ancient times, Man has taken into serious consideration the soil
or ground that is to be used for the construction of various
works such as roads, bridges (Fig.
buildings, water dams (Fig.
ports and mines. Building
work was carried out as soon as it was decided what effect the
ground would have on the stability and safety of his structures.
This relationship between the ground and any structure
that is built on it constitutes the cornerstone on which the
foundation of any structure is based upon.
The scientific branch that studies this relationship is
Engineering Geology, and its ultimate objective is the study and
understanding of the mechanical behaviour of all geological
formations and the interaction of these formations to any type
of civil engineering structure.
Engineering Geology ensures the stability and safety of a
structure under static and dynamic conditions in the foundation
ground (soil and rock) is often a heterogeneous mass that may
change vertically or horizontally. These changes are often unpredictable due to a number of
reasons including the way and conditions in which it was formed,
the local geological conditions, the tectonic effects and the
seismic strain. Thus,
the knowledge of the characteristics of the material on which a
structure is to be constructed constitutes the basic presumption
for the stability of the structure.
The knowledge of the characteristics of the ground is achieved through a geotechnical investigation, which is divided into site and laboratory investigations. During the site investigation, knowledge is gained on matters such as the type, composition and structure of the geological formations, their thickness and side variations, the main mechanical properties of the ground and the hydrogeology of the area. These characteristics of the ground are obtained through geological mapping, geophysical surveys, exploratory boreholes, pits and trenches. The laboratory investigations include a number of tests (Fig. 3) and analyses on samples collected during the site investigation to obtain the physical and mechanical properties of the ground as well as its chemical and hydraulic characteristics.