Mehmet Yalçın Koca

The relationships between the rock material properties and weathering grades of andesitic rocks around İzmir, Turkey

Abstractİzmir is the third largest city in Western Turkey founded on sedimentary and volcanic rocks. Pyroxene andesitic rocks with the age of Late Miocene are found as andesitic lavas, autobreccias, basaltic andesites, and andesitic agglomerates in and nearby the city centre of İzmir. There are a number of major engineering structures under construction in andesitic rocks involving large slope cuts, tunnels and shafts in the city. Thus, the short-term and long-term engineering behaviours of these rocks are very important in terms of the excavation and the stability of these structures. For these reasons, rock material properties of andesitic rocks were investigated in this study. The relationships between the rock material and weathering grades of the volcanic rocks were determined. Initially, the weathering grades of andesitic rocks were established on core samples recovered from boreholes drilled for site investigations of the İzmir subway route and the abandoned andesite quarries in the region. The samples were also subject to petrographic modal analysis, chemical analysis, and laboratory tests to determine the physical and mechanical properties of andesitic rocks. The relationships between the index and engineering properties for different weathering grades of andesitic rocks are also established for engineering use in practice. In addition, a new weathering index, based on major element analyses, was proposed to be used for the determination of weathering grade of andesitic rock.

Large-scale land-suitability mapping in the GIS environment for the construction site of the University Olympic Village in Izmir (Turkey)

Large-scale land-suitability mapping in the GIS environment for the construction site of the University Olympic Village in Izmir (Turkey) Participants of the 23rd University Olympic Games held in Izmir (Turkey) were hosted in a Universiade Olympic Village that had to be newly constructed. A risk analysis has been performed to assess potential engineering problems at the envisaged construction site. The risk analysis was largely based on a new, large-scale land-suitability map that was prepared in the GIS environment with much detail for this type of construction work. Information was collected from several maps, in combination with mapping in the field, drilling and seismic data. Geological, geotechnical, geophysical and morphological data were then superimposed on these analyses. This sequence of overlay analyses was performed with the help of GIS software (MapInfo Professional 7.5); this resulted in five hazard maps. Risk points (1-11) were then attributed to the different zones in the five digital hazard maps. A land-suitability map indicating the suitability for envisaged constructional activities was subsequently obtained in the form of an overlay of the five hazard maps, thus allowing to calculate a total risk for each zone on this map. The land-suitability map that was thus obtained, has been prepared for a 1:1,000 scale development plan; such a large scale is uncommon in this context.

Ground Control for Underground Evaporite Mine in Turkey

Controlling the potential for hazardous ground movements and inundation of an underground mine to within acceptable limits is essential. Both hazards can result in serious harm or death of workers or persons that may inadvertently enter a mining area. The hazards are not always obvious. For example, the outcome of the hazard of a loose rock falling from a sidewall and striking someone can be fatal by either direct physical contact, or damaging the plant in which the worker is working. The presence of certain geological structure (natural planes of weakness in the rock) that override the effectiveness of any ground control measure, is not always obvious from within the mine.