A new approach to rock brittleness and its usability at prediction of drillability

Özfirat M.K. | Yenice H. | Şimşir F. | Yarali O.

Article | 2016 | Journal of African Earth Sciences119 , pp.94 - 101

Rock brittleness is one of the most important issues in rock drilling and cutting. The relations between drillability and brittleness will assist engineers in excavation works. The demand for representative rock parameters related to planning of underground excavations is increasing, as these parameters constitute fundamental input for obtaining the most reliable cost and time estimates. In rock cutting mechanics, the effects of the rock and brittleness on the efficiency of drilling and excavation are examined by many researchers. In this study, 41 different rock types were tested in laboratory to investigate the relations between t . . .he drilling rate index and different brittleness values. Firstly, the relations defined in literature are tested. Strength tests are made according to International Society for Rock Mechanics standards. In addition Norwegian University of Science and Technology standards are used to determine drilling rate index. Then, a new brittleness index is proposed which is the arithmetic average of uniaxial compressive strength and tensile strength. Considering the regression analysis carried out, it was seen that the proposed formula showed good correlation for these samples handled in this study. As a result of this study, a high correlation is obtained between the proposed index and drilling rate index values (R:0.84). The results are found to be at least reliable as well as other brittleness equations given in literature. © 2016 Elsevier Ltd Daha fazlası Daha az

The 3-D strain patterns in Turkey using geodetic velocity fields from the RTK-CORS (TR) network

Kutoglu H.S. | Toker M. | Mekik C.

Article | 2016 | Journal of African Earth Sciences115 , pp.246 - 270

This study presents our use of GPS data to obtain and quantify the full continuous strain tensor using a 3-D velocity field in Turkey. In this study, GPS velocities improve the estimation of short-term strain tensor fields for determining the seismic hazard of Turkey. The tensorial analysis presents different aspects of deformation, such as the normal and shear strains, including their directions, the compressional and extensional strains. This analysis is appropriate for the characterizing the state of the current seismic deformation. GPS velocity data from continuous measurements (2009-2012) to estimate deformations were processed . . . using the GAMIT/GLOBK software. Using high-rate GPS data from permanent 146 GNSS stations (RTK-CORS-TR network), the strain distribution was determined and interpolated using a biharmonic spline technique. We show the strain field patterns within axial and plane form at several critical locations, and discuss these results within the context of the seismic and tectonic deformation of Turkey. We conclude that the knowledge of the crustal strain patterns provides important information on the location of the main faults and strain accumulation for the hazard assessment. The results show an agreement between the seismic and tectonic strains confirming that there are active crustal deformations in Turkey. © 2015 Elsevier Ltd Daha fazlası Daha az

Erratum: Corrigendum to “The 3-D strain patterns in Turkey using geodetic velocity fields from the RTK-CORS (TR) network” (Journal of African Earth Sciences (2016) 115 (246–270)(S1464343X15301242)(10.1016/j.jafrearsci.2015.12.002))

Kutoglu H.S. | Toker M. | Mekik C.

Erratum | 2016 | Journal of African Earth Sciences124 , pp.517 - 518

In the article titled “The 3-D Strain patterns in Turkey using Geodetic velocity fields from the RTK-CORS (TR) Network” published in Journal of African Earth Sciences Vol. 11, pp.246–270, the black arrows on the Figs. 10 and 12 are shifted due to printing error to undesired places. The correct form of Figs. 10 and 12 are given below: Fig. 10. Normal strain in the y-axis (max rms = ± 2 × 10-5 ppb). The westerly black arrow refers to the Tekirdag basin and the easterly arrow refers to the Çınarcik basin. Note the compressional strain in the ruptured zone of the 2011 Van earthquake (LV) consistent with its aftershock distribution (6000 . . . events) (see Fig. 2). Fig. 12. Shear strain in the xy-plane (max rms = ± 7.7 × 10-6 ppb). Note the anomalous circular closure of extensional shear strains in the center of EAAP, LV and the compressional shear strains in the W-part of MS and KTJ (see Fig. 2). © 201 Daha fazlası Daha az

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