ent

(in

ch)

Rai

nfa

ll (i

nch

)

Date

Horizontal Displacment with time at Inclinometer 1

Rainfall 2.5 ft-Inc1 6.5 ft-Inc 1 10.5 ft-Inc 1 20.5 ft-Inc 1

30

-1

0

1

2

3

4

0

1

2

3

4

5

7/16

/11

9/16

/11

11/1

6/11

1/16

/12

3/16

/12

5/16

/12

7/16

/12

9/16

/12

11/1

6/12

1/16

/13

3/16

/13

5/16

/13

7/16

/13

Dis

pla

cem

ent

(in

ch)

Rai

nfa

ll (i

nch

)

Date

Horizontal Displacment with time at Inclinometer 3

Rainfall 2.5 ft-Inc 3 6.5 ft-Inc 3 10.5 ft-Inc 3 20.5 ft-Inc 3

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31

-1

0

1

2

3

4

0

1

2

3

4

5

7/16

/11

9/16

/11

11/1

6/11

1/16

/12

3/16

/12

5/16

/12

7/16

/12

9/16

/12

11/1

6/12

1/16

/13

3/16

/13

5/16

/13

7/16

/13

Dis

pla

cem

ent

(in

ch)

Rai

nfa

ll (i

nch

)

Date

Comparison of Horzontal Movement at US 287 Slope

Rainfall 2.5 ft-Inc1 2.5 ft-Inc 3

0

4

8

Rai

nfal

l (i

nch)

Rainfall Average Rainfall Total Rainfall

32

0

20

40

Moi

stur

e C

onte

nt (

%)

-20000

-16000

-12000

-8000

-4000

0

Mat

ric

Suct

ion

(p

sf)

-0.5

0

0.5

1

1.5

2

Jul-1

1

Aug

-11

Sep-

11

Oct

-11

Nov

-11

Dec

-11

Jan-

12

Feb-

12

Mar

-12

Apr

-12

May

-12

Jun-

12

Jul-1

2

Aug

-12

Sep-

12

Oct

-12

Nov

-12

Dec

-12

Jan-

13

Feb-

13

Mar

-13

Apr

-13

May

-13

Jun-

13

Jul-1

3

Aug

-13

Hor

izon

tal D

isp

lace

men

t (i

nch

)

Date

2.5 ft-Inc1 6.5 ft-Inc 1 10.5 ft-Inc 1 20.5 ft-Inc 1

Rainfall

M/C

Matric Suction

Displacement

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33

0

20

40

Moi

stur

e C

onte

nt (

%)

-20000

-16000

-12000

-8000

-4000

0

Mat

ric

Suct

ion

(p

sf)

-0.5

0

0.5

1

1.5

2

Jul-1

1

Aug

-11

Sep-

11

Oct

-11

Nov

-11

Dec

-11

Jan-

12

Feb-

12

Mar

-12

Apr

-12

May

-12

Jun-

12

Jul-1

2

Aug

-12

Sep-

12

Oct

-12

Nov

-12

Dec

-12

Jan-

13

Feb-

13

Mar

-13

Apr

-13

May

-13

Jun-

13

Jul-1

3

Aug

-13

Hor

izon

tal D

isp

lace

men

t (

inch

)

Date

2.5 ft-Inc 3 6.5 ft-Inc 3 10.5 ft-Inc 3 20.5 ft-Inc 3

Rainfall

M/C

Matric Suction

Displacement

0

4

8

Rai

nfal

l (i

nch)


34

-0.5

0

0.5

1

1.5

2

40

60

80

100

120

140

1/1/

122/

1/12

3/1/

124/

1/12

5/1/

126/

1/12

7/1/

128/

1/12

9/1/

1210

/1/1

211

/1/1

212

/1/1

21/

1/13

2/1/

133/

1/13

4/1/

135/

1/13

6/1/

137/

1/13

8/1/

13 Dis

pla

cem

ent

(in

ch)

Dai

ly H

igh

est

Tem

per

atu

re (

F)

Date

Comparison of Horizontal Movement with Temperature

Daily Highest Temperature 2.5 ft-Inc1 2.5 ft-Inc 3

Shrinkage Crack (Dry Period)

No Crack (Wet Period)

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Loehr et al., 2007

0

2

4

6

8

10

Rai

nfa

ll (i

nch

)


-0.5

0

0.5

1

1.5

2

Jul-1

1A

ug-1

1Se

p-11

Oct

-11

Nov

-11

Dec

-11

Jan-

12Fe

b-12

Mar

-12

Apr

-12

May

-12

Jun-

12Ju

l-12

Aug

-12

Sep-

12O

ct-1

2N

ov-1

2D

ec-1

2Ja

n-13

Feb-

13M

ar-1

3A

pr-1

3M

ay-1

3Ju

n-13

Jul-1

3A

ug-1

3

Hor

izon

tal D

isp

lace

men

t (i

nch

)

Date

2.5 ft-Inc1 6.5 ft-Inc 1 10.5 ft-Inc 1 20.5 ft-Inc 1

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• RPP provided resistance against shallow slope failure

• A Crawler-Mounted Rig, Equipped with a Mast-Mounted Pseudo Vibratory Hammer, Worked Effectively to Install RPPs

• On Average, a RPP Can be Installed within 4 Minutes, and a Total of 100 to 120 RPPs can be Installed in a Single Day.

• Settlement at Control Section is 15 inch

• Settlement at Reinforced Section 1 is 2.5 inch.

• Closer RPP Spacing at Crest Provided Higher Resistance against Slope Deformation

• Only 15% to 16% of the Total Capacity of RPP is Currently Mobilized

• RPP can save the stabilization cost up to 60% - 80% of conventional technique, and have potential to be a effective sustainable alternative to stabilize shallow slope failure.

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Thank You

4a-3 stabilization slope failure_hossain_khan.pdf

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