Improvement Of Bearing Capacity Of Sandy Soil By Grouting

INTRODUCTION
1.1 BACKGROUND OF THE STUDY
The construction of structures on weak ground often requires the soil to be improved in order to ensure the safety and the stability of surrounding buildings. Soil is one of the most important engineering materials. Determination of soil conditions is the most important first phase of work for every type of civil engineering facility. The knowledge of soil is necessary for the designing of foundation, pavement, underground structures, embankments, earth retaining structures, dams etc. As a result, various parameters like bearing capacity, stress distribution in the soil beneath the loading area, the probable settlement of the foundation, effect of ground water and effect of vibrations etc are needed for the design of foundation. The thickness of pavement and its component parts depends upon the characteristics of the subsoil, which should be determined before design is made. The index properties such as density, plasticity characteristics and specific gravity, particle size distribution and gradation of the soil, permeability, consolidation and compaction characteristics and shear strength parameters under various drainage conditions needs to be determined for the construction of earth dams. In this region with a wide range of soil and hence the property of soil varies within short distances. A majority of the land area were being used for cultivation of crops. Soil in the residential area is not preloaded. The variation in the type of the soil through is not very marked. The performance of the soil in the designs cited above depends upon the characteristics of the soil. Hence, the testing of soil with relation to the determination of its physical properties and the evaluation of effects of certain other factors such as seepage conditions etc forms the most essential part of the development of soil engineering. The knowledge of theoretical soil mechanics, assuming the soil to be an ideal elastic isotropic and homogeneous material helps in predicting the behavior of the soil in the field. Ground improvement in granular soils can be achieved by different methods such as vibro-flotation, compaction piles, compaction with explosives, excavation and replacement, well point system, reinforced earth, grouting etc. The selection of the most suitable method depends on a variety of factors, such as: soil conditions, required degree of the compaction, type of structures to be supported, maximum depth of compaction, as well as site-specific considerations such as sensitivity of adjacent structures or installations, available time for completion of the project, competence of the contractor, availability of equipments and materials etc. Soil compaction can offer effective solutions for many foundation problems, and is especially useful for reducing total settlements in sands. However, efficient use of soil compaction methods requires that the geotechnical engineer understands all factors that influence the compaction process. The poor quality soils, especially their low bearing capacity, make it necessary to improve their properties by stabilization. The compaction of soils is intrinsically dependent upon the vertical effective stress, the type and gradation of soil, etc.

1.2 AIM AND OBJECTIVE
The main aim of this study is to discuss grouting as one of the possible solutions to the foundation problems by improving the properties of soil at shallow depths by using sodium silicate. The objectives are:
i. To determine the nature of the sandy soil particles.
ii. To determine the degree of the sandy soil compatibility.
iii. To carry out the improvement of sandy soil through grouting.
iv. Improving bearing capacity and shear strength of soil.
v. Compacting and confining the soil.
vi. Replacing the poor soil.
vii. Stabilizing the soil with chemicals (sodium silicate).
viii. Reducing the settlement of soil.

1.3 SCOPE OF THE STUDY
This research is focused on the quality and improvement of bearing capacity of sandy soil by grouting.

1.4 LIMITATIONS OF THE STUDY
The limitations of this study are:
TIME FACTOR: Limited time that does not permit to carryout many practical.
AREA OF STUDY: This project is limited the technical study of sandy soil properties.
METHOD USED: The existing standard laboratory methods for the determination of consistency limits, though in general use, still are not highly rational. They have various limitations and by which variations in test results are quite possible in the case of different trials. Fully rational methods have yet to be developed to define these limits especially in the case of liquid limit and plastic limit.

1.5 PROJECT ORGANISATION
The work is organized as follows: chapter one discuses the introductory part of the work, chapter two presents the literature review of the study, chapter three describes the methods applied, chapter four discusses the results of the work, chapter five summarizes the research outcomes and the recommendations.