Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory...
Transcript of Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory...
![Page 1: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/1.jpg)
www.eng.chula.ac.th
Laboratory Investigation of Laboratory Investigation of VetiverVetiver Root Laboratory Investigation of Reinforcement for Slope
VetiverVetiverVetiver Root Root Laboratory Investigation of Laboratory Investigation of VetiverReinforcement for Slope Reinforcement for Slope Reinforcement for Slope Protection
Presented by Presented by Dr.Dr. BoonratBoonrat LohwongwatanaPresented by Presented by Dr.Dr.Dr.Faculty of Engineering,
BoonratBoonrat LohwongwatanaLohwongwatanaDr. BoonratBoonratFaculty of Engineering, Faculty of Engineering, Chulalongkorn
LohwongwatanaLohwongwatanaChulalongkornChulalongkorn University ChulalongkornChulalongkorn
CoChulalongkorn
CoCo-University University University University
CoCo---authors:Suched
CoCoCo authors:authors:authors:Suched LikitlersuangSuchedSuched Likitlersuang
SirintraLikitlersuangLikitlersuangLikitlersuang
SirintraSirintraSirintra VannoLikitlersuangLikitlersuang
VannoVanno and SirintraSoamshine
Sirintra VannoVannoVanno and and SirintraSirintraSoamshineSoamshine BoonyanantaSoamshineSoamshine BoonyanantaBoonyanantaChulalongkorn
BoonyanantaBoonyanantaChulalongkornChulalongkorn University
TTThe he he Sixth International Conference on Sixth International Conference on VetiverVetiver (ICV(ICV-(ICV-(ICV-(ICV 6), 6), 6), DanangDanang, Danang, Danang, Danang Vietnam, 5 Vietnam, 5 –– 8 May 2015
![Page 2: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/2.jpg)
www.eng.chula.ac.th
Mode of failure (Mode of failure (SkepmtonSkepmton, 1953)
Failure AngleSlope after Failure
Total Length (L)
Foot
Toe
Degree of Rotation
Slope before Failure
Max. Depth(D)
Flows Slides Slumps
D/L = 0.5 D/L = 0.5 –– 3% 5 5 –– 10% 15 15 –– 30%
![Page 3: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/3.jpg)
www.eng.chula.ac.th
Diverse vegetation
Grass
Potential deep-seated failurePotential shallow failure
Grass root
Live pole
Soil nail
Live pole
Self-regenerative and sustainable (almost maintenance free)
(root of small tree/shrub)
![Page 4: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/4.jpg)
www.eng.chula.ac.th
Two effects of vegetation on soil slope
[1] Hydrology - Plant roots may increase subsoil permeability at the same time the vegetation will intercept rainfall and transpire water, eventually leading to lower water pressures (i.e., higher suctions) in the slope.
[2] Mechanical - The presence of the roots will lead to reinforcement in the penetrated regions.
![Page 5: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/5.jpg)
www.eng.chula.ac.th
RootRoot-Root-soilsoil-soil-water interactionEvapotranspiration
Soil
Atmosphere
Rainfall
Water uptake
EvaporationInfiltration
Plant
Complex plant-soil-atmospheric interaction(Greenwood et al., 2004; Blight, 2005; Pollen-Bankhead & Simon, 2010)
Solar energy
![Page 6: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/6.jpg)
www.eng.chula.ac.th
![Page 7: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/7.jpg)
www.eng.chula.ac.th
Unsaturated soil mechanics
•• Soil water characteristic curve (SWCC)=> matric suction (u=> matric suction (u=> matric suction (uaa –––– uuuwuuw) vs. degree of saturation
•=> matric suction (u=> matric suction (u
• Shear strength: bfwanff uuc tantan bfwa uuu tan
Net normal stress
![Page 8: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/8.jpg)
www.eng.chula.ac.th
Root structures
Fan C.C. and Chen Y.W. (2010)
(a) Linden hibiscus (H-type); (b) Japanese Mallotus (VH-type); (c) Chinese tallow tree (V-type); (d) ironwood (VH-type); (e) white popinac (R-type)
![Page 9: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/9.jpg)
www.eng.chula.ac.th
Shear plane Shear plane –– root area ratio
bri iaD
1shear plane
1.2 n
r ri ii
c AA
Wu et al. (1979): Shear reinforcement was calculated from the sum of the forces required to break each individual, crossing the shear plane by where 1.2 is a correction factor for root orientation.
![Page 10: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/10.jpg)
www.eng.chula.ac.th
Objectives
• To understand the mechanism of vetiver root reinforcement for slope protection
Overall strength = Soil + Water + Root system + Interface
• To evaluate the shear strength contribution of the vetiver root for soil slope
• To demonstrate the role of vetiver root for slope stabilization
![Page 11: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/11.jpg)
www.eng.chula.ac.th
VetiverVetiver grass grass –– the Royal initiatives
• The The ChaipattanaChaipattana Foundation• Office of Office of Office of the the the Royal Development Office of
Projects the the the Royal Development Royal Development Office of Office of the
Projects Projects Projects Board (RDPB)• Land Development Department Land Development Department
(LDD)• Corporate social responsibility of Corporate social responsibility of
PTT Public company limited.
![Page 12: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/12.jpg)
www.eng.chula.ac.th
ChulalongkornChulalongkorn University Team• Prof. Prof. SuchedSuched LikitlersuangLikitlersuangLikitlersuang
Department of Civil Engineering, Department of Civil Engineering, Faculty of Engineering
•Faculty of EngineeringDr. Faculty of EngineeringFaculty of EngineeringDr. Dr. BoonratFaculty of EngineeringFaculty of Engineering
BoonratBoonrat LohwongwatanaDr. Dr. BoonratBoonratBoonrat LohwongwatanaLohwongwatanaDepartment of Metallurgical Engineering, Department of Metallurgical Engineering, Faculty of Engineering
•Faculty of EngineeringAssist. Prof. Faculty of EngineeringFaculty of EngineeringAssist. Prof. Assist. Prof. SirintraFaculty of EngineeringFaculty of Engineering
SirintraSirintra VannoAssist. Prof. Assist. Prof. SirintraSirintraSirintra VannoVannoDepartment of Landscape Architecture, Department of Landscape Architecture, Faculty of Architecture
•Faculty of ArchitectureDr. Faculty of ArchitectureFaculty of ArchitectureDr. Dr. SoamshineFaculty of ArchitectureFaculty of Architecture
SoamshineSoamshine BoonyanantaDr. Dr. SoamshineSoamshineSoamshine BoonyanantaBoonyanantaDepartment of Art, Music and Dance Education, Department of Art, Music and Dance Education, Faculty of Education
![Page 13: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/13.jpg)
www.eng.chula.ac.th
Sample preparation
Mr. Adithep Vangbunkong(Master student, Department of Civil Engineering)
Lowland Highland
![Page 14: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/14.jpg)
www.eng.chula.ac.th
Root observation
The average growth rate of vetiver roots = 30 cm/month (1 cm/day)
![Page 15: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/15.jpg)
www.eng.chula.ac.th
![Page 16: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/16.jpg)
www.eng.chula.ac.th
Image processing Image processing –– root area ratio
6 months highland 6 months highland vetivervetiver ––– 4.56%
6 months lowland 6 months lowland vetivervetiver ––– 3.36%
![Page 17: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/17.jpg)
www.eng.chula.ac.th
Direct shear tests
![Page 18: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/18.jpg)
www.eng.chula.ac.th
Large direct shear test
![Page 19: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/19.jpg)
www.eng.chula.ac.th
Results of direct shear tests
Test SpecimenShear strength
parametersIncreasing in
cohesion (kPa)
Standard direct shear test
Bare soil c = 6.8 kPa; = 22.8o -4 months old single
vetiver low landc = 7.7 kPa; = 29.7o 0.9
4 months old single vetiver high land
c = 13.7 kPa; = 28.8o 5.9
Large direct shear test
Bare soil c = 2.5 kPa; = 21.8o -6 months old group
vetiver low landc = 5.1 kPa; = 28.4o 2.6
6 months old group vetiver high land
c = 8.5 kPa; = 29.2o 6.0
![Page 20: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/20.jpg)
www.eng.chula.ac.th
![Page 21: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/21.jpg)
www.eng.chula.ac.th
![Page 22: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/22.jpg)
Study of vetiver root surfaces
3) Fine tip
8) Root cap
4) Knotted fine tip
5) Thick 2nd-order branch2) Thin 2nd-order branch1) 1st-order branch
7) 3rd-order branch
6) Long endfine tip
![Page 23: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/23.jpg)
www.eng.chula.ac.th
1) 1st-order branch
![Page 24: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/24.jpg)
www.eng.chula.ac.th
1) 1st-order branch
![Page 25: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/25.jpg)
www.eng.chula.ac.th
1) 1st-order branch
2) Thin 2nd-order branch
![Page 26: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/26.jpg)
www.eng.chula.ac.th
2) Thin 2nd-order branch
![Page 27: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/27.jpg)
www.eng.chula.ac.th
2) Thin 2nd-order branch
![Page 28: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/28.jpg)
www.eng.chula.ac.th
3) Fiber pullout
![Page 29: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/29.jpg)
www.eng.chula.ac.th
4) Knotted fine tip
![Page 30: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/30.jpg)
www.eng.chula.ac.th
5) Thick 2nd-order branch
![Page 31: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/31.jpg)
www.eng.chula.ac.th
7) Third-order branch
![Page 32: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/32.jpg)
www.eng.chula.ac.th
Vetiver root tip
![Page 33: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/33.jpg)
www.eng.chula.ac.th
![Page 34: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/34.jpg)
Adhesion at the InterfaceMicroscopic scale effect is important
![Page 35: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/35.jpg)
www.eng.chula.ac.th
![Page 36: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/36.jpg)
www.eng.chula.ac.th
Soil planted roots
A1_Elbow A2_Spindles
A3_EggShape Caught
A4_Cut section A1_Shaft
A1_Root tip lower down A1_Root tip A2_Spindles2
![Page 37: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/37.jpg)
www.eng.chula.ac.th
Sand planted roots
B1_Shaft B1_B2 Overlap B2_and Sand? B3_
B3_B1_Tip next to B2 B2_and Sand? B2_and Sand?
![Page 38: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/38.jpg)
www.eng.chula.ac.th
Root CapsA1_Root tip
A1_Root tip lower down
• Elongated cells ready to expand.
B1_Tip next to B2
![Page 39: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/39.jpg)
www.eng.chula.ac.th
Sample A vs B Comparison: Particles
B1_ShaftB2_and Sand?
• We observe both soil and sand particles embedded in the roots
• Particles can be differentiated from roots based on surface morphology
A3_EggShape Caught
A3_EggShape Caught 2x Zoom
![Page 40: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/40.jpg)
www.eng.chula.ac.th
Root Hairs and their spindles
• Filamentous tip growth is much more extensive in sample A (soil)
• Some root hairs are visible in sample B (and previous plug sample), but are significantly shorter and sparser
B3_
B3_A2_Spindles A2_Spindles2
![Page 41: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/41.jpg)
Root segment, pulled apart and surrounded
by soil
Sample F: Comparison of EM vs. LM
F – LM
(uncoated)
F – LM (coated)
Limited depth of
focus
Segment 1
(root
details
clearly
visibly
in EM)
F – EM
Fractur
e
surface
![Page 42: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/42.jpg)
Sample A fracture surface
Fracture sruface
Root hairs (invisible in LM)
![Page 43: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/43.jpg)
www.eng.chula.ac.th
Tensile delamination - root
![Page 44: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/44.jpg)
www.eng.chula.ac.th
Core fiber pull out
![Page 45: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/45.jpg)
www.eng.chula.ac.th
Findings
• Root hairs are important anchorage for Vetiver grass.
• Dense filamentous structures are substantially more developed in the soil-planted sample
• Vasculature is well-defined in cross-sectional samples.
• Future study of fractured roots and failure modes. A4_Cut section zoomed 2x
![Page 46: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/46.jpg)
Mechanics of roots and root hairs
![Page 47: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/47.jpg)
www.eng.chula.ac.th
Electron microscope observation
TRTR
Intact root
Deformed root
q
Shearzone
b
b
z
x
Interface friction Interface friction between soil and root (between soil and root between soil and root ((Graybetween soil and root GrayGray &
between soil and root between soil and root between soil and root & & & & Sotir
between soil and root between soil and root SotirSotir, 1996)
Root tip of Root tip of vetivervetiver grass. Root tip of Root tip of Root tip of Root tip of vetivervetivervetiver grass. grass. Width of the micrograph is Width of the micrograph is approximately 100 Width of the micrograph is Width of the micrograph is approximately 100 approximately 100 micron.
High density of root hairs. High density of root hairs. Low magnification image.
The root hairs are of the order of micron level and their interfacial area is contributing significantly to the friction due to their increased surface area.
This mechanism provides adhesion between root and soil during shear which could be directly linked cohesion term in Mohr-Coulomb failure criterion framework.
![Page 48: Laboratory Investigation of Vetiver Root Reinforcement … /6 S Likitlersuang... · Laboratory Investigation of Vetiver Root Reinforcement for Slope Protection ... Soil nail Live](https://reader031.fdocuments.in/reader031/viewer/2022022003/5aa28eea7f8b9a46238d3f5f/html5/thumbnails/48.jpg)
www.eng.chula.ac.th
Acknowledgement• The AUN/SEED-Net (JICA) • The Chaipattana Foundation• Office of the Royal Development Projects Board• The Sustainable Energy Foundation - PTT Co., LTD• Dr. Songkiert Tansamrit and P’ Yai – PTT Co., LTD• Dr. Pitayakon Limtong from LDD• Mr. Atichart Ruksajitr – The Chaipattana
Foundation