Site Investigation - Elements of Soil Mechanics - page 156

Chapter 6
Site Investigation
A site investigation is an essential part of the preliminary design work on any important geotechnical
structure. Its purpose is to obtain information about the proposed site that can be used by the engineer
to achieve a safe and economical design. Information retrieved during a site investigation can be very
diverse and can include information about the past history of the site and ground information such as the
sequences of strata and the depth of the groundwater level. During the ground investigation phase,
samples of soil and rock can be taken for identification and laboratory testing, and in situ testing may be
performed.
The primary objectives of a site investigation are listed in BS 5930: Code of practice for site investiga-
tions (BSI, 1999 ):
(i) to assess the general suitability of the site for the proposed works;
(ii) to enable an adequate and economic design to be prepared;
(iii) to foresee and provide against difficulties that may arise during construction due to ground and other
local conditions;
(iv) to predict any adverse effect of the proposed construction on neighbouring structures.
In addition a site investigation is often necessary to assess the safety of an existing structure or to inves-
tigate a case where failure has occurred.
6.1 EN 1997-2:2007 - Ground investigation and testing
As we saw in Chapter 5 , Part 2 of Eurocode 7 (EN 1997-2:2007) is the part that deals with ground inves-
tigation and testing. The contents of this document are shown in Fig. 5.3. Prior to the publication of EN
1997-2, site investigation practice in the UK followed the guidelines offered in BS 5930: Code of practice
for site investigations . Although BS 5930 remains in current use, the procedures of EN 1997-2, together
with the guidance provided in the many testing standards that are used in conjunction with it, are now in
force. Some of these relevant testing standards, published by CEN and cited throughout EN 1997-2, are
listed below:
EN ISO 14688 Geotechnical investigation and testing - Identification and classification of soil (2 parts)
EN ISO 14689 Geotechnical investigation and testing - Identification and classification of rock (1 part)
EN ISO 17892* Geotechnical investigation and testing - Laboratory testing of soil (12 parts)
EN ISO 22282 Geotechnical investigation and testing - Geohydraulic testing (6 parts)
EN ISO 22475 Geotechnical investigation and testing - Sampling and groundwater measurement (3 parts)
EN ISO 22476 Geotechnical investigation and testing - Field testing (13 parts)
EN ISO 22477 Geotechnical investigation and testing - Testing of geotechnical structures (1 part, to date)