ABSTRACT
This project was undertaken to determine the geotechnical properties of soils along Appleton/Zoo road. A total of nine (9) samples, both disturbed and undisturbed, were collected at chainages - 0+275, 0+325 and 0+525 respectively and each drilled to a depth of 1 m and at sampling depths of 0–0.3 m, 0.3–0.6m and 0.6–1.0 m respectively. These samples were subjected to the following laboratory tests: Particle (grain) size analysis comprising determination of percentage clay, silt and sand, Atterberg limit test comprising the liquid, plastic and shrinkage limits respectively, and Specific gravity. Other tests include Compaction test, and California Bearing Ratio (CBR) test; which were conducted to test likely failure due to the geotechnical properties along the road under investigation. Grain size analysis revealed that the percentages passing through the No.200 BS sieve are 88%, 87%, 89%, 56%, 59% and 59% respectively for P1 (P1L1, P1L2, P1L3), and P2 (P2L1, P2L2, P2L3). While P3 (P3L1, P3L2, P3L3) contained 24%, 28% and 23% respectively. The values of the liquid limit (LL) of all the samples are between 35% - 48% and plasticity index (PI) values are between 23% - 31%. The California bearing ratio (unsoaked) ranges between 20% and 55%. The specific gravity ranges between 2.62 - 2.68 while the maximum dry density ranges between 1.512Mg/m3 – 1.996Mg/m3 with their optimum moisture contents ranging between 11.3% - 23.9%. The results obtained were analyzed and compared with some standards and specifications (i.e. NSRB and BS 1377) which revealed that most of the soil samples are unsuitable for engineering construction or base materials due to the high content of expansive clay of high plasticity which swells on moisture influx and high compressibility, therefore are unsuitable materials for road construction. Recommendations were made to prevent future failure of the road and to ensure proper design and construction that will stand the test of time.
TABLE OF CONTENTS
Title Page i
Certification ii
Dedication iii
Acknowledgement iv
Abstract v
Table of Contents vi
List of Figures ix
List of Tables x
List of Plates xi
List of Charts xii
CHAPTER ONE: INTRODUCTION
1.1 General Background 1
1.2 Scope Of Study 2
1.3 Geology Of Study Area 2
1.4 Aims and Objectives 4
1.5 Justification of Study 4
CHAPTER TWO: LITERATURE REVIEW
2.1 Introduction 6
2.2 Some Problem soils in Nigeria 6
2.3 Soil Problems 9
2.4 Geotechnical Properties of Soils 10
2.4.1 Mechanical Analysis of Soil 11
2.4.2 Soil Consistency 14
2.4.3 Compaction 17
2.4.4 Specific gravity 18
2.4.5 California Bearing Ratio 19
2.5 Classification Systems of Soil 20
2.6 Other Research Works 23
2.7 Causes of Road Failure in Nigeria 25
2.8 Effects of Road Failures 29
2.9 Remedies and Recommendations to Road Failures 30
CHAPTER THREE: RESEARCH METHODOLOGY
3.1 Materials and Methods 34
3.1.1 Sampling 34
3.1.2 Test Procedures 35
CHAPTER FOUR: RESULTS AND DISCUSSION
4.1 Mechanical Analysis and Atterberg Limits 46
4.1.1 Mechanical Analysis 46
4.1.2 Atterberg Limits 46
CHAPTER FIVE: CONCLUSION AND RECOMMENDATIONS
5.1 Conclusion 63
5.2 Recommendations 63
REFERENCES
APPENDIX
LIST OF FIGURES
Figure Title Page
1a. The Study Area 3
1b. Geology of the University of Ibadan 4
2. The Geologic Formations of Some Problem soils 8
3. Hydrometer Test 14
4. Changes in Soil states 15
5. Existing Chainages of Unsuitable areas on Appleton Road 34
6. Casagrande Plasticity Chart 52
LIST OF TABLES
Table Title Page
1. Standard Sieves 12
2. Soil Classification Systems of Soil according to Plasticity Index 17
3. AASHTO Classification System 21
4. US Classification System 22
5. Summary of Geotechnical Properties of Nigerian soils for Road 24
Construction
6. Soil Profiles of the Study area 49
7. Physical Properties of Soil samples 50
8. Grain Size Distribution of the Studied Soil samples by Wet sieving 51
9. Summary of Results of Sieve Analysis of Soil samples 52
10. Results of Atterberg Limits and Specific Gravity of samples 53
11. Results of Compaction Tests (Standard Proctor test) 63
12. CBR Test Results for Undisturbed soil (In-situ soil samples) 73
LIST OF PLATES
Plate Title Page
1. Edge failure along a driveway 28
2. Pot holes along a driveway 28
3. Picture showing the soil strata at different points along the study area 33
4. A cross section of pictures showing the collection of soil samples from 22
the study area.
5. Particle Size Distribution Test by Wet sieving 37
6. Atterberg Limit Tests (Liquid and Plastic limits) 40
7. Compaction Test 42
8. California Bearing Ratio Test 44
LIST OF CHARTS
Chart Title Page
1. Compilation of Particle size distribution curves for the Nine samples 52
2. Atterberg graphs of soil samples 54
3. Compaction curves of the samples 64
