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Section 2: Techniques in land surface evaluation |
1 Consultant Engineering Geologist, Milford, Guildford, Surrey, UK
2 School of Earth and Environmental Sciences, University of Greenwich, Kent, UK
3 Consultant Engineering Geologist, Winchester, Hampshire, UK
The condition of natural soils and rocks reflects the impact of a historical sequence of geological processes (Fookes 1997), including plate tectonics, depositional environment, structural and diagenetic change. Climate influences the effect of the atmosphere in producing surface-related weathering and, in particular, the climatic changes of the Quaternary have significantly modified the properties of near-surface soils and rocks. Such modifications continue under present-day environmental conditions.
Man-made or engineering structures are much younger compared to the geological time-scale but they also undergo change as a result of the effect of the natural environment in which they have been placed. The impact of these changes is governed by the materials that have been used in the construction, the way in which they have been incorporated in the design, and the quality of the workmanship. The materials are not always suitable for the environment in which they have been placed. An example is the use of pre-cast concrete with shallow reinforcement cover in a coastal environment where it is subject to seawater attack.
It follows, therefore, that engineering structures may be placed in a wide variety of environments in which chemical and physical attack will vary from harsh to benign. For each environment the factors which may influence the rate of attack can be developed into a rating system which will allow the assessment of the condition of the structure and its constituent materials. This provides a framework for:
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This 250-word extract was created in the absence of an abstract.
