SLOPE STABILITY ANALYSIS WITH SOIL NAILS

REINFORCEMENT USING GEO-SLOPE / W PROGRAM

Final Project

To meet most requirement attain the degree civil engineering degree

Submitted by:

Thoriq Abdul Azis Rabbani

NIM : D100 144 007

CIVIL ENGINEERING DEPARTMENT

UNIVERSITAS MUHAMMADIYAH SURAKARTA

2021

ii

APPROVAL SHEET

SLOPE STABILITY ANALYSIS WITH SOIL NAILS REINFORCEMENT

USING GEO-SLOPE / W PROGRAM

Final Project

Submitted by:

Thoriq Abdul Azis Rabbani

Nim : D100 144 007

Approved by:

Anto Budi Listyawan, St., M.Sc

Nik: 913

Board of Examiners :

This Final Project is accepted as one of the requirements

to achieve Bachelor Degree of Civil Engineering

Surakarta, 17 February 2021

iii

FOREWORD

Assalamu’alaikum Wr.Wb

Alhamdulillah, praise to Allah SWT who has bestowed His grace and

guidance, so that the author can complete his final project entitled “SLOPE

STABILITY ANALYSIS WITH SOIL NAILS REINFORCEMENT USING

GEO-SLOPE / W PROGRAM” can be compiled. This final project is prepared as

a graduation requirement in the Civil Engineering Study Program,

Muhammadiyah University of Surakarta.

In the preparation of this final project the writer gets a lot of suggestions,

encouragement, guidance, and information from various parties. Therefore, with

all due respect and humility, please allow the writer to thank:

1. Mr. Sri Sunarjono, PhD as the dean of engineering faculty of universitas

muhammadiyah surakarta who has guided during the lecture period and

always provides a lot of useful advice for writers.

2. Mr. Mochamad Solikin, PhD as head of civil engineering of universitas

muhammadiyah surakarta who has provided knowledge during his lecture.

3. Mr. Anto Budi Listyawan, ST., MSc as the supervisor of this research,

gave lots of suggestions during lectures and was always patient with the

writer.

4. Mr.Agus Susanto ST., MT as lecturer and examiner of these research.

5. Ms Ir. Renaningsih MT. as lecturer and examiner of these research.

6. Mr. Budi Priyanto as lecturer and writer personal support.

7. All lecturer of civil engineering universitas muhammadiyah surakarta who

guide and provide new knowledge to writers.

8. Supardiyo and Supadmi as my parents who always helped and guided the

writer's life.

9. Yusron, Hafsah, Hanna, Muna and Iffah as families who help in the

development of the writer's social life.

10. Kannia who assisted the author in completing the research.

11. All friends who helped in the preparation of research.

iv

12. All parties that the author cannot mention.

The author realizes that this Final Project Report is still far from perfect, for

that constructive criticism and suggestions are still the authors hope. In

conclusion, the authors hope that this research can be useful for all of us.

Surakarta, ...................2021

Author

v

DECLARATION OF AUTHORSIP

The undersigned below

Name : Thoriq Abdul Azis Rabbani

NIM : D100 144 007

Faculty/Depatment : Engineering/Civil Engineering

Title : SLOPE STABILITY ANALYSIS WITH SOIL NAILS

REINFORCEMENT USING GEO-SLOPE / W

PROGRAM

Declare that this final project is made and presented by the author, except for

quotations and summaries that have been explained by the author from all

sources. If later found in this thesis there is plagiarism, the author is willing to

accept any legal consequences that may be imposed on the author.

Surakarta, 4 Mei 2021

Author,

Thoriq Abdul Azis Rabbani

vi

MOTTO

“Urip Iku Urup”

“Memayu Hayuning Bawana, Ambrasta Dur Hangkara”

“Sura Dira Jaya Jayaningrat, Lebur Dening Pangastuti”

“Ngluruk Tanpa Bala, Menang Tanpa Ngasorake, Sekti Tanpa Aji-aji, Sugih

Tanpa Bandha”

“Datan Serik Lamun Ketaman, Datan Susah Lamun Kelangan”

“Aja Gumunan, Aja Getunan, Aja Kagetan, Aja Aleman”

“Aja Ketungkul Marang Kalungguhan, Kadonyan Lan Kemareman”

“Aja Kuminter Mundak Keblinger, Aja Cidra Mundak Cilaka”

“Aja Milik Barang Kang Melok, Aja Mangro Mundak Kendho”

“Aja Adigang, Adigung, Adiguna”

~Dasa Pitutur Sunan Kalijaga~

vii

TABLE OF CONTENT

APPROVAL SHEET ....................................................................................... ii

FOREWORD ................................................................................................... iii

DECLARATION OF AUTHORSIP ................................................................ v

MOTTO ........................................................................................................... vi

TABLE OF CONTENT ................................................................................... vii

LIST OF TABLE ............................................................................................. x

LIST OF PICTURE ......................................................................................... xi

LIST OF SYMBOLS AND CONTRACTION ................................................ xiii

ABSTRAK ....................................................................................................... xvi

ABSTRACT ..................................................................................................... xvii

CHAPTER I INTRODUCTION ............................................................... 1

A. Background .......................................................................................... 1

B. Statement Of The Research .................................................................. 1

C. Research Objectives ............................................................................. 2

D. Research Benefits ................................................................................. 2

E. Problem Limitation .............................................................................. 2

F. Authenticity of Research ...................................................................... 3

CHAPTER II LITERATURE REVIEW .................................................... 5

A. Soil ....................................................................................................... 5

B. Slope Stability ...................................................................................... 5

C. Ordinary Method Of Slices .................................................................. 8

D. Soil Nails .............................................................................................. 9

E. Geostudio ............................................................................................. 17

CHAPTER III THEORITICAL REVIEW ................................................. 19

A. Ordinary Method of Slices ................................................................... 19

B. Soil Nail Analysis ................................................................................. 20

1. External stability analysis.............................................................. 21

2. Internal stability analysis ............................................................... 29

viii

CHAPTER IV THE RESEARCH METHOD .............................................. 31

A. Slope modeling and nail parameters. ................................................... 31

1. Slope modeling .............................................................................. 31

2. Data parameter nails ...................................................................... 32

3. Minimum safety factor of nailed slope ......................................... 32

B. Road structure planning ....................................................................... 33

1. Load on slope ................................................................................ 33

2. Highway pavement ........................................................................ 34

3. Vehicle .......................................................................................... 34

C. Modeling with the Geoslope program .................................................. 35

1. Initial Setting ................................................................................. 35

2. Worksheet Settings ........................................................................ 36

3. Drawing Slope Geometry .............................................................. 38

4. Defines Soil Parameters ................................................................ 39

5. Drawing The Slip Surface ............................................................. 40

6. Draw The Surcharge Load ............................................................ 42

7. Drawing Soil Nailing Reinforcement ............................................ 42

8. Problem Solving ............................................................................ 43

D. Research Stage ..................................................................................... 44

CHAPTER V ANALYSIS AND DISCUSSION ...................................... 45

A. Road Structure Planning ....................................................................... 45

1. Load Calculation ........................................................................... 45

B. Slope Stability Analysis Without Reinforcement ................................ 46

1. Manual analysis using fellenius method ....................................... 46

2. Geoslope Analysis Without Surcharge ......................................... 50

3. Geslope analysis with surcharge ................................................... 51

C. Soil Nails Analysis ............................................................................... 53

1. Global stability failure ................................................................... 53

2. Sliding stability failure .................................................................. 58

3. Bearing failure ............................................................................... 59

4. Tensile strength and pullout failure ............................................... 60

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CHAPTER VI CONCLUSION AND SUGGESTION ................................ 62

A. Conclusion ............................................................................................ 62

B. Suggestion ............................................................................................ 63

BIBLIOGRAPHY ............................................................................................ 64

Appendix .......................................................................................................... 65

x

LIST OF TABLE

Table I.1 Specific gravity, water content, and soil weight ......................... 3

Table I.2 Cohesion and friction angle of soil ............................................. 3

Table I.3. The similarities and differences from some similar studies ....... 4

Table II.1 Treaded bar properties [ASTM A615, GRADES 420 and525

MPa (60 and 75 ksi)] .................................................................. 11

Table III.1 Typical values of modulus of subgrade reaction (ks) for

different types of soils ................................................................. 24

Table III.2 Ultimate bond strength ................................................................ 25

Table III.3 Capacity factor of terzaghi .......................................................... 28

Table IV.1 Specific gravity, water content, and soil weight ......................... 31

Table IV.2 Cohesion and friction angle of soil ............................................. 32

Table IV.3 Minimum safety factor of nailed slope ....................................... 33

Table V.1 Table of slice weight on slip surface without surcharge ............. 47

Table V.2 Table of slice weight on slip surface with surcharge .................. 49

Table V.3 The results of manual slope calculations .................................... 56

Table V.4 The results of manual calculation of tensile and pullout safety

factor ........................................................................................... 61

xi

LIST OF PICTURE

Figure I.1 Cross section of slope that will be analyzed (in meter) ............ 3

Figure II.1 Picture of a natural slope .......................................................... 6

Figure II.2 Picture of artificial slope using soil nailing ............................. 6

Figure II.3 Earth dam at lake arenal dam – costa Rica ............................... 7

Figure II.4 Types of slope landslide ........................................................... 8

Figure II.5 Ordinary method of slice .......................................................... 9

Figure II.6 Illustration. Main components of a solid bar soil nail and

associated wall facing. Modified after Porterfield et al.

(1994) ....................................................................................... 10

Figure II.7 Typical soil nail wall construction sequence ............................ 13

Figure II.8 Roadway cut supported with soil nails ..................................... 15

Figure II.9. Road Widening Under Existing Bridge (source NHI14007,

2015) ........................................................................................ 16

Figure III.1 Forces worked at the slope ....................................................... 19

Figure III.2: Principal Modes of failure of soil nail wall systems ................ 21

Figure III.3 Force acting on the wedge method ........................................... 22

Figure III.4 Correlation chart for sand soils (source: API, 1987) ................ 24

Figure III.5 Sliding stability of a soil nail wall. .......................................... 27

Figure III.6 Nail pull-out failure. ................................................................. 29

Figure III.7 Schematic location of soil nails maximum tensile forces ........ 30

Figure IV.1 Cross section of slope that will be analyzed (in meter) ............ 32

Figure IV.2 Vehicle load distribution ( Giroud and Noiray, 1981) ............. 34

Figure IV.3 Windows of determining analysis method ............................... 35

Figure IV.4 The slipsurface windows .......................................................... 36

Figure IV.5 The number of slice window .................................................... 36

Figure IV.6 Worksheet window ................................................................... 37

Figure IV.7 Scaling and unit worksheet window ......................................... 37

Figure IV.8 The worksheet coordinate window ........................................... 38

xii

Figure IV.9 Slope profile drawing window ................................................. 38

Figure IV.10 Soil properties window ............................................................. 39

Figure IV.11 Soil layering window ................................................................ 40

Figure IV.12 Grid and radius slip surface window ........................................ 41

Figure IV.13 Exit and entry slip surface window .......................................... 41

Figure IV.14 Surcharge load window ............................................................ 42

Figure IV.15 Soil nailing window .................................................................. 42

Figure IV.15 Soil nailing window .................................................................. 42

Figure IV.16 Soil nailing design .................................................................... 43

Figure IV.17 Solve manager window ............................................................ 43

Figure IV.18 Flow Chart of Soil Nails Reinforcement .................................. 44

Figure V.1 Vehicle load distribution .......................................................... 45

Figure V.2 Cross section of slope withour surcharge ................................. 47

Figure V.3 Cross section of slope with surcharge ...................................... 48

Figure V.4 The results of the analysis of slope landslides in the analysis

program (grid and radius) without surcharge load ................... 50

Figure V.5 The results of the analysis of slope landslides in the analysis

program (exit and entry) without surcharge load ..................... 51

Figure V.6 The results of the analysis of slope landslides in the analysis

program (grid and radius) with surcharge load ........................ 52

Figure V.7 The results of the analysis of slope landslides in the analysis

program (exit and entry) with surcharge load .......................... 53

Figure V.8 Sketch of slope with reinforcement against global stability

with a angle of slope 70, nail inclination 10, and a distance of

1m between the nails. ............................................................... 54

Figure V.9 Length of Le on slope ............................................................... 56

Figure V.10 Results of slope analysis landslides in the analysis program

(grid and radius) ....................................................................... 57

Figure V.11 Results of slope analysis landslides in the analysis program

(entry and exit) ......................................................................... 58

Figure V.12 Slope stability against sliding in soil nailing reinforcement .... 58

xiii

LIST OF SYMBOLS AND CONTRACTION

R Radius of circle – the field of an avalanche.

n The number of slices

Wi Weight mass of land sliced into – i

F Safety factor

c Soil cohesion (kN/m2)

La Length of curvature circle on sliced into-i (m)

Ni Effective normal force (kN)

FSG Safety factor of global stability

C Cohesion

Lf Length of the failure plane

W Weight of sliding mass

Q Dead load on the slope

Φ Internal friction angle

α Inclination of the failure plane

i Nail inclination

β Slope angle

ΣTi Total allowable tensile strength

ΣVi Total allowable shear force

V Allowable shear strength of nail bars

T Allowable tensile strength of nail bars

Rn Tensile carrying capacity of nail bars

V Passive shear strength of soil

D,d Diameter of nail bars

V Passive shear strength of soil

D Diameter of nail bars

Lo Length of the distribution ∜(4EI/KsD)

EI Stiffness of nail bars

Ks Lateral modulus reaction of soil

xiv

Pmax Passive stress that limited become half of ultimate stress

Vmax Allowable shear strength

Tmax Allowable tensile strength

Rc Shear strength capacity of nail bars

H Wall height

ΔH Slope rise up to bench (if present)

β Backslope angle

βeq Equivalent backslope angle [for broken slopes βeq = tan-1 (ΔH/H),

for infinite slopes βeq = β]

α Face batter angle

θ Inclination of wall face from horizontal (i.e., θ= α + 90 ֯ )

cb Soil cohesion strength along the base

Bl Length of the horizontal failure surface where cb is effectively

acting

W Weight of nail block

QD Permanent portion of total surcharge load QT

ɸ’b Effective angle of internal friction of the base (remolded or

residual values may be needed if the significant movement takes

place)

ɸ’ Effective friction angle of soil behind soil nail block

δ Wall-soil interface friction angle [for broken slope, δ = βeq, for

infinite slope, δ = βeq]

γ Total unit weight of soil mass

H1 Effective height over which the earth pressure acts [ H1 = H + (B +

tan α) tan βeq]

KA Active earth pressure coefficient for soil behind the soil nail wall

system

Nc, Nγ Bearing capacity factor (table III.3)

γ Unit weight of soil behind the wall

Heq, H Wall height

Qu Ultimate bond strength

xv

DDH Average or effective diameter of the drill hole

LP Length of the bar behind the failure plan

σh Horizontal stress

Sv Vertical spacing

Sh Horizontal spacing

Ka Coefficient of active earth pressure

γ Unit weight of soil

z Depth of embedded nail

fy Nail bar yield strength

xvi

ABSTRAK

Pergerakan tanah atau massa batuan merupakan peristiwa geologis yang

disebakan ketidakstabilan atau kegagalan pada lereng. Masalah ini harus diatasi

secepat mungkin ini berbahaya dan merugikan lingkungan sekitar. Penelitian ini

dilaksanakan pada Desa Pensil Jatikuwung Kecamatan Karanganyar Kabupaten

Jatipuro dan jenis tanahnya tanah liat. Penelitian ini bersifat teoritis yang

dimodelkan dengan bantuan program geoslope, dan tidak dilakukan permodelan

fisik dilaboratorium. Tujuan dari penelitian ini adalah mengetahui faktor

keamanan sebelum longsor dan merencanakan perkuatan lereng.

Hasil analisis menggunakan program geoslope geoslope/w 2012, kemudian

dibandingkan dengan perhitungan manual menggunakan metode fellenius tanpa

perkuatan dan metode baju (wegde) pada lereng dengan perkuatan. The material

of nailed slope is using nai bars with the diameter of 29 mm and the grade is 75

ksi or 517 mpa with final designof slope incination is 70°.

Dari hasil penelitian diperoleh faktor aman dari geoslope adalah 0.873 (grid

and radius), 0.815 (exit and entry) dan 0.894 dari perhitunga manual tanpa beban

merata dan dengan beban merata diperoleh faktor aman dari geoslope adalah

0.557 (grid and radius), 0.634 (exit and entry) dan 0.544 dari perhitungan manual

yang berarti rawan longsor. Keruntuhan lereng global (FSG) adalah 2.116

(manual) dan dengan grid and radius geoslope 2.019, entry and exit 1.915> 1.5

(aman), Stabilitas geser (FSSL) adalah 6.996> 1.5 (aman), Stabilitas daya dukung

tanah (FSH) adalah 3.001 . > 3,0 (aman), Stabilitas putus tulangan (FST) 7.799>

1,8 (aman) dan stabilitas cabut tulangan(FSP) 12.519. > 2.0 (aman)

Keywords : fellenius method, geostudio program, soil nails, landslide, slope

stability

xvii

ABSTRACT

The movement of soil or rock mass is a geological event that is caused by

instability or failure of the slope. This problem must be addressed as soon as

possible. It is dangerous and harfmful to the surrounding environment. This

research was conducted at the Pencil Village of Jatikuwung in the subdistrict of

Karanganyar district of Jatipuro and the type of soil is clay. This research is

theoretical, which is modeled with the help of the geoslope program, and physical

modeling is not carried out in the laboratory. The purpose of this research was to

determine the safety factor before landslides and to plan slope reinforcement.

The results of the analysis used the geoslope / w geoslope program 2012,

then compared with manual calculations using the fellenius method without

reinforcement and the wegde method on reinforced slopes. The material of nailed

slope is using nail bars with the diameter of 29 mm and the grade is 75 ksi or 517

mpa with final design of slope incination is 70 °.

From the results of the study, the safe factor from geoslope program is

0.873 (grid and radius), 0.815 (exit and entry) and 0.860 with manual calculation

without surcharge load and with surcharge load, the safe factor from geoslope

program is 0.557 (grid and radius), 0.634 (exit and entry) and 0.525 with manual

calculation which means prone to landslide. Global stability failure (FSG) is 2.116

(manual) and with geoslope grid and radius is 2.019, exit and entry 1.915 > 1.5

(safe), Sliding stability failure (FSSL) is 6.996 > 1.5 (safe), Bearing stability

(FSH) is 3.001 . > 3.0 (safe), Nail tensile strength failure (FST) is 7.799> 1.8

(safe) and nail pullout stability (FSP) is 12.519 > 2.0 (safe).

Keywords : fellenius method, geostudio program, soil nails, landslide, slope

stability