This work introduces the coastal geo-engineering issues for a suitable selection and geomaterial characterisation of quarries. The development of the research had two main phases:
the field survey, applied cartography and inspection of maritime structures and
the geological and geotechnical quarry assessment. This study reports results from the second phase which comprises the evaluation of quarries and the identification of potential areas for the extraction of armourstone with quality and availability to supply maritime structures. It was proposed a zoning of the NW Portugal region and taken into account some features like the land use, urban and settlement plans, geological setting, geotechnical and geomechanical description/typification of the rock masses. 459 quarries were identified, georeferenced and distributed in a total area of 14.010km2. More than 200 sites were selected, characterised and included in the GIS database project with interactive support (e.g. hyperlinks for the datasheets, photos or essential information). A total area of 4,1% was calculated, including relevant geological conditions and comprising existent quarries (active/inactive) or new places (suitable or predictable areas). A multidisciplinary perspective must be adopted providing a cost-effective method useful to the incorporation of important concepts (durability and integrity) in geo-monitoring coastal plans and highlighting GIS coastal projects.
Presently, concepts in geotechnical and geo-engineering fields are important for rock characterisation and subject of interest by many researchers ([1]). For the design and/or maintenance of coastal defence works the application of analysis methods and technologies related with these domains, are essential (e.g., [2]; [3]; [4]). From the geoengineering point of view, and within a scientific context, impacts caused by the construction of large structures and incorrect land use along the coastal areas, require comprehensive geological, geomechanical studies and engineering solutions for their mitigation. The coastal zone is considered highly dynamic and spatially variable ([5]) and therefore, coastal protection structures are important features in this kind of environment to take into account during a successful coastal maintenance program or management strategy. During the coastal structure's life it is necessary maintenance and repair works, hence, natural and durable rock is one of the main geomaterials employed in maritime works. The definition of geomaterial is: "processed or unprocessed soils, rocks or minerals used in the construction of buildings or structures, including man-made construction materials manufactured from soils, rocks or minerals" ([6]; [7]). This category of rock materials used in coastal defence works are subject to environmental conditions which differ, both in severity and type, from those encountered in other situations. Design requirements also include elements specific to coastal engineering structures and both these aspects must be given due consideration in the selection and specification of the rock. The two most important groups of properties of rock for use in coastal engineering are the geometric properties of shape, size and grading and the physical properties which include density and factors relating to mechanical strength, resistance to abrasion, porosity and durability ([7]).
