Environmental Engineering Reference
In-Depth Information
4.4.1
Broad regional studies
4.4.1.1
Objectives
1. To provide an understanding of the geological history of the project area, that is, of the
processes which have developed the present geological situation at and in a broad
region around the site. In particular it is important to determine the following:
- Major geological processes which have the potential to cause impact on the project;
- Any processes that are active or potentially active, e.g. as listed on
Table 4.2
;
- The possible effects of any active processes on the proposed works both during con-
struction and in service;
- Whether any construction activities (e.g. excavation) or operation of the storage are
likely to cause such changes to the existing regime (e.g. stress or hydrologic) as to
require remedial works or to affect the project feasibility.
2. To determine the regional stratigraphy and geological structure;
3. To explain the geomorphology of the project area in terms of the regional stratigraphy,
structure and geological history;
4. To draw attention to important features, e.g. major faults or landslides, occurring at or
close to the site, but not exposed or recognisable at the site;
5. To get an appreciation of the regional groundwater conditions;
6. To form a logical basis for the location and proving of sources of construction materials.
4.4.1.2
Activities
The amount and money spent on regional studies will depend upon the size and com-
plexity of the project, its consequence of failure, and the amount and relevance of regional
information already available. The activities usually will include some or all of the
following:
1. Examination of existing regional geological maps, cross sections and reports;
2. Interpretation of satellite images and aerial photographs;
3. Interpretation of ground photographs;
4. Ground reconnaissance over previously mapped areas, and remapping of important
areas with the project objectives in mind;
5. Compilation of regional plans and cross sections showing the proposed project works.
4.4.2
Studies at intermediate and detailed scales
4.4.2.1
Objectives
1. To explain the development of the site topography in terms of the regional and local
geology and geological history;
2. To delineate any major features, e.g. folds, faults or landslides, which may or may not
be indicated already by the regional studies;
3. To provide geotechnical models for the site and for particular project features, and to
provide answers to the geotechnical engineering questions.
4.4.2.2
Activities
1. Geotechnical mapping on intermediate and detailed scales;
2. Studies of the pattern of defects using structural geology and stereographic methods;
3. Application of geophysical methods (commonly seismic refraction) and interpretation
of the results in the light of the evolving geological picture;
4. Planning and technical supervision of direct exploration, which can include core (or
other) drilling, sluicing, and excavation of pits, trenches, shafts or tunnels;
