ABSTRACT

The permeability coefficient of sandy and lateritic soil was carried out. In this work, falling head permeability test, sieve analysis, moisture content and Atterberg limit tests were performed on the soil samples collected from 5 different communities in Khana L.G.A of Rivers State. Experimental permeability coefficients of the soil was determined using falling head permeability test. The result of the falling head permeability test revealed that the permeability coefficient of laterite soil in Khana ranges from 0.005 – 0.073cm/s and that of sandy soil ranges from 0.113 – 0.929cm/s. The for laterite and sand is approximately 0.12mm.

CHAPTER ONE INTRODUCTION 1.1 BACKGROUND OF STUDY

A certain number of problems relating to the interacting factor of soils had been the major concern of geotechnical engineers over the years. This is because the engineering properties of soils exhibits varying and uncertain behaviors, due to the complex and imprecise physical process associated with the formation of these materials which is a matter of concern for geotechnical engineers. Amongst the many interacting factors of the soil that the engineer has to deal with, permeability is one of its very important engineering properties (Whiteman, 1969) This reason is attributed to the fact that it plays a predominant role in solving of a good number of engineering problems such as settlement of buildings, yield of wells, seepage through and below the earth structures; it also controls the hydraulic stability of soil masses. It is important to note the permeability of soils is influenced by various factors such as particle size, structure of soils, shape of particles, void ratio, properties of water and degree of saturation (Handsbo, 1994). Furthermore, it is needful to mention that several methods can be adopted in the determination of the coefficient of permeability in the field and laboratory generally depending on the site conditions and type of soil. Other research works have been carried out to relate permeability and compaction characteristics of soils to their physical properties: Rowan and Graham (1948) used gradation, specific gravity, and shrinkage limit in their correlation equations, Davidson and Gardiner (1949) eliminated the specific gravity from the equations of Rowan and Graham (1948), but included a plasticity index.Taylor (1948) formulated a theoretical equation, based on the capillary tube model, for flow through porous media, relating the permeability with a representative grain size etc. The physical properties used generally include plasticity characteristics (liquid limit, plastic limit, shrinkage limit, and plasticity index), specific gravity, and grain size distribution that are attainable from relatively straightforward laboratory tests. However, specific index properties used in various correlation equations differ considerably. To ascertain the permeability coefficient of the soil, soil samples are to be collected and taken to the laboratory to carry out the above mention practical. For the purpose of this work, various soil samples have been collected from various locations within the study area to determine the permeability coefficient of the study area.

1.2 STATEMENT OF PROBLEM

Soil permeability is a key test for the determination of infiltration capacity of any soil. It aids the engineers to effectively control flooding in an area. Permeability coefficient also aids soil classification, dam design, filter construction, slope stability analysis and drainage design. This work is aimed at determining the permeability coefficient of sandy and lateritic soil in Khana Local Government area.

1.3 OBJECTIVES OF STUDY

The aim of this study is to determine the permeability coefficient of sandy and lateritic soil in Khana Local Government Area. The specific objectives of the study are: i. Determine the permeability coefficient of sandy and lateritic soil in Khana ii. To determine the coefficient of uniformity (Cu) for sandy and lateritic soil in Khana iii. To determine the Plastic and the Liquid limit values for Khana soil

1.4 SCOPE OF STUDY

For this project to be effectively worked out, certain areas will be covered to ensure that the research is comprehensive and all-encompassing in the subject matter. It include: i. Reconnaisance visit the study area ii. Sample collection iii. Carry out the moisture content test iv. Carry out permeability test v. Perform sieve analysis vi. Perform atterberg limit test

1.5 AREA OF STUDY

This work is centered on Khana Local Government Area, with coordinates – 4˚42ˈN 7˚21ˈE. Created in 1992, Its administrative seat is the town of Bori, with an area of 220 sqm (560 km2) (khana, Rivers – Wikipedia). It has a population of 294,217 (census 2006).

1.6 LIMITATION OF STUDY

In the course of collecting soil samples from different locations, some challenges were encountered: I. We were restricted from collecting soil samples because of communal beliefs, stating that their ancestral soil cannot be given out to strangers for whatever reason. II. Due to the current crises in Ogoni land, most of the anticipated communities were badly affected, and it resulted to a serious setback in the process of collecting soil samples. III. In other locations, before we were allowed to collect soil samples, we had to go through protocols, meeting with various leaders of the community, from the youth leaders, to the community development council (CDC) chairman, to their paramount ruler. Moving in this succession stalled the progress of this work for some time.