Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12573/395
Browse
2 results
Search Results
Article Citation - WoS: 5Citation - Scopus: 5Investigations on Fracture Evolution of Coal Measure Sandstones from Mineralogical and Textural Points of View(Springer India, 2020-04-09) Koken, EkinThe purpose of the present study is to investigate the variations in fracture evolution of sandstones arising from mineralogical and textural features. For this purpose, eight types of coal measure sandstones located in the Zonguldak Hardcoal Basin (ZHB) were considered. The mineralogical and textural characterizations of the rocks were carried out. Physico-mechanical properties were determined for each rock type. Based on quantitative strain-based methods, the crack initiation (sigma(ci)) and crack damage (sigma(cd)) thresholds of the sandstones were determined. The laboratory test results indicate that the sigma(ci)and sigma(cd)of the sandstones were found to be between 0.27-0.43 and 0.61-0.83 of the UCS, respectively. In general, the sigma(ci)and sigma(cd)correspond to 0.37 and 0.71 of the UCS, respectively. The sigma(ci)and sigma(cd)decrease with increasing the sorting coefficient (S-c), average grain size (d(50), mm), contents of feldspar (F, %), and lithic fragment (LF, %). On the other hand, increasing quartz content (Qtz, %) increases those variables. Remarkable changes were obtained in the sigma(ci)and sigma(cd)when effective porosity (n(e)) and pulse wave velocity (V-p) of the rocks exceed 3% and 3.00 km/s, respectively. As a result of mineralogical analyses and laboratory studies, statistical analyses were carried out. Accordingly, the sigma(ci)and sigma(cd)could be estimated reliably using several empirical relationships established in the present study. In order to represent the importance and utilization of rock mineralogy and texture for underground mining applications in the ZHB, several suggestions and considerations related to aV-cut gallery blasting operation were introduced.Article Citation - WoS: 10Citation - Scopus: 9Assessment of Deformation Properties of CoAl Measure Sandstones Through Regression Analyses and Artificial Neural Networks(Polska Akad Nauk, Polish Acad Sciences, 2023-07-24) Koken, EkinThe deformation properties of rocks play a crucial role in handling most geomechanical problems. However, the determination of these properties in laboratory is costly and necessitates special equipment. Therefore, many attempts were made to estimate these properties using different techniques. In this study, various statistical and soft computing methods were employed to predict the tangential Young Modulus (Eti, GPa) and tangential Poisson's Ratio (vti) of coal measure sandstones located in Zonguldak Hardcoal Basin (ZHB), NW Turkey. Predictive models were established based on various regression and artificial neural network (ANN) analyses, including physicomechanical, mineralogical, and textural properties of rocks. The analysis results showed that the mineralogical features such as the contents of quartz (Q, %) and lithic fragment (LF, %) and the textural features (i.e., average grain size, d50, and sorting coefficient, Sc) have remarkable impacts on deformation properties of the investigated sandstones. By comparison with these features, the mineralogical effects seem to be more effective in predicting the Eti and vti. The performance of the established models was assessed using several statistical indicators. The predicted results from the proposed models were compared to one another. It was concluded that the empirical models based on the ANN were found to be the most convenient tools for evaluating the deformational properties of the investigated sandstones.