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    3D Modeling of Ripping Process
    (Asce-Amer Soc Civil Engineers, 2008) Basarir, Hakan; Karpuz, Celal; Tutluoglu, Levent
    Due to environmental constraints and limitations on blasting, ripping as a ground loosening and breaking method has become more popular than drilling and blasting method in both mining and civil engineering applications. The best way of estimating the rippability of rocks is to conduct direct ripping runs in the field. However, it is not possible to conduct direct ripping runs in all sites using different dozer types. Therefore, the utilization of numerical modeling of ripping systems becomes unavoidable. A complex ripping system can better be understood with three-dimensional (3D) models rather than two-dimensional models. In this study, 3D distinct element program called 3DEC was used to investigate the ripping process. First, the ripping mechanisms were investigated and then the individual factors that affect the rippability performance of dozers were reviewed. The rippabilities of rocks depend not only on the rock properties, but also machine or dozer properties. Thus, ripper production and rock rippability with D8 type of dozers were also determined by direct ripping runs on different open pit lignite mines within the scope of this research. Production values obtained from numerical modeling were compared with field production values obtained from the case studies. This comparison shows that the model gives consistent and adequate results. Hence, a link has been established between the field results and the 3D models.
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    Analysis of rock-support interaction using numerical and multiple regression modeling
    (Canadian Science Publishing, 2008) Basarir, Hakan
    This paper presents the results of performance analysis on the support systems recommended by the RMR (rock mass rating) rock mass classification system. Rock-support interaction is analyzed by means of both numerical and multiple regression modeling. Five different rock mass conditions were assumed from very poor to very good, each representing varied RMR. Extensive computer simulations were conducted to investigate the stresses, displacements, and yielded zones around a circular opening excavated at different depths, and under different rock conditions. The performances of the RMR recommended support systems were analyzed and the stability of excavation was evaluated. Multiple regression modeling was conducted to assess the relationship between support pressure, depth, and tunnel deformation for different rock conditions. Regression models were derived and the response surfaces were constructed, showing the interaction between tunnel depth, support pressure, and tunnel displacement. Using the derived models and the constructed response surfaces, engineers are able to describe the support performance and assess the practical range of expected deformation for their specific site conditions. Also, the approach presented can be used for any special case.
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    Assessment of slope stability using fuzzy sets and systems
    (Taylor & Francis Ltd, 2013) Basarir, Hakan; Saiang, David
    To assess the stability of slopes, mining and geotechnical engineers frequently use empirical rock mass classification and characterisation systems. These methods are practical and often very useful in the preliminary design stage. Slope mass rating (SMR) system is one of the commonly used empirical methods to assess the stability of slopes. The SMR is obtained correcting basic rock mass rating (RMR) using four joint adjustment factors that consider the geomechanical relationship between the slope face and the joint affecting rock mass as well as the excavation method used. The factors included in the SMR system such as basic RMR, and correction factors involve some drawbacks such as uncertainties sourced from qualitative criteria, sharp class boundaries and fixed rating scales. These drawbacks are sourced from the complex nature of rock mass. To deal with these uncertainties, the fuzzy set theory is applied in this study to reliably determine basic RMR and adjustment factors. It was seen that fuzzy set theory can sufficiently cope with the common drawbacks in the determination of factors included in the SMR system.
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    Engineering geological evaluation and preliminary support design for the metro extension tunnel, Ankara, Turkey
    (Springer Heidelberg, 2009) Ozsan, Aydm; Basarir, Hakan; Yuceel, Serdar; Cucen, Ozkan
    The paper reports an assessment of the engineering geological characteristics of the rock mass to be encountered between Mecidiye and Gazino stations on the new extension of the Ankara metro and the determination of appropriate support and excavation methods. The rock mass quality was estimated using the rock mass rating (RMR), geological strength index (GSI) and rock mass quality (Q) systems and the tunnel divided into sections. The RMR, Q and NATM systems were used to determine the support and excavation methods in these areas. The deformations and stress concentrations around each tunnel section were investigated and the interaction of the support systems with the rock mass was analyzed using finite element software. It is concluded that rock mass classification systems should be used in tandem with numerical tools, although it is emphasized that the estimation of rock mass properties is not an exact science and both rock properties and numerical models should be refined based on observations and the results of instrumentation installed during the construction of a tunnel.
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    Geostatistical modeling of spatial variability of SPT data for a borax stockpile site
    (Elsevier Science Bv, 2010) Basarir, Hakan; Kumral, Mustafa; Karpuz, Celal; Tutluoglu, Levent
    The major borax producer, Eti Mining Co. of Turkey, planned to construct an export stock site located near the Bandirma Harbor in the northwestern of Turkey. During this construction, some stability problems were encountered. To analyze the stability problems and to assess the engineering properties of soil in the stock site geotechnical investigations were started. As a part of geotechnical investigations one of the most common field tests, the standard penetration tests (SPT), was conducted for soil exploration. In this study, the field is geostatistically simulated to assess the uncertainty associated with the spatial variability of SPT results. Multiple probable realizations of SPT values are generated using sequential Gaussian simulation. Using 122 NSPT data in the borax stockpile site, the characteristics observed in the available data are reproduced in a manner that the heterogeneity of SPT within the field is honored. The estimated NSPT data can also be used for other purposes such as determination of bearing capacity, and estimation of soil strength parameters. (C) 2010 Elsevier B.V. All rights reserved.