The Geotechnical Properties of Soils along Appleton/Zoo Road

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