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Öğe Analyses of acoustic emission response of a fault breccia in uniaxial deformation(SPRINGER HEIDELBERG, 2010) Slatalla, N.; Alber, M.; Kahraman, S.Interpretation of mechanical tests on block-in-matrix rocks (bimrocks) is difficult and often open to dispute as, with deformation, the interactions between blocks, matrix and pores are complex, reflecting the influence of their different shape, size, strength and stiffness. The acoustic emission (AE) technique can be used to record an ultrasound pulse emitted by a defect within the sample at the moment of its occurrence. Typically several deformations occur, such as crack closure, crack initiation or permanent crack damage, but they may be difficult to visualize with a fault breccia. Consequently, with fault breccia it is advisable to focus on the primary stage of deformation where the acoustic emission response may be traced to properties of the breccia, such as block proportions. The paper shows that the different geometrical properties, particularly the volumetric block proportions, are reflected by stress concentrations which in turn trigger specific AE signatures.Öğe Estimating unconfined compressive strength and elastic modulus of a fault breccia mixture of weak blocks and strong matrix(PERGAMON-ELSEVIER SCIENCE LTD, 2006) Kahraman, S.; Alber, M.[Abstract Not Available]Öğe Evaluating the geomechanical properties of Misis fault breccia (Turkey)(PERGAMON-ELSEVIER SCIENCE LTD, 2008) Kahraman, S.; Alber, M.; Fener, M.; Gunaydin, O.This study investigated the correlations between the uniaxial compressive strength (UCS), elastic modulus (E) or the differential stress (Delta sigma) and density, P- and S-wave velocity, volumetric block proportion (VBP), average block diameter (($) over bar (block)), average block diameter factor (ABD(F)), aspect ratio and roundness. The results were evaluated by both simple and multiple regression analysis. Simple regression analysis results show no correlation between UCS, E or Delta sigma and the other examined parameters, except S-wave velocity. A correlation was, however, found between UCS and S-wave velocity for 25% and 75% VBP. Other significant models including density, P- and S-wave velocity and textural properties for the prediction of UCS and Ds were found by multiple regression analysis. From these results it is concluded that the strength of the Misis fault breccia cannot be defined by a single parameter such as VBP as is the case for some bimrocks. It is also concluded that the models developed by multiple regression analysis can be used to predict the UCS and Ds of the Misis fault breccia. The multiple regression models including two or three independent variables are the most practical equations. Using these equations to predict the UCS and Ds of the fault breccia is easier, faster and cheaper than conducting triaxial or uniaxial compressive strength tests. (C) 2008 Elsevier Ltd. All rights reserved.Öğe Evaluating the strength and deformability properties of Misis fault breccia using artificial neural networks(PERGAMON-ELSEVIER SCIENCE LTD, 2009) Kahraman, S.; Gunaydin, O.; Alber, M.; Fener, M.Since the preparation of smooth specimens from the fault breccias are usually difficult and expensive, the development of some predictive models for the geomechanical properties of fault breccias will be useful. In this study, artificial neural networks (ANNs) analysis was applied on the data pertaining to Misis fault breccia to develop some predictive models for the uniaxial compressive strength (UCS) and elastic modulus (E) from the indirect methods. The developed ANNs models were also compared with the regression models. As a result of ANNs analysis, very good models were derived for both UCS and E estimation. It was shown that ANNs models were more reliable than the regression models. Concluding remark is that UCS and E values of Misis fault breccia can reliably be estimated from the indirect methods using ANNs analysis. (c) 2008 Elsevier Ltd. All rights reserved.Öğe Predicting the uniaxial compressive strength and elastic modulus of a fault breccia from texture coefficient(SPRINGER WIEN, 2009) Alber, M.; Kahraman, S.[Abstract Not Available]Öğe The usability of Cerchar abrasivity index for the prediction of UCS and E of Misis Fault Breccia: Regression and artificial neural networks analysis(PERGAMON-ELSEVIER SCIENCE LTD, 2010) Kahraman, S.; Alber, M.; Fener, M.; Gunaydin, O.The derivation of some predictive models for the geomechanical properties of fault breccias will be useful due to the fact that the preparation of smooth specimens from the fault breccias is usually difficult and expensive. To develop some predictive models for the uniaxial compressive strength (UCS) and elastic modulus (E) from the indirect methods including the Cerchar abrasivity index (CAI), regression and artificial neural networks (ANNs) analysis were applied on the data pertaining to Misis Fault Breccia. The CAI was included to the best regression model for the prediction of UCS. However, the CAI was not included to the best regression model for the prediction of E. The developed ANNs model was also compared with the regression model. It was concluded that the CAI is a useful property for the prediction of UCS of Misis Fault Breccia. Another conclusion is that ANNs model is more reliable than the regression models. (C) 2010 Elsevier Ltd. All rights reserved.Öğe Triaxial strength of a fault breccia of weak rocks in a strong matrix(SPRINGER HEIDELBERG, 2008) Kahraman, S.; Alber, M.Triaxial strengths are difficult to obtain when the rock is very heterogeneous with respect to particle size and particle lithology and the samples are difficult to obtain and prepare. A fault breccia with clasts weaker than the matrix was investigated. It was found that its strength was related to the proportion of the blocks and the size of the specimen. The volumetric block proportion and texture coefficient were evaluated by core scanning and image processing. Triaxial compressive strength tests were conducted on different sized cores and different proportions of blocks. The most accurate estimations of the lower bound strength were obtained using larger diameter cores and samples with a higher volumetric block proportion.
