ENHANCING STABILITY OF SLOPE USING SOIL NAILINGeprints.utm.my/id/eprint/79444/1/NorshazwinaJohariMFKA2016.pdf · dan paras air bawah tanah. Kemudian, pelbagai sudut kecerunan soil

ENHANCING STABILITY OF SLOPE USING SOIL NAILING

NORSHAZWINA JOHARI

UNIVERSITI TEKNOLOGI MALAYSIA

ENHANCING STABILITY OF SLOPE USING SOIL NAILING

NORSHAZWINA JOHARI

A project report submitted in partial fulfilment of the

requirements for the award degree of

Master of Engineering (Geotechnics)

Faculty of Civil Engineering

Universiti Teknologi Malaysia

DECEMBER 2016

iii

To my husband.

Muhammad Naim Rahim

To my parents.

Johari Sabani

Siti Hamimah Selamat

My teachers.

My siblings.

My friends.

iv

ACKNOWLEDGMENT

Firstly, I would like to express my sincere gratitude and love to my dear

husband, Mr. Muhammad Naim Rahim, my dear parents, Mr. Johari Sabani and Siti

Hamimah Selamat, and the entire family for consistent love, support, encouragement and

guidance shown to me during the course of my study.

I would like to acknowledge everyone who had assisted me in the creation of

this writing especially my supervisor, Dr. Nazri Ali. Your invaluable assistance,

patience and insights are truly appreciated.

I would also like to express my gratitude to my family for their generous

support that had provided me with the strength and motivation in finishing my

master’s degree.

Not to mention, my colleagues, who had helped me through thick and thin

during this whole programme. Also my gratitude to all the folks who had took a part

in realizing the completion of this project.

Thank you.

v

ABSTRACT

Slope stability issue becomes one of the main problems in construction

industry due to nature of the topography and the weather conditions in Malaysia.

Various of technique can be applied for slope strengthening. One of the effectiveness

and economic system is application of soil nail in slope surface. The objectives of the

study were; i) to determine the effect of shear strength parameters and groundwater

table on slope stability, ii) to determine the effect of soil nailing on slope stability,

iii) to determine the optimum angle of nail inclination and slope degree with higher

FOS, iv) to install/apply soil nail for slope stability improvement in the case study.

Various simulation modeling and various parametric study were applied in this study

such as slope angles, Ø cohesion, c internal angle of friction, ф and groundwater level.

Then, various inclinations of soil nailing were applied in order to find optimum angle of

soil nailing for strengthening slopes. Slope/W software was used in the slope stability

analysis. All the results then were tabulated and recorded in the report. Based on the

analysis, it shows that the shear strength parameters affect the stability of slopes by

given a highest factor of safety. Soil nailing also will enhance the stability of slope by

increasing in factor of safety. The soil nailing would produce highest factor safety when

an optimum inclination angle of nails is applied.

vi

ABSTRAK

Isu kestabilan cerun menjadi salah satu masalah utama dalam industri

pembinaan kerana sifat topografi dan keadaan cuaca di Malaysia. Pelbagai teknik

boleh digunakan untuk pengukuhan cerun. Salah satu keberkesanan dan sistem

ekonomi adalah pengukuhan tanah di permukaan cerun. Objektif kajian ini ialah; i)

untuk menentukan kesan parameter kekuatan ricih dan air tanah terhadap kestabilan

cerun, ii) untuk menentukan kesan soil nailing terhadap kestabilan cerun, iii) untuk

menentukan sudut optimum kecerunan soil nail dan darjah cerun dengan FOS lebih

tinggi, iv) memasang / soil nailing untuk penambahbaikan kestabilan cerun dalam

kajian kes. Pelbagai model simulasi dan pelbagai kajian parametrik telah digunakan

dalam kajian ini seperti sudut cerun, Ø kejelekitan tanah, c sudut geseran dalaman, ф

dan paras air bawah tanah. Kemudian, pelbagai sudut kecerunan soil nailing telah

digunakan untuk mencari sudut optimum soil nailing untuk mengukuhkan cerun.

Slope/W perisian telah digunakan dalam analisis kestabilan cerun. Semua keputusan

kemudian telah dijadualkan dan direkodkan dalam laporan itu. Berdasarkan analisis,

ia menunjukkan bahawa parameter kekuatan ricih mempengaruhi kestabilan cerun

dengan memberikan faktor keselamatan (FOS) tertinggi. Kaedah soil nailing juga

akan meningkatkan kestabilan cerun dengan meningkatkan dalam faktor keselamatan

(FOS). Kaedah soil nailing ini juga akan menghasilkan faktor keselamatan (FOS)

tertinggi apabila sudut kecerunan optimum soil nailing digunakan.

vii

TABLE OF CONTENTS

CHAPTER TITLE PAGE

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENTS iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES x

LIST OF FIGURES xi

LIST OF SYMBOLS xiv

LIST OF APPENDICES xv

1 INTRODUCTION

1.1 Background Of Study 1

1.2 Problem Statement 2

1.3 Objectives Of Study 3

1.4 Scope of Study 3

1.5 Significance of Study 3

2 LITERATURE REVIEW

2.1 Introduction 5

2.2 Development of The Soil Nailing Method 6

2.3 Soil Nailed System 6

viii

2.4 Principal Theory Of Soil Nailing 8

2.5 Areas of Application 9

2.6 Nailing Failure Modes 10

2.6.1 Pullout Failure 10

2.6.2 Nail Tendon Failure 11

2.6.3 Face Failure 12

2.6.4 Overall Failure 14

2.7 Method Of Stability Analysis 15

2.7.1 Limit Equilibrium Method 16

2.8 Bishop And Morgenstern Slope Stability Chart 18

2.9 Various Types of Soil Nailing 23

2.10 Basic Element of Soil Nailed System 24

2.11 Limitations of Soil Nail 27

2.12 Construction Sequence of Soil Nailing 28

2.13 Advantages of Soil Nailing 31

2.14 Case History 33

2.14.1 Stabilization of Slope of Reservoir 33

2.14.2 Failure of Five Berms Soil Nailed Slope

and Seven Berms Cut Slope

36

2.15 Summary of Literature Review 39

3 METHODOLOGY

3.1 Introduction 40

3.2 Slope/W Software 42

3.3 Parameter Used in Modeling to Determine The

Effect of Shear Strength and Groundwater

Table

43

3.4 Parameter Used in Modeling to Determine The

Inclination of Soil Nail on Slope Stability

44

3.5 Case Study 45

3.5.1 Site Information 45

3.5.2 Slope Failure 47

3.5.3 Soil Properties of the Slope Failure 49

ix

3.5.4 Effect of Soil Nail on the Slope Stability

Analysis

49

4 RESULTS AND ANALYSIS

4.1 Introduction 51

4.2 Effect Of Shear Strength Parameters 52

4.2.1 Factor of Safety versus Various Slope Angle

for Various Internal Friction Angle

52

4.2.2 Factor of Safety versus Cohesion for

Various Internal Friction Angle

54

4.2.3 Factor of Safety versus Groundwater Level

for Various Internal Friction Angle

56

4.3 Determination on Optimum Soil Nail

Inclination On The Slope Stability

58

4.4 Slope Stability Analysis for Case Study 59

4.4.1 Without Soil Nail 59

4.4.2 With Soil Nail 60

5 CONCLUSION & DISCUSSION

5.1 Introduction 62

5.2 Suggestion and Discussion 63

5.3 Conclusion 63

REFERENCES 65

x

LIST OF TABLES

TABLE NO. TITLE PAGE

2.0 Values Of The Parameters Used In The Analysis 33

2.1 Variation Of Factor Of Safety With Cohesion Of The

Casing Material

34

2.2 Strength Parameters Of The Soil Samples 36

3.1 Modeling Details For Model A 42

3.2 Modeling Details For Model B 42

3.3 Modeling Details For Model C 43

3.4 The Soil Properties And Parameter For

Determination Of The Effects Of Soil Inclination On

The Slope Stability

44

3.5 The Adopted Design Parameters For Slope Stability

Analysis

48

4.1 Details Of The Models Used In The Analysis 52

4.2 Factor Of Safety For Model A 52

4.3 Factor Of Safety For Model B 54

4.4 Factor Of Safety For Model C 56

4.5 Factor Of Safety Of Nail Inclination For Slope Angle

45˚

58

4.6 Factor Of Safety Of Nail Inclination For Slope Angle

60˚

58

4.7 Results Of The Slope Stability For Case Study 60

xi

LIST OF FIGURES

FIGURE NO. TITLE PAGE

2.1 Active And Passive 8

2.2 Two-Zone Model Of Soil Nail System 9

2.3 Pullout Failure Mode 11

2.4 Nail Tendon Failure Mode 12

2.5 Face Failure Mode 13

2.6 Proper And Improper Detailings 14

2.7 Nail Load Diagram 15

2.8 The Definition Of The Factor Of Safety (FOS) 18

2.9 Bishop And Morgenstern Stability Charts (Bishop

And Morgenstern, 1960)

20

2.10 Typical Cross-Section Of A Soil Nail Wall 25

2.11 Typical Soil Nailing Construction Sequence 30

2.12 Typical Drawing Showing Construction Sequence 30

2.13 Slope Failure 33

2.14 Analysis Results 34

2.15 Slope Failure (Liew & Liong, G&P) 35

2.16 Slope Stability Analysis Results For Local Stability 37

2.17 Slope Stability Analysis Results For Global Stability 37

3.1 Flow Chart Of Research Methodology 40

3.2 A photo of Topographical Map of Slope Failure at

Taman Chantek, Pulau Pinang

45

3.3 An Overview Of The Survey Plan Of Slope Failure

Location At Taman Chantek, Pulau Pinang

46

xii

3.4 A Photo Of Slope Failure Which Covered With

Canvas

47

3.5 Another Failure Above Gabion Wall

47

3.6 Flow Chart To Determine An Optimum Nail

Inclination And FOS Value For Soil Nail Slope

49

4.1 Factor Of Safety Versus Various Slope Angle For

Various Internal Friction Angles

53

4.2 Factor Of Safety Versus Various Cohesion 55

4.3 Factor Of Safety Versus Various Internal Friction

Angle

55

4.4 Factor Of Safety Versus Groundwater Level 57

4.5 The Result Of Slope Stability Analysis For The

Existing Slope Without Soil Nail

59

4.6 Slope Stability Analysis For Case Study After

Application of Soil Nail

61

xiv

LIST OF SYMBOLS

Ø - Nail inclination

Ф - Angle of internal friction

ß - Slope Angle

c - Cohesion

FOS - Factor of safety

γ - Unit weight

τf - Shear strength

τ - Shear stress

m, n - Stability coefficient

-

xv

LIST OF APPENDICES

APPENDIX TITLE PAGE

A1 Slope Stability Analysis For Cut Slope Of 45

Degree With Nail Inclination Of 20 Degree

68



68



69



69



70

B1 Slope Stability Analysis For Cut Slope Of 60


72

B2 Slope Stability Analysis for Cut Slope of 60

Degree With Nail Inclination of 25 Degree

72



73



73



74

C1 Slope Stability Analysis For Case Study With

Nail Inclination Of 20 Degree

76

C2 Slope Stability Analysis for Case Study With

Nail Inclination of 25 Degree

76

C3 Slope Stability Analysis For Case Study With 77

xvi




77



78

C6 Slope Stability Analysis for Case Study With

Nail Inclination of 45 Degree

78



79

CHAPTER 1

INTRODUCTION

1.1 Background Of Study

Slope stability issue becomes one of the main problems in construction

industry due to nature of the topography and the weather conditions in Malaysia.

Slope failure has been acknowledged as one of the most frequent natural disaster that

can lead to great loss in property and life.

In Malaysia, the collapse of Block 1 of Highland Towers in 1993, slope

failure at Taman Hillview in November 2002 and the tragic landslide at Bukit Lanjan

in 2003 had prompted our government and public to concern about the stability of

slope and the risk involve in such circumstance. The most recent tragedy of slope

failure in Bukit Antarabangsa, Kuala Lumpur which killed 5 people is one of the

disasters that caused by slope failure. Since then, numerous landslide incidents had

occurred and the latest one was at Hulu Langat which 16 people had been killed.

These occurrences were related to the importance of the slope stability

technique. There are many methods of slope stability such as soil anchor, subsurface

2

drainage, shear piles and stone columns. The selection of the method to be applied

should base on many factors that related to the types of slopes and the soil properties.

This study is focusing on the soil nailing as the one of the methods in for stabilizing

slopes. This method has been used widely in many countries especially in Malaysia.

Hence, the analysis of slope stability is very important in order to protect the

slopes from fail and minimize the likelihood of slope failure. There are several

techniques to analyze slope stability in order to prevent slope stability, for example,

using method of slices. The method of slices is one of a technique that has been

widely used to analyze the slope stability in two dimensions. The sliding mass above

the failure surface is separated into a number of slices. The forces acting on each

slice are obtained by considering the mechanical equilibrium for the slices.

1.2 Problem Statement

Soil nailing is commonly used in Malaysian slopes either as a stabilization

measure for distressed slopes or for a very steep cut slopes. The selection of soil

nailing is due to its technical suitability as an effective slope stabilization method,

easy in construction and it is relatively maintenance free. As a result, many slope in

Malaysia that up to 25m in height is being used by using soil nailing as slope

stabilization. Therefore, a proper and systematic design procedures based on sound

fundamentals and confirmed by extensive research is necessary, in order to ensure

the soil nail slope performs satisfactory and to prevent repetition of tragedy highland

tower. For ensuring the problem can be overcome, software “Slope/W” was used to

study the effect of soil nailing for improvement and reinforcement of stability of the

slope.

3

1.3 Objectives of Study

The objectives of this study are:

i. To determine the effect of shear strength parameters and groundwater

table on slope stability

ii. To determine the optimum angle of nail inclination and slope degree with

higher FOS and the effect of soil nailing on slope stability.

iii. To verify effectiveness of soil nailing for soil slope in case study

1.4 Scope of Study

The study is limited to the problems involving:

i. To determine the most appropriate slope inclination angle of the soil

nailing on slope stability.

ii. To study the effect of shear strength parameters and groundwater level

on the slope stability.

iii. Various slope inclinations; Ø, cohesion; c, internal angle of friction; ф ,

and groundwater table were applied in the parametric study.

iv. All the analysis and result were obtained by using Slope/W 2007.

1.5 Significance of Study

The significances of the study are important to determine the effect of the

shear strength parameters in the slope stability. By doing this study, the efficiency of

4

soil nailing system can be proved to improve the slope stability. It also can help the

designer to determine the optimum of the nail inclination for improving the stability

of slope.

65

REFERENCE

Abramson, Lee, Thomas S.Lee & Sunil Glenn M (2002), Slope stability and

stabilisation methods

Barley. A.D. (1992), Soil Nailing Case Histories and Developments, Conferences

Retaining Structure Cambridge July 1992

Chen, C.S (2004), Failure of a Soil Nailed Slope. 15th Southeast Asian Geotechnical

Society Conference, 22 to 26 November 2004, Bangkok, Thailand

Chen, C.S. & Lim, C.S. (2005), Some Case Histories of Slope Remedial Works, 3rd

International Conference on Geotechnical Engineering

Cheng, Y.M., T.Lansivaara. W.B.Wei. (2006), Two-Dimensional Slope Stability

Analysis by Limit Equilibrium and Strength Reduction Methods, Journal of

Computers and Geotechnics, 34,137-150

Chow Chee-Meng & Tan Yean-Chin, Slope Stability using Soil Nails: Design

Assumption and Construction Realities, Gue & Partners Sdn. Bhd

Chow Chee-Meng & Tan Yean-Chin, Soil Nail Design: A Malaysian Perspective,

Gue & Partners Sdn. Bhd

Department of Transport.(1993), The Development of Specification for Soil Nailing,

Research report. 380

FHWA (1999), Demonstration Project 103: Design & Construction Monitoring of Soil

Nail Walls, Project Summary Report, Federal Highway Administration, US

Department of Transportation, Report No. FHWA A-IF-99-026

FHWA (2003), Geotechnical Engineering Circular No. 7 – Soil nail walls, Federal

Highway Administration, US Department of Transportation, Report No.

FHWA A0-IF-03-017

Geotechnical Engineering Office (2008), Guide to Soil Nail Design and Construction.

Geotechnical Engineering Office Civil Engineering and Development Department

The Government of the Hong Kong Special Administrative Region Hui Liu (2010),

Slope Remedial Work at Sri Plentong, Final Year Project Report, Faculty of

Civil Engineering Universiti Teknologi Malaysia

Liew, Shaw-Shong (2005), Soil Nailing for Slope Strengthening, Gue & Parneers

Sdn Bhd

66

Tain, S.N.L (2010), A Review of Soil Nailing Design Approaches. Journal of Civil

Engineering,1,1-6

Tan, Chia Chin. (2005), Appication of Soil Nailing as Protection and Reinforcement

for Slope Stabilization, Final Year Project Report, Faculty of Civil

Engineering Universiti Teknologi Malaysia

Thomas. C.S and Carlton L.H. (2003), Simplified Trial Wedge Method for Soil

Nailed Wall Analysis, Journal of geotechnical and Geoenvironmental

Engineering, 117-125

Yeung,Victor. (2008), Application of Soil Nailing for Slope Stability Purpose,

Degree of Bachelor of Engineering University of Technology Sydney.

Documents

ENHANCING STABILITY OF SLOPE USING SOIL NAILINGeprints.utm.my/id/eprint/79444/1/NorshazwinaJohariMFKA2016.pdf · dan paras air bawah tanah. Kemudian, pelbagai sudut kecerunan soil