Introduction - Geotechnical Engineering Investigation - page 3

heave, collapse, and subsidence. Although some elements of mathematical analysis for
evaluating foundation settlements, groundwater flow, slope stability, and earthquake
engineering are presented in this work, the main objective is to provide the basis for
understanding the physical phenomena involved as background for comprehending the
need for the various elements of investigation. This topic does not aim to provide a basis
for the analysis and design of slopes, retaining structures, closed excavations, foundations,
and ground improvement systems.

Predicting Geologic Conditions
For many practitioners, the basic elements of an investigation include a site visit followed
by test borings. If one has worked in the area before and is familiar with the conditions,
this approach may be adequate. If the study location is new to the practitioners, however,
they should apply the procedures that enable them to predict the significant characteris-
tics of the geologic conditions. Prediction for a given location is based on identifying the
local geology, interpreting the landform of the area, and applying a knowledge of the char-
acteristics of the various soil deposits and rock formations. At this point a comprehensive
subsurface investigation can be planned. It is an objective of this topic to assist the practi-
tioner in developing skills in predicting geologic conditions.

1.2 Scope

1.2.1 General

This topic is divided into three parts:

Part I: Investigation Methods and Procedures covers field exploration, field and
laboratory measurements of properties, and field instrumentation.

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Part II: Characteristics of Geologic Materials and Formations covers rock masses,
soil formations, and surface and subsurface water. The emphasis is on origin,
mode of occurrence, or deposition as related to their significance in terrain analy-
sis and the prediction of geologic conditions, including characteristic properties
and their impact on engineered construction.

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Part III: Geologic Hazards covers landslides and other forms of slope failure;
ground subsidence, collapse, and heave; and earthquakes (flooding and erosion
are covered in Part II under “Water”). The causes, effects, modes of occurrence,
and methods of investigation and treatment are described for each phenomenon.

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1.2.2 Investigation Methods and Procedures (Part I)

Exploration (Chapter 2 )
Test boring has long been the standard investigation procedure in many countries, but
there are various other tools and methods available that can be used to provide compre-
hensive information on geologic conditions.
Data collection and landform (or terrain) analysis are particularly important in cases where
large land areas are involved, or where the project area is unfamiliar to the investigator.