Browsing by Author "Varol, O.O."

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Determination of Rock Mass Shear Strength Through Back Analysis Method: a Case Study
(Chamber of Mining Engineers of Turkey, 2021) Varol, O.O.; Ayhan, M.; Akın, M.
In this study, the slope failures were investigated in Avnik (Bingöl) iron open – pit mine. The slope instabilities occurred in highly weathered phyllite and schist units. The back analyses were carried out considering the limit equilibrium method and the shear strength parameters. While determining shear strength parameters via limit equilibrium method Hoek – Brown failure criterion was used. The GSI values (35 – 32) obtained by back analyses and GSI values (41 – 35) determined by field survey are compatible with each other. Hoek – Brown parameters for phyllite and schist units, which were obtained by back analyses are mb: 0.147 and 0.173, s: 3.305x10-5 and 8.,566x10-5, a: 0.516 and 0.511 respectively. © 2021 Union of Chambers of Engineers and Architects of Turkey. All rights reserved.
Evaluation of Rockfalls With 3-Dimensional Probabilistic Analyses and Empirical Methods: the Case of the Kayseri – Soğanlı Settlement
(TMMOB Chamber of Geological Engineers, 2023) Varol, O.O.; Akin, M.; Orhan, A.; Dinçer, İ.
This study evaluated the potential rockfall hazards in the Kayseri-Soğanlı settlement using the energy angle method and 3-dimensional probabilistic rockfall modeling. The high-resolution digital surface model (DSM) was obtained with the help of unmanned aerial vehicles (UAV) and high-resolution orthophoto. 3-dimensional probabilistic rockfall simulations were conducted on the DSM using the CONEFALL software, and rockfall zones were determined according to the energy line angle method. The dimensions of previously fallen rock blocks were determined using fieldwork and orthophoto generated by UAV. As a result of 3-dimensional probabilistic analyses, the maximum kinetic energy values of 15,000 kJ and bounce height of 15 m were determined during the movement of 3-meter rock blocks along the slope. When the energy line angle method was considered, it was found that the previously fallen blocks were mostly concentrated in the 40° energy line angle zone in the southern part of the slope. On the other hand, although the rolling lines obtained from probabilistic 3-dimensional rockfall analyses for 3 metre block size reach up to the maximum 30° energy line angle zone, these rolling lines end in the 40° energy line angle zone, especially in the southern part of the slope. Therefore, the empirical method, 3-dimensional probabilistic method, and the positions of measured blocks in the field show general consistency. © 2023, TMMOB Chamber of Geological Engineers. All rights reserved.
A General Overview of Pumice Mining in Van and Bitlis Provinces
(Union of Chambers of Engineers and Architects of Turkey, 2016) Varol, O.O.
In this literature study, the general characteristics of pumice stone are presented and the fact that more than 50% of total pumice reserve in our country exists in Bitlis and Van provinces is emphasized. Pumice with a hardness of 5-6 in accordance with the Mohs hardness scale and a specific gravity of 1-2 gr/cm3 has a variety of application areas ranging from construction and agriculture sectors to chemical industry. Mining with simple methods is an additional advantage of pumice. The maximum mining yield cannot be achieved and the pumice reserves are severely destroyed due to improper mining operations across both provinces with very high reserves. In case sufficient attention is paid to pumice mining in Van and Bitlis provinces.
Investigation of Slope Stability of Avnik (Bingöl) Open Pit Iron Mine by Different Methods
(Hacettepe Universitesi Yerbilmleri, 2023) Varol, O.O.; Ayhan, M.; Akin, M.
Avnik iron mine is the most important iron mine in our country, that is located in southeast of Bingöl province. In this study the slope stability of the Avnik iron mine that has a depth of 333 m was examined. In the field works, discontinuity survey was done and discontinuties properties were determined. As a result of the field studies, it was revealed that the metamorphic rocks in the study area have a highly fractured and fissured structure. On the other hand, instabilities with combined failure surfaces developed at two different the open pit mine previously. Corss - sections were taken along the open pit slopes which have critical stability condition and slope stability analyzes were performed on these cross - sections using limit equilibrium and finite element methods for static - dry and dynamic - dry conditions. According to the results of both methods, it wasdetermined that the factor of safety values for the slopes in the north of the open pit decreased in dynamic conditions and approached the critical limit equilibrium state. © 2023, Hacettepe Universitesi Yerbilmleri. All rights reserved.
Thermal Shock and Freeze-Thaw Resistance of Different Types of Carbonate Rocks
(Elsevier Ltd, 2021) Guler, S.; Türkmenoğlu, Z.F.; Varol, O.O.
In this study, the physical, mechanical and index properties of 6 different carbonate rocks, taken from quarries in the East Anatolian region of Turkey and commonly used for decorative purposes in buildings, were investigated after the thermal shock (T-S) and freeze thaw (F-T) effects. Compared to room temperature conditions, attempts were made to determine the variation in physical and mechanical properties like porosity, mass loss, roughness, gloss, Schmidt hardness (SH), P-wave velocities (Vp) and uniaxial compressive strength (UCS) occurring in carbonate rocks as a result of T-S and F-T cycles. Additionally, SEM analysis was performed on 2 rocks with worst and best physical and mechanical properties at room temperature and the causes of variations in the microstructure of these carbonate rocks were discussed. According to the obtained results, as the number of T-S and F-T cycles increase, the degradation of the internal structure of the carbonate rocks increases and as a result, resistance to physical and mechanical effects significantly reduces. Additionally, the F-T effect was determined to negatively affect the internal structure of the carbonate rocks in greater amounts compared to the T-S effect. It was determined that UCS of the carbonate rocks decreased between 16.14-28.65% and 22.96–45.66% after 50 T-S and F-T cycles, respectively. As the L4 rock sample (Tamara Bej) has fewer flaws in the internal structure compared to other rocks, it was identified to be more favorable for decorative use in buildings. © 2020 Elsevier Ltd