THE COMPRESSIBILITY PROPERTIES OF SOIL

THE COMPRESSIBILITY PROPERTIES OF SOIL

CHAPTER ONE

INTRODUCTION

1.1 BACKGROUND OF THE STUDY

Maryland is located in Enugu South in Enugu State. The subsoil of this region consists of fine grained soils with a considerable part of soft soil deposit which extends to a considerable depth.

When a compressive load is applied to a soil mass, the volume of the soil mass tends to reduce, due to reduction in its voids. This reduction in volume of a soil mass on application of a compressive stress can rather be placed either normally (laterally), or vertically or in both directions depending on how the soil mass is allowed to deform. When a vertical compression deformation is non-uniform it poses serious danger to the safety of structures and other civil engineering facilities, therefore there is need to study the compressibility properties of soil in Maryland.

1.1.1 COMPRESSIBILITY

This is the degree to which a soil mass decreases in volume when supporting a load.  Compressibility is reduced in a situation where there are more coarse-grained soils in contact with each other. It increases as the proportion of small particles increases and becomes highest in fine-grained soils which contain organic matter.

Compressibility is approximately proportional to the plastic index. The greater the plastic index (PI), the greater the compressibility of the soil. (Adeyemi 2014).

1.1.2      PLASTICITY INDEX

This can be defined as the numerical difference between the liquid limit and plastic limit. The plasticity index is expressed in percentage of the dry weight of the soil sample and also it shows the size of range of the moisture contents at which the soil remains plastic.

The plasticity index also gives a good indication of compressibility. The greater the plastic limit the greater the soil compressibility (Ashworth 1966).

1.2  AIMS AND OBJECTIVES

       The aims and objectives of this project includes

i.   To study compressibility

ii.  To obtain the compressibility properties of soil in Maryland area.

iii. To obtain data that may be used in predicting the rate and the amount of settlement of structures in the area.

1.3  SCOPE OF STUDY

The scope of this project is limited to obtaining the compressibility properties of soil in Maryland area.

1.4  SIGNIFICANCE OF THE STUDY

    i.  This project will help to understand the compressibility properties of soil in Maryland area which will reduce the problems that geotechnical engineers face in designing economic foundation for the required infrastructure in Maryland area.

   ii.  The compressibility properties of the soil in the area obtained from labouratory test might be used to estimate the magnitude and the rate of settlement of a structure or an earth fill in Maryland area.

1.5 COMPRESSIBILITY PARAMETERS:

To obtain the compressibility properties of soil in Maryland, labouratory test will be carried out to obtain.

i.  Coefficient of compression/compression index (CC).

ii.  Swell index (CS)

iii.  Coefficient of compressibility (AV)

iv.  Coefficient of volume compressibility (MV)