Geotechnical Hazard Assessment
Abstract
Abstract The development of geothermal power projects in some of the more remote regions of South East Asia has presented a variety of interesting geotechnical challenges. By definition the location of steamfields and associated power generating stations are in tectonically active regions with, at least in geological terms, a rapidly changing environment. Land mass stability can have a significant impact on the successful development of a steamfield or the siting of a power plant.
The purpose of this paper is to describe a methodology which has been used in the geotechnical hazard assessment of a geothermal environment. Since the method has been developed from simple, readily identifiable geological, geomorphological and geotechnical features it is proposed that the system could be modified and adopted for the planning and execution of any major infrastructure project.
The most valued output from a hazard assessment is a Hazard Map which can be used by planners and project managers to at least qualitatively recognise areas which could pose a significant geotechnical hazard during project development. In order to prepare a Hazard Map it is first necessary to identify and quantify the relative effects of a large number of site specific and regional variables, for example seismicity, slope angle, drainage, geology or cultivation and landuse.
The proposed methodology identifies three generic hazard attributes called Regional, State of Nature, Mass Movement. Each of these attributes is subdivided into individual hazard factors which are assigned a qualitative rating and weighting coefficient based on an assessment of its potential to contribute to ground failure. The Hazard Map is the result of the cumulative rating for each individual land unit (grid or slope facet).