Contemporarily, there are 16 coal-burning thermal power plants currently operating in Turkey. This number is expected to rise to 46 in the future. Annually, about 15 million tons of fly ash are removed from the existing thermal power plants in Turkey, but a small proportion of it, 2%, is recyclable. Turkey’s plants are fired by lignite, producing Class C fly ash containing a high percentage of lime. Sulfate and alkali levels are also higher in Class C fly ashes. Therefore, fly ash is, commonly, unsuitable as an additive in cement or concrete in Turkey. In this study, highly alkaline fly ash obtained from the Yeniköy thermal power plants is combined with soil samples in different proportions (5%, 10%, 15%, 20%, and 25%) and changes in the geomechanical properties of Ankara clay were investigated. The effect of curing time on the physicomechanical properties of the fly ash mixed soil samples was also analyzed. The soil classification of Ankara clay changed from CH to MH due to fly ash additives. Free swelling index values showed a decrease of 92.6%. Direct shear tests on the cohesion value of Ankara clay have shown increases by multiples of 15.85 and 3.01 in internal friction angle values. The California bearing ratio has seen a more drastic increase in value (68.7 times for 25% fly ash mix).

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The term Geopark is an interrelated phenomenon of geology, landscape, civilisation and society. One of the first Geopark areas in Turkey will be founded in the Kula district of Manisa. This region is an impressive area with its archaeological, historical and tourism-related features and its geological characteristics, such as cinders and maars, tectonic structures and earth pillars. Moreover, the earth pillars in the region present high-rockfall potential due to their geometric and lithologic peculiarities, formed by erosional processes. The present study aims in investigating the rockfall potential in this area by means of experimental investigation and numerical analyses. Extensive field studies including determination of earth pillar locations with rockfall potential, geological description of the earth pillars, scan-line surveys on discontinuities, identification of slope profiles, measurement of actual fallen block dimensions and sampling procedures were carried out. The eight earth pillar profiles were analysed to determine the run-out distances of basalt blocks and seven blocks were found to be capable of reaching the transportation line. For future protection purposes, barrier designs were suggested by computer analyses. Additional analyses were performed to determine rockfall-prone areas, taking into consideration the mapped rockfall source areas. Based on these analyses, the transportation line is threatened by potential rockfall. These results are in accordance with conclusions of the runout distance analyses. As a consequence, environmental aspects and rockfall phenomenon of the Kula Geopark Region must be taken into consideration during the planning process. It should also be pointed out that we have to own the values of geological heritages and to protect them based on the scientific and rational approaches.

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