UNIVERSITI TEKNOLOGI MARA

MECHANICS OF SINKHOLE DUE TO GROUND TREMOR

MOHD FIRDAUS BIN MOHD AKHBAR

Thesis submitted in fulfillment of the requirements for the degree of

Master of Science

Faculty of Civil Engineering

November 2014-

AUTHOR’S DECLARATION

I declare that thc work in this thesis was can'ied out in accordance with the regulations of

Universiti Teknologi MARA. It is original and is the results of my own work, unless

otherwise indicated or acknowledged as referenced work. This thesis has not been

submitted to any other academic institution or non-academic institution for any degree or

qualification.

I, hereby, acknowledge that I have been supplied with the Academic Rules and

Regulations for Post Graduate. Universiti Teknologi MARA, regulating the conduct of

my study and research.

Name of Student : Mohd Firdaus Bin Mohd Akhbar

Student ID. No. : 2009967143

Programme : Master of Science (Geotechnical

Engineering)

Faculty : Civil Engineering

Thesis Title 2 Mechanics of sinkhole Due To Ground

Tremor

Signature of Student : ..... W ....................... Date : November 2014

ABSTRACT

The abundance of limestone formation outcrops mostly in west peninsular Malaysia such as Perak is vulnerable to the geological hazards such as sinkhole. The primary reason for the sinkhole incidences are due to the uneven and dissolution of limestone formation. A sinkhole is a phenomenon where a natural depression or hole in the earth's surface occurred due to several reasons. Before sinkhole incidences happen, there is an initial condition in the ground, which is underlain by soluble bedrock such as limestone formation and topped off by its residual soil. When the effective stress from the overlying residual soil increase, the cavity roof on the limestone formation may not be able to support and the residual soil may sink into the existing cavity. A study was can-led out at the sinkhole prone area in Perak and Selangor. The physical characteristic of the limestone residual soil that vulnerable to sinkhole incidence that occupied these two sites was determined. The site investigation report consisted of Mackintosh Probe and Bomholes data from these two sites was analyzed in order to detemline the characteristic of the limestone residual soil that vulnerable to sinkhole incidence. Result showed that the limestone residual soil above cavity is normally constituted of loose silty SAND and soft sandy SILT. The application of the non-intrusive method can be useful to detect the abnormalities and type of material in the ground based on the geoelectrical resistivity index. A non-intrusive method using geoelectrical resistivity survey was applied to determine the geoelectrical resistivity index of the limestone residual soil at these two sites. The finding from this method was used to determine the relationship of the geoelectrical resistivity index with the physical and engineering properties of the limestone residual soil. The earthquake event can pose a hazard known as ground tremor. The sinkhole incidence may also formed in response to dynamic loading from earthquake tremor. The energy fmm an earthquake tremor released a force which is a shear stress. The vibration fmm the ground tremor will start to accumulate the shear strain that occurred between {he soils particles. Because of that, sinkhole incidences triggered as a

result of gravity forces pulling the soil particles down when the soil particles experienced slippage or reorientation. This is happened when there is a significant of reduction in the shear modulus of the soil that caused the soil loose it strength below the amount needed for static stability. In order to simulate the sinkhole incidence during the ground tremor, the laboratory sinkhole model was setup using a glass tank with the remoulded limestone residual soil that was collected at Perak site. The laboratory sinkhole model was tested under vibration test using shaking table. The objective of the laboratory sinkhole model is to investigate the behavior and effects of percentage of fines material and presence of moisture content to the shear modulus of the remoulded limestone residual soil when subjected to ground tremor. The finding from the laboratory sinkhole model showed that the shear modulus of all remoulded limestone residual soil samples had significant reduction during the vibration and sinkhole incidences were governed by the effects of different percentage of fines material and with the presence of moisture content.

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TABLE OF CONTENTS

AUTHOR’S DECLARATION

ABSTRACT

ACKNOWLEDGEMENT

TABLE OF CONTENTS

LIST OF TABLES

LIST OF FIGURES

LIST OF SYMBOLS

CHAPTER ONE: INTRODUCTION

1.1 Background of Research

1.2 Problem Statement

1.3 Objective of Research

1.4 Significance of Research

1.5 Scope and Limitalion

1.6 Thesis Outline

CHAPTER TWO: LITERATURE REVIEW

2.! Nature of Sinkholes Formation

2.2 Bedrock Formation Beneath Sinkhole

2.3 Triggering Factor to Sinkholes Formation

2.4 Sinkholes Incidences in Malaysia

2.5 Geoelectrical Resistivity Survey

2.6 Earthquake Induced sinkhole Incidenoes

2.7 Relationship of Shear Modulus to sinkhole Formation

2.8 Laboratory Studies on Soil Failure due to Vibration

2.9 Gap of Knowledge

Page

XV

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CHAPTER THREE: RESEARCH METHODOLOGY 43

3.1 Introduction 43

3.2 Desk Study 44

3.3 Field Work 45

3.4 Laboratory Work 53

3.5 Physical Model Study 58

CHAPTER FOUR: RESULT AND DISCUSSION 65

4.l Introduction 65

4.2 Site Geology 65

4.3 Subsurface Investigation Report 69

4.4 Geoeleclrical Resis‘ivity Inisitu Result 81

4.5 Campurison of Physical Properties nf Ilimcslonc Residual Soil 124

4.6 Mechanical Properties ofLimcslonc Residual Soil 130

4.7 sinkhole Model Subjected to Vibration Test 144

CHAPTER FIVE: CONCLUSION AND RECOMMENDATIONS 158

5.1 The Characteristic of Limestone Residual Soil That Vulnerable

m sinkhole Incidence 158

5.2 The Rclmionahip 0f (jeoeleclricul Rcsislivily Index, Physical and Engineering

Propcnics of Limestone Rcsidua] Snil 160

5.3 The Effect of I’crcemuge of Fines lo Changes in Shear Modulus and Sinkhole

Formation Suhjcclcd 10 Ground Tremor 161

54 Recommendations 162

REFERENCES 164

APPENDICES 172

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