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Dr. Sahadat Hossain, P.E.Professor, Civil Engineering, The University of Texas at Arlington

Dr. Sadik Khan, P.E. (JSU)Ashrafuzzaman Khan (UTA)

Asif Ahmed (UTA)

Case Studies: Long Term Performance of Highway Slopes Stabilized with Recycled Plastic Pin

Fact About Plastic Bottles!

• 50 Billion Water Bottle end up in US Landfill Each Year

• It takes 700 year to decompose plastic bottles

• Ecosystems and wildlife are negatively impacted by plastic debris.

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• Recycled Plastic Pin (RPP)

• Mainly Polymeric Materials

• Fabricated from Recycled Plastics

• Commercially Available

• RPP Reduces Waste Volume

• Resistant to Biological Exposure

Recycled Plastic Pin to Stabilize Shallow Slope Failure

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

Expansive Clay in US

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Resistivity Profile: RI-1

Resistivity Profile: RI-2

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

Site Investigation

Displacement

Shea

rSt

ress

Peak O-C

FullySoftened

Peak N-C

Residual

Reinforced Section 1: FS = 1.43

Reinforced Section 2: FS = 1.48

Reinforced Section 3: FS = 1.54

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

Design of Slope Stabilization

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RPP Layout

• Equipment: Klemm 802 Drill Rig

• Hammer Type: KD 1101

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• Rain Gauge

• Instrumented RPP

• Surveying

• Inclinometer

• Moisture Sensor

• Water Potential Probe

Instrumentation

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0.0

4.0

8.0

12.0

16.0

0 50 100 150 200 250

Set

tlem

ent

(in

)

Distance along Roadway (ft)

6.6.12 10.6.12 12.13.12 7.1.13 5.15.14 12.24.14 6.18.15 12.15.2015 6.15.2016

Settlement at the crest of slope: US 287

R - 01 R - 02 R - 03

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-0.5

0

0.5

1

1.5

2

2.5

3

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Dis

pla

cem

ent

(in

ch)

Rai

nfa

ll (i

nch

)

Date

Inclinometer - 1 : Cum Displacement A-A with Time

Rainfall 4.5 (ft) 6.5 (ft) 8.5 (ft) 10.5 (ft) 12.5 (ft)

14.5 (ft) 16.5 (ft) 18.5 (ft) 20.5 (ft) 22.5 (ft)

Movement during the failure of Northbound slope

Movement during the failure of Northbound slope

Expansive Behavior

-0.500.511.52

406080

100120140

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

Desiccation Crack (Dry Period)

No Cracks (Wet Period)

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R. Section 1

Control Section

Control Section 2

R. Section 3

Settlement: 15 in

Settlement: 9 in

Settlement at Control Section

News and Media

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Failure Location 3

Failure Location 4

Failure Location Time

Failure Location-1 October 2013

Failure Location -2 October 2013

Failure Location-3 June 2015

Failure Location-4 June 2015

Failure Location 1 Failure Location 2

Failure Location 3

Comparison of Performance Northbound and Southbound (Reinforced) Slope

North Side

September 2015

October 2015

Soil Nailed Wall

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Southbound slope (RPP stabilized)

Northbound slope

(after construction of soil nail wall)

0123456

Pre

cip

itat

ion

(in

ch)

Date

Failure of Northbound Slope After Repair

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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

• 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.

Summary and Conclusion

Upcoming Book

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Thank You