mini project

1. DESIGN AND ANALYSIS OF MSE WALL
AT ROB KOTTAYAM
Presented by: Guided By:
Sruthi Raj pk. Prof. Anil Kumar PS
Roll no: 07

2. • Design and analysis of Mechanically stabilized earth retaining wall of ROB Kottayam.
Using MSEW Software.
• Provided Initial height of the wall 7m with modular concrete panel facing
• Follows FHWA-NHI-10-024 Design guidelines
• External stability check - Direct sliding, Bearing Capacity and Eccentricity can be
assessed using Ka based on Coulomb’s lateral earth pressure.
• Internal stability check – Pull out resistance, connection strength, Reinforcement tension
resistance.
INTRODUCTION

3. LITERATURE REVIEW
Author
Year of
publicati
on
Journal name Description
1.Joseph E Bowler 1988 Foundation analysis and design
• The mechanically reinforced earth wall uses the principle of
placing reinforcing into the backfill using devices such as metal
strips and rods, geotextile strips and sheets and grids, or wire grids
• Basic 3 components of a reinforced retaining wall is earth fill,
facing unit and Reinforcement
2.Christopher Barry
R.
2009 Design and Construction of
Mechanically Stabilized Earth Walls
and Reinforced Soil Slopes – Volume
I:FHWA-NH-10-024
• Mechanically Stabilized Earth Walls (MSEWs) and Reinforced
Slopes (RSSs) are cost effective soil-retaining structures that can
tolerate much larger settlements than reinforced
• placing tensile reinforcing elements (inclusions) in the soil, the
strength of the soil can be improved significantly.
• Use of a facing system to prevent soil raveling between the
reinforcing elements allows very steep slopes and vertical walls to
be constructed safely.

4. Author
Year of
publicati
on
Journal name Description
3.Armin stuedlein 2010 Design and Performance of a 46-m-
High MSE wall
• Geotechnical instrumentation, including wall surveys,
inclinometer installations with sondex settlement rings,
piezometers, and strain gages on reinforcing strips, provides
information required to verify performance of the wall relative to
design
• Selected steel strip reinforcement in order to limit and extend
embankment fill .
4.Michael Dobie 2013 Reinforced Soil Retaining Walls – An
Outline of Design Methods and
Sources of Conservatism
• Conservatism can be reduced by using a method of calculation for
internal stability which models likely modes of failure as closely
as possible, and requires as few assumptions as possible to make
the calculation.
• Soil tests are required to define the fill shear strength and unit
weight

5. Author
Year of
publicati
on
Journal name Description
5.Haresh D Golakiya 2015 Design and behaviour of
Mechanically stabilized earth wall
• Angle of internal friction Ø is the most important of all other
parameters as the basic principal of mechanically stabilization of
earth depends on it.
• Length of reinforcement layers increases as height of wall
increases. Design strength of reinforcement and vertical spacing
between two reinforcements are also main factors
6.Richard J Bathurst 2016 The influence of facing stiffness on
the performance of two geosynthetic
reinforced soil retaining walls
• Stiff facing in a reinforced soil wall is a structural component that
can lead to significant reductions in reinforcement loads compared
to flexible facing systems.
7.Soroush Nazarin 2017 Estimation of Maximum Lateral
Displacement of the Back to Back
Mechanically Stabilized Earth Walls
• Back to back mechanically stabilized earth walls (MSEWs) are
the structures usually used in two sides of bridge abutments and
ramps

6. Author
Year of
publicati
on
Journal name Description
8.Ratnesh ojha 2021 Study of Geosynthetic Reinforced
Retaining Wall under Various
Loading
• Reinforcement in the soil can be used to enhance the behavior of
retaining walls under seismic loading in terms of improved overall
stability of the structure.
• In Case of high retaining wall, tiered walls are preferred over a
single height retaining wall due to their cost-effectiveness
9.Haitham H. Muteb 2021 Mechanically Stabilized Earth MSE
Walls Applications
• Reinforcing structure and the facing units serve as a supporting
system
• The MSE approach is used to solve the infrastructure problems
that are faced in transportation programs.
10. Hariprasad
chennarupa
2022 The analysis and design of MSE wall
by considering variation of friction
angle of backfill material along the
depth
• (MSE)structures are done by using various types of
reinforcements (coir fiber, metal strips, and geosynthetic
materials).
• Angle of shearing resistance between reinforcement and backfill
plays an significant role in the stability and serviceability of MSE
walls.

7. MECHANICALLY STABILIZED EARTH WALL
• A Mechanically Stabilized Earth (MSE) retaining wall is a composite structure consisting
of alternating layers of compacted backfill and soil reinforcement elements, fixed to a wall
facing.
• The stability of the wall system is derived from the interaction between the backfill and
soil reinforcements, involving friction and tension.
• The wall facing is relatively thin, with the primary function of preventing erosion of the
structural backfill. The result is a coherent gravity structure that is flexible and can carry a
variety of heavy loads.

8. • Benefits of MSE Walls:
• Flexibility to accommodate high differential settlement
and several feet of total settlement
• Bearing pressure is distributed over a wide foundation
area
• Extreme wall heights can be achieved
• Extreme loads can be carried (bridge abutment footings,
cranes)
• High resistance to seismic ground movement and other
dynamic forces
• Free-draining, due to granular backfill and open panel
joints

9. MSEW SOFTWARE
• Program MSEW+ is an interactive, graphically rich program, allowing the user to easily
explore various design options or conduct forensic analysis.
• Use of MSEW+ must be licensed. This device is provided with the software and it
constitutes a license.
• It enables the designer to conduct comprehensive analysis, including internal, external and
global stability.

10. METHODOLOGY
Evaluation of test results and
bore log data
Design of MSE wall
External and Internal stability
analysis in MSEW Software

11. FIELD INVESTIGATION
• The proposed site was situated at caritus Kottayam district
• The program of soil investigation consisting boring which was carried out to a depth of
22.3 m
• Borehole was terminated at a depth of 22.3m

12. BOREHOLE LOACATION

13. LAB RESULTS

14. CODAL PROVISIONS
IRC 116-2018
Base width 0.6 to 0.75H ( For height 1 to 6m )
0.55 to 0.65H (above 6 to 10m)
Batter angle 3° to 6° with vertical angle
IRC SP 102 2014
Min length 0.75H or 3m

15. DESIGN OF MSE WALL
1. DESIGN WALL GEOMETRY
Design is carried out as per FHWA ,IRC 116:2018 , IRC SP 102:2014
Height of the wall ,H = 8m
Wall batter , 𝜔 =4°
Back slope of the wall , 𝛽=0 (Horizontal backslope)
Assuming length of reinforcement =7 m (Min length =0.7H or 3m)

16. 2. ENGINEERING PROPERTIES OF SOIL
𝜸(𝑲𝑵/𝒎𝟑) ∅( 𝑫𝒆𝒈𝒓𝒆𝒆) C(𝑲𝑵/𝒎𝟐)
Reinforced soil 20 34 0
Retained soil 18 30 0
Foundation soil 20 34 0

17. L = 6 m
H = 7m

18. 3. DESIGN LOAD
Dead load , 𝑞𝐷 = 12 KPa
Live load , 𝑞𝐿 = 24 Kpa
4. COEFFICIENTS OF LATERAL EARTH PRESSURES
Coefficient of Active earth pressure of reinforced soil, 𝑘𝑟 = 𝑡𝑎𝑛2
(45-
34
2
)=0.282
Coefficient of Active earth pressure of retained soil , 𝑘𝑎𝑏 = 𝑡𝑎𝑛2(45-
30
2
)= 0.333

19. 5. EXTERNAL STABILITY ANALYSIS
 Check for Sliding
Sliding force , Fs = 0.5 𝑘𝑎𝑏* 𝛾* 𝐻2 + 𝑘𝑎𝑏* (𝑞𝐷 + 𝑞𝐿 )* H
= 287 KN/m
𝜇 = tan(2
3 ∗ 30)=0.364
Resisting force , 𝐹𝑟=𝜇 { (𝛾*H*L) +(𝑞𝐷 *L)}
= 439 KN/m
Factor of safety against sliding =
𝐹𝑟
𝐹𝑠
=1.53> 1.5
Hence safe

20.  Check for overturning
Overturing moment , 𝑀0 = 0.5 𝑘𝑎𝑏* 𝛾* 𝐻2
∗ (
𝐻
3
)+ 𝑘𝑎𝑏* (𝑞𝐷 + 𝑞𝐿 )* H*(H/2)
= 895 KN-m/m
Resisting moment, 𝑀𝑟 = 𝛾*H*L*
𝐿
2
+𝑞𝐷 *L*
𝐿
2
= 4214 KN-m/m
Factor of safety against overturing =
𝑀𝑟
𝑀0
=4.7 > 2
Hence safe

21.  Check for Bearing capacity
𝑅𝑣 = 𝛾∗H∗L + (𝑞𝐷 + 𝑞𝐿 )* L
= 1372 KN/m
e =
𝑀0
𝑅𝑣
= 0.65 < 𝐿
6=1.16
Hence safe
𝜎𝑉𝐵 =
𝑅𝑣
𝐿−2𝑒
= 241 𝐾𝑁/𝑚2
Allowable bearing capacity was found out by using Meyerhof’s by considering the foundation as
strip footing. For the MSE wall the shape factor, depth factor, and inclination factor are taken as
unity. Considering general shear failure. C=0

22. As per IS 6403: 1981
As per Table 1 bearing capacity factor of IS 6403: 1981
For ɸ = 34° 𝑁𝑞 = 30.32, 𝑁𝛾 = 42.90
W’=0.5 (Water table at the base)
B=L-2e =6.7m
Ultimate bearing capacity , = 𝐶𝑁𝑐+ 𝛾 𝐷𝑓 𝑁𝑞+ 0.5 𝛾 𝐵𝑁𝛾 W’
= 2043 𝐾𝑁/𝑚2
Net safe bearing capacity , 𝑄𝑛𝑠 =
𝑄𝑢
2.5
= 817.2 𝐾𝑁/𝑚2
𝜎𝑉𝐵 <
Hence safe
𝑄𝑢

23. 4. Seismic External Stability Analysis
As per IS 1893-2002
Seismic zone: III and Zone Factor, Z = 0.16
Importance Factor, I = 1.5 (Table 6)
Response reduction factor, R = 3 (Table 7)
Spectral acceleration coefficient,
𝑆𝑎
𝑔
= 1 from chart
Base Acceleration, α =
𝑍𝐼
2𝑅
𝑆𝑎
𝑔
= 0.04
Average accelaration coefficient of soil as per FHWA
α𝑚 =(1.45 – α)*α = 0.0564
Lateral thrust from backfill , 𝑃𝐴𝐸 = 0.375∗ α𝑚 * 𝛾 *𝐻2
= 24 KN/m
acts at 0.6H from base

24. Ineria force of the soil in RE block due to self weight , 𝑃𝐼𝑅 = 0.5∗ α𝑚 * 𝛾 *𝐻2
=36.09 KN/m acts at 0.5H from base.
Total seismic force , 𝑃𝑇 = 0.5𝑃𝐴𝐸 + 𝑃𝐼𝑅
= 60.59 KN/m
 Check for sliding
Total lateral force , Fs = Total seismic +sliding force
=60.59+ 287
=347.59KN/m
Resisting force , 𝐹𝑟 = 439 KN/m
Factor of safety against sliding =
𝐹𝑟
𝐹𝑠
= 1.27 > 75% of 1.5 = 1.12

25.  Check for overturning
Overturning moment , 𝑀0 = 895+ 𝑃𝐼𝑅*0.5H+ 𝑃𝐴𝐸 ∗ 0.65𝐻
= 1164 KN-m/m
Resisting moment , 𝑀𝑟 = 4214 KN-m/m
Factor of safety against overturning =
𝑀𝑟
𝑀0
=3.6 > 75% of 2 = 1.125
Hence safe
 Check for bearing capacity
𝑅𝑣 = 1372 KN/m
e =
𝑀0
𝑅𝑣
= 0.84 < 𝐿
6=1.16
Hence safe
𝜎𝑉𝐵 =
𝑅𝑣
𝐿−2𝑒
= 258 KN/𝑚2
𝜎𝑉𝐵 <
Hence safe

26. 6. INTERNAL STABILITY ANALYSIS
 The facing of the MSE wall is a gabion structure. The thickness of the gabion unit is 0.8. That is the
vertical spacing of the reinforcement layer is taken as 0.8m .
 Geogrid is selected as the reinforcement and the ultimate tensile strength of the geogrid is 150 KN/m.
 𝑅𝐹𝐼𝐷= 1.3 (Table 3-9. Installation Damage Reduction Factors, FHWA)
 𝑅𝐹𝐶𝑅 = 2 (clause 3.5.2.c Creep Reduction Factor, FHWA)
 𝑅𝐹𝐷 = 1.3 (Table 3-11. Durability (Aging) Reduction Factors for PET, FHWA)

27. No of reinforcement layer = 8/0.8 =10
Internal stability
𝒑𝒉 =𝛾 ∗ 𝑧 ∗ 𝑘𝐴 + 𝑞𝑠 * 𝑘𝐴
=20*z*0.282 + 36*0.282
=5.64 *z +10.152
1) For geogrid vertical spacing
 𝑇𝑢 = 150 KN/m
 𝑇𝑎𝑙𝑙𝑜𝑤𝑎𝑏𝑙𝑒 =
𝑇𝑈𝑙𝑡
𝑅𝐹
=
𝑇𝑈𝑙𝑡
𝑅𝐹𝐼𝐷∗𝑅𝐹𝐷∗𝑅𝐹𝐶𝑅
=
150
1.3∗2∗1.3
= 44.38 KN/m
 𝑇𝑑𝑒𝑠𝑖𝑔𝑛 =31.7 KN/m

28. 𝑇𝑑𝑒𝑠𝑖𝑔𝑛 =
ℎ ∗𝒑𝒉
𝐶𝑟
h =
25.36
5.64 ∗z +10.152
Max depth for h =1m ,z= 2.69m
Max depth for h= 0.5m , z= 7.19m
2)Embedment length of geogrid layers
2𝑐𝑖𝑐𝑟𝐿𝑒𝑝0tan∅ = 𝑝ℎ h 𝐹𝑠
Le =
(0.52 𝑧+0.94)ℎ
𝑧
Equation for 𝐿𝑅 = (H-z) tan (45-
∅
2
)
= 4.25 -0.53z

29. From the above relationship the spacing of geogrid layers and their length are given below
Layer no Depth
(m)
Spacing(h)
(m)
Le
(m)
Le (min)
(m)
𝐿𝑅
(m)
L (cal)
(m)
L(req)
(m)
1 0 0 0 1 4.25 5.25 7
2 0.8 0.8 1.356 1 3.83 4.83 7
3 1.6 0.8 0.886 1 3.40 4.40 7
4 2.4 0.8 0.729 1 2.98 3.98 7
5 3.2 0.8 0.651 1 2.55 3.55 7
6 4 0.8 0.604 1 2.13 3.13 7
7 4.8 0.8 0.573 1 1.71 2.71 7
8 5.6 0.8 0.550 1 1.28 2.28 7
9 6.4 0.8 0.533 1 0.86 1.86 7
10 7.2 0.8 0.520 1 0.434 1.434 7

30. EXTERNAL STABILITY
 Check for sliding
𝐹𝑟
𝐹𝑠
= 1.53> 1.5
Hence safe
 Check for overturning
𝑀𝑟
𝑀0
= 4.7 > 2
Hence safe
 Check for bearing capacity
e =
𝑀0
𝑅𝑣
= 0.84 < 𝐿
6=1.16
Hence safe
𝜎𝑉𝐵 =
𝑅𝑣
𝐿−2𝑒
= 258 KN/𝑚2
𝜎𝑉𝐵 <
Hence safe

31. RESULTS & CONCLUSIONS

38. REFERENCES
• PC varghese ‘Foundation engineering’ ,2012.
• FHWA-NHI-10-024 ‘Design and Construction of Mechanically Stabilized Earth Walls
and Reinforced Soil Slopes’ ,Volume I- 2009.
• IS 6403 (1981): Code of practice for determination of bearing capacity of shallow
foundation.

39. THANK YOU