Geology Reference
In-Depth Information
engineering geologist. The bias here is towards UK practice.
2.1 FOUNDATIONS
2.1.1 BS 8004:1986 Code of practice for foundations
As with BS5930, this code of practice (BSI, 1986) gives general guidance and background information that is
very useful in guiding the geotechnical engineer and engineering geologist. The code provides recommendations
for the design and construction of foundations for buildings and engineering structures. It introduces general
principles of design, as well as detailed consideration of the design and installation of the foundations. The code
also discusses site operations and construction processes in foundation engineering, and the durability of the
various materials used in foundation structures. Section 11 deals with safety issues.
In the UK, BS 8004 is superseded by BSI (2004), which adopts a limit state approach to design rather than a
lumped safety factor approach, as discussed later.
2.1.2 Other codes and standards
Whereas BS 8004 has been superseded in the UK, similar codes are still used internationally. For example, CP4:
2003, the Code of Practice for Foundations in Singapore (Singapore Standards, 2003), provides general
guidance on foundation design, specific to local ground conditions. In Hong Kong, comprehensive guidance is
given in GEO Publication No. 1/2006 (Foundation Design and Construction).
2.2 EARTHWORKS AND RETAINING STRUCTURES
2.2.1 BS 6031:1981 Code of practice for earthworks
BSI (1981a) gives advice on formation of earthworks for civil engineering projects such as highways, railways
and air
elds, and on bulk excavations for foundations, pipelines and drainage works. It gives some UK-focused
advice on design and construction of cuttings and embankments. Advice is also given on methods of excavating
trenches, pits and temporary support to the sides, including timbering, sheet piling, diaphragm walls and
contiguous bored piled walls.
2.2.2 BS 8002:1994 Code of practice for earth retaining structures
BSI (1994) is aimed at UK practitioners and provides guidance on the design and construction of retaining
structures up to about 15m high.
More detailed guidance on retaining wall design, especially where dealing with weathered rocks, is given in GEO
(1993) Geoguide 1: Guide for Retaining Wall Design, which, like many other Hong Kong guides and
publications, is downloadable from the Hong Kong Government Civil Engineering Design and Development
website (
www.cedd.gov.hk).
2.3 EUROCODE 7: GEOTECHNICAL DESIGN
The Eurocodes comprise a suite of ten standards, now adopted as British Standards, which have
replaced the majority of older national codes of practice as the basis for designing buildings and civil engineering
structures in the UK and in most member states of the European Community. As commented above, the
superseded codes of practice still contain very useful guidance on good practice, albeit that there has been a
fundamental shift in design concept from a lumped Factor of Safety (FoS) to a partial factors approach.
Fundamentally, the concepts used in the earlier codes of practice and the Eurocodes are the same: under extreme
loading conditions, structures must not fail catastrophically and in day-to-day service, structures should not
suffer deformations that would a) render the structure incapable of achieving the use for which it was designed
or b) suffer deformations that take the structure beyond its aesthetic appearance requirements; these are
different examples of limit states.
Ultimate limit state failure might include the collapse of a slope, bearing capacity failure of a building, or blocks
of rock falling out of the roof of a tunnel, or might be identi
ed as piping failure through the foundations of a
dam. Serviceability limit state failure could be de
ned as excessive settlement, the classic example being the
Leaning Tower of Pisa, which has settled dramatically but not collapsed.
