sustainable slope stabilization using recycled plastic pin · •recycled plastic pin (rpp)...
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Sustainable Slope Stabilization using Recycled Plastic Pin
Sahadat Hossain, Ph.D., P.E.
Sadik Khan, Ph.D., P.E.
Shallow Landslides in Highway Slopes
Shallow Landslides in Clay Soil
Expansive Clay in US
Legend:
Red: Clay having high swelling potential
Blue: Less than 50% of clay contents having high
swelling potential
Orange: Clay content having slight to moderate swelling
potential
Green: Less than 50% of clay contents having slight to
moderate swelling potential
Brown: Little or no swelling clay
Yellow: Insufficient data
Problems of Expansive Clay
Displacement
ShearStress
Peak O-C
Fully SoftenedPeak N-C
Residual
0.6
0.7
0.8
0.9
1
1.1
1.2
0 1 2 3 4 5
Vo
id R
atio
, e
Number of wet-dry cycle
Change in Void Ratio
Initial Condition
Final Condition
0
20
40
60
80
100
0 2 4
% C
han
ge in
Co
hes
ion
No of Wet Dry Cycle
Changes in Cohesion
0
10
20
30
40
50
0 2 4
% C
han
ge in
Fri
ctio
n A
ngl
e
No of Wet Dry Cycle
Changes in Friction Angle
Fact About Plastic Waste
• 50 Billion Water Bottle end up in US Landfill Each Year
• It may take 700 years to decompose plastic bottles
• Ecosystems and wildlife are negatively impacted by plastic
debris.
What is Recycled Plastic Pin?
• Recycled Plastic Pin (RPP)
• Mainly Polymeric Materials
• Fabricated from Recycled Plastics
• Commercially Available
• RPP Reduces Waste Volume
• Resistant to Biological Exposure
Structural Properties of RPP
Specimen
Batch
No of
Specimens
Tested
Nom. Def.
Rate
(mm/min)
Flexural
Strength
(MPa)
Secant
Flexural
Modulus
E1%
(MPa)
Secant
Flexural
Modulus
E5%
(MPa)
A1 13 - 11 779 662
A4 3 4.27 18 1,388 -
A5 3 5.74 11 711 504
A6 4 3.62 10 634 443
B7 1 4.05 9 544 425
0
1
2
3
4
5
0 1 2 3 4 5
σ(
ksi
)
ε ( inch/inch )
3 point bending test results of RPP
0.5 kips/min 2.7 kips/min 4.9 kips/min
Ref:
Bowders et al., 2003; Hossain et al., 2017
Stabilization of Slopes using RPP
Factor of Safety:
Without Reinforcement
FS = Mr/Md
Factor of Safety:
With Reinforcement
FS = (Mr+∆Mr)/Md
Test Site
Test Site is located over highway US 287, near St. Paul overpass close to Dallas, Texas
Resistivity Profile: RI-1
Resistivity Profile: RI-2
0
10
20
30
40
50
60
70
80
20 40 60 80
Pla
stic
ity
In
dex
Liquid Limit
Plasticity Chart
BH-1
BH-2
BH-3
Site Investigation
Displacement
ShearStress
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
AngleCohesion
Unit
Weight
Elastic
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
Back Analysis of Unreinforced Slope: FS = 1.05
Soil 4
Soil 3
Soil 2 Soil 1 Back Calculated Soil Parameters
Design of Slope Stabilization
RPP Layout
• Equipment: Klemm 802 Drill Rig
• Hammer Type: KD 1101
Installation
Installation
• Rain Gauge
• Instrumented RPP
• Surveying
• Inclinometer
• Moisture Sensor
• Water Potential Probe
Instrumentation
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
Settlement at Crest
Site Photo
17
R. Section 1
Control Section
Control Section 2
R. Section 3
Settlement: 15 in
Settlement: 9 in
-1
0
1
2
3
4
0
1
2
3
4
5
7/16/
11
9/16/
11
11/16/
11
1/16/
12
3/16/
12
5/16/
12
7/16/
12
9/16/
12
11/16/
12
1/16/
13
3/16/
13
5/16/
13
7/16/
13
Dis
pla
cem
en
t (i
nch
)
Rain
fall
(in
ch
)
Date
Comparison of Horzontal Movement at US 287 Slope
Rainfall 2.5 ft-Inc1 2.5 ft-Inc 3
Horizontal Movement
0
20
40
Mo
istu
re
Co
nte
nt
(%)
-20000
-16000
-12000
-8000
-4000
0
Mat
ric
Suct
ion
(p
sf)
-0.5
0
0.5
1
1.5
2
Jul-
11
Aug-1
1
Sep
-11
Oct
-11
No
v-1
1
Dec
-11
Jan
-12
Feb
-12
Mar
-12
Ap
r-12
May
-12
Jun
-12
Jul-
12
Aug-1
2
Sep
-12
Oct
-12
No
v-1
2
Dec
-12
Jan
-13
Feb
-13
Mar
-13
Ap
r-13
May
-13
Jun
-13
Jul-
13
Aug-1
3
Ho
rizo
nta
l D
isp
lacem
en
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
0
4
8
Rain
fall
(i
nch
)
Rainfall Average Rainfall Total Rainfall
Comparison of Rainfall, Moisture Content, Matric Suction and Hor. Displacement
Comparison with Temperature
-0.5
0
0.5
1
1.5
2
40
60
80
100
120
140
1/1/12
2/1/12
3/1/12
4/1/12
5/1/12
6/1/12
7/1/12
8/1/12
9/1/12
10/1/12
11/1/12
12/1/12
1/1/13
2/1/13
3/1/13
4/1/13
5/1/13
6/1/13
7/1/13
8/1/13 D
isp
lacem
en
t (i
nch
)
Dail
y H
igh
est
Tem
pera
ture
(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)
News Clip!!
Comparison of Performance
Northbound and Southbound (Reinforced) Slope
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
Google Earth Image Comparison
Northbound (Control) and Southbound (RPP Stabilized) Slope
Imagery Date: 1/29/2016Imagery Date: 7/14/2015
Imagery Date: 4/10/2013Imagery Date: 6/12/2011
RPP Reinforce Area RPP Reinforce Area
RPP Reinforce Area RPP Reinforce Area
Comparison of Performance
Northbound and Southbound (Reinforced) Slope
Comparison of Performance
Northbound and Southbound (Reinforced) Slope
Traditional Repair
Northbound and Southbound (Reinforced) Slope
01
23456
Pre
cip
itati
on
(in
ch
)
Date
Failure of Northbound Control Slope After Repair
Northbound (Control) and Southbound (RPP Stabilized) Slope on 1/29/2016
Imagery Date: 7/14/2015
RPP Reinforce Area (No Sign of
Failure)
Deep Seated Failure after repair
Recently Published Book
Site Investigation
• Conventional Investigation Methods:
- Provides Information at Certain Points
- Not a General View of Site
- Expensive
Electrical Resistivity Imaging
•An electric current is injected into the ground
through two electrodes
•The resulting potential is measured between two
other electrodes
•Injected current and resulting voltage (potential)
is measured and “apparent resistivity” is calculated
Potential Advantages of ERI
Potential benefits of RI:• Continuous image of the subsurface
• Reduces of risk and liabilities
• Cost-effective design solutions
• Both for forensic and geo-hazard investigation
BH-1 BH-2
BH-2BH-1
Case Studies on the Application of Resistivity Imaging
• Several Case Studies highlighting the applications of RI in MSE wall, slope failure investigation,
pavements, tunnels, Unknown Foundations, Landfills, Ground Water flow and Cave Detection
Line 1
Line 2
Line 3
Slope Failure Investigation Investigation of Seepage
Book in Press
Site Investigation using Resistivity Imaging
Sahadat HossainGolam KibriaSadik Khan
Bore Hole 1 Bore Hole 2
Perched Water Zone 1 Perched Water Zone 2 Resistivity Imaging in MSE Wall Dr. Sadik Khan, P.E.
Assistant Professor
Phone: 601-979-6373
Dr. Sahadat Hossain, P.E.
Professor
Phone: 817-272-3577
Dr. Golam Kibria, P.E.
Phone: 682-203-7611
Tentative Publication Date: September, 2018
Publisher:
CRC Press, www.crcpress.com
The book will be available in Amazon.com both in printed and
kindle version
Thank You